0001619856-24-000013 | 10-K | XBRL Viewer

Print Document View Excel Document

Summary of Significant Accounting Policies - Schedule of Concentration of Credit Risk and other Uncertainties (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenue \| Licensee A
Concentration Risk [Line Items]
Total		16.20%
Revenue \| Licensee B
Concentration Risk [Line Items]
Total	71.90%	57.40%
Revenue \| Total
Concentration Risk [Line Items]
Total	71.90%	73.60%
Accounts Receivable and Contract Assets \| Licensee A
Concentration Risk [Line Items]
Total	47.50%	23.80%
Accounts Receivable and Contract Assets \| Licensee B
Concentration Risk [Line Items]
Total		36.60%
Accounts Receivable and Contract Assets \| Total
Concentration Risk [Line Items]
Total	47.50%	60.40%

Income Taxes - Schedule of Reconciliation of Statutory Income Tax Rate to Our Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Federal income tax (benefit) at statutory rate	(21.00%)	(21.00%)
State taxes, net of federal benefit	(6.00%)	(8.00%)
Stock-based compensation	1.00%	0.00%
R&D tax credits, net of reserves	(4.00%)	(3.00%)
Other	0.00%	1.00%
Effective income tax rate	0.00%	0.00%
Federal
Income Tax Contingency [Line Items]
Change in valuation allowance	24.00%	23.00%
State
Income Tax Contingency [Line Items]
Change in valuation allowance	6.00%	8.00%

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Licensing and collaboration revenue (including $2,393 and $0, from related parties)	$ 34,477	$ 13,851
Operating expenses:
Research and development	112,075	82,230
General and administrative	38,461	38,020
Total operating expenses	150,536	120,250
Loss from operations	(116,059)	(106,399)
Other income (expense):
Change in fair value of equity securities	(6)	(133)
Change in fair value of the MSKCC success payments liability	(1,288)	2,429
Other income, net	15,476	4,752
Total other income	14,182	7,048
Net loss before provision for income taxes	(101,877)	(99,351)
Provision for income taxes	193	70
Net loss	(102,070)	(99,421)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale marketable securities	1,548	(1,383)
Net comprehensive loss	$ (100,522)	$ (100,804)
Net loss per share, basic (in dollars per share)	$ (1.38)	$ (1.64)
Net loss per share, diluted (in dollars per share)	$ (1.38)	$ (1.64)
Weighted average common shares outstanding, basic (in shares)	73,807,597	60,801,133
Weighted average common shares outstanding, diluted (in shares)	73,807,597	60,801,133

Balance Sheet Items

12 Months Ended

Dec. 31, 2023

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Items

Other receivables consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Patent cost reimbursements	$	1,403	$	1,638
Accrued interest on marketable securities	702		570
Other	181		7
Total	$	2,286	$	2,215

Prepaid expenses and other current assets consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Prepaid contract manufacturing and clinical costs	$	3,942	$	4,803
Prepaid income taxes	—		431
Prepaid insurance	993		1,568
Other	1,220		1,119
Total	$	6,155	$	7,921

Property and equipment, net, consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Lab equipment	$	15,581	$	12,588
Leasehold improvements	2,235		1,876
Computer equipment	895		709
Furniture and office equipment	499		161
Construction in progress	8,204		993
Total property and equipment	27,414		16,327
Less accumulated depreciation and amortization	(9,144)		(5,649)
Property and equipment, net	$	18,270	$	10,678

Depreciation and amortization expenses related to property and equipment were $3.5 million and $1.6 million, for the years ended December 31, 2023, and 2022, respectively.

Accrued expenses and other current liabilities consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Accrued employee compensation and related expenses	9,517		5,752
Accrued research and development expenses	8,720		6,731
Accrued patent expenses	613		1,331
Accrued expenses related to sublicensing revenues	802		596
Credit card liability	377		299
Other	1,106		1,370
Total	$	21,135	$	16,079

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Summary of Components of Lease Costs

The components of lease costs, which are included in our statements of operations and comprehensive loss, were as follows (in thousands):


	Years Ended December 31,
	2023		2022
Operating lease cost(1)	$	7,628	$	7,337
Short-term lease cost	250		83
Total lease cost	$	7,878	$	7,420

(1)Includes $2.5 million and $2.2 million of variable lease cost related to operating expenses and taxes for the years ended December 31, 2023, and 2022, respectively.

Schedule of Supplemental Information Related to Leases

Supplemental information related to our leases was as follows (in thousands):


	Years Ended December 31,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	3,732	$	3,468

The following table summarizes the weighted-average remaining lease term and weighted-average discount rate for our corporate laboratory and office leases:


	Years Ended December 31,
	2023		2022
Weighted-average remaining lease term (years)	7.4		8.3
Weighted-average discount rate	11.3	%	11.3	%

Summary of Future Minimum Lease Payment Under Leases

The following table summarizes a maturity analysis of our operating lease liabilities showing the aggregate lease payments as of December 31, 2023:


Year ending December 31:	(in thousands)
2024(1)	$	3,485
2025	4,475
2026	5,720
2027	5,922
2028	6,122
Thereafter	15,993
Total future undiscounted lease payments	41,717
Less imputed interest	(14,609)
Total discounted lease payments	27,108
Less current portion of lease liability	(1,200)
Noncurrent portion of lease liability	$	25,908

(1)Reflects an offset of $1.0 million related to incentives expected to be received in 2024.

Leases - Supplemental Information Related To Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating cash flows from operating leases	$ 3,732	$ 3,468
Weighted-average remaining lease term (years)	7 years 4 months 24 days	8 years 3 months 18 days
Weighted-average discount rate	11.30%	11.30%

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Assumptions Used in Valuation of MSKCC Success Payments Liability (Details)	12 Months Ended
	Dec. 31, 2023 $ / shares	Dec. 31, 2022 $ / shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair market value common stock per share value threshold	$ 5.1914
Fair value of common stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, measurement input	5.73	6.28
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, measurement input	0.000388	0.000388
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, measurement input	0.0079	0.0079
Probability of achieving multiple of initial share price \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, measurement input	0.052	0.030
Probability of achieving multiple of initial share price \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability, measurement input	0.181	0.106
Expected term (years) \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (years)	3 years 8 months 12 days	4 years 7 months 6 days
Expected term (years) \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected term (years)	5 years 2 months 12 days	6 years

Balance Sheet Items - Schedule of Other Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Patent cost reimbursements	$ 1,403	$ 1,638
Accrued interest on marketable securities	702	570
Other	181	7
Total	$ 2,286	$ 2,215

Related Party Transactions - Additional Information (Details) - USD ($)				12 Months Ended
	Jun. 30, 2023	Jun. 29, 2023	May 15, 2020	Dec. 31, 2023	Dec. 31, 2022	May 16, 2023	Nov. 13, 2020
Related Party Transaction [Line Items]
Carrying value of investment				$ 7,753,000	$ 7,698,000
Revenue				$ 34,477,000	$ 13,851,000
Common stock, par value (in dollars per share)	$ 0.0001			$ 0.0001	$ 0.0001		$ 5.1914
Term of agreement		36 months
Period of right of first negotiation		30 days
Proceeds from issuance of common stock in a private placement with Pfizer				$ 17,290,000	$ 0
Contract with customer liability increase for new contract		$ 7,500,000
Contract with customer, liability				8,949,000	25,891,000
Deferred revenue, current				2,847,000	9,937,000
Deferred revenue, net of current portion				6,102,000	15,954,000
Pfizer
Related Party Transaction [Line Items]
Term of agreement		36 months
Investment owned, percentage		4.99%
Proceeds from issuance of common stock in a private placement with Pfizer		$ 17,500,000
Pfizer \| Related Party
Related Party Transaction [Line Items]
Revenue				1,200,000
Contract with customer, liability				6,200,000
Deferred revenue, current				2,500,000
Deferred revenue, net of current portion				3,700,000
Edge Animal Health
Related Party Transaction [Line Items]
Related party, option term						3 years
Revenue				1,200,000	0
Private Placement
Related Party Transaction [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	4,690,431
Public offering price (in dollars per share)	$ 5.33
Consideration received on transaction	$ 25,000,000
Private Company License Agreement \| Convertible Preferred Stock
Related Party Transaction [Line Items]
Convertible preferred stock, issued during period, acquisition (in shares)			7,500,000
Fair value of convertible preferred stock			$ 7,500,000
Carrying value of investment				$ 7,500,000	$ 7,500,000

Income Taxes - Schedule of Benefit from Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current income taxes
Federal	$ 0	$ 163
State	15	2
Total current income tax expense	15	165
Deferred income taxes:
Federal	1	0
State	177	(95)
Total deferred income tax (benefit) expense	178	(95)
Total income tax expense	$ 193	$ 70

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Description of the Business, Organization, and Liquidity (Details) $ / shares in Units, $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
	Feb. 29, 2024 USD ($) $ / shares shares	Aug. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) subsidiary $ / shares shares	Dec. 31, 2022 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of subsidiaries \| subsidiary			4
Accumulated deficit			$ (299,285)	$ (197,215)
Net loss			(102,070)	(99,421)
Cash generated in operating activities			(93,291)	$ (90,966)
Cash, cash equivalents and short term marketable securities			$ 372,400
Public Stock Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares		22,115,384
Consideration received on transaction		$ 134,400
Public offering price (in dollars per share) \| $ / shares		$ 6.50
Sale of stock aggregate gross proceeds		$ 143,700
Over-Allotment Option
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares		2,884,615
At The Market ATM Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares			168,635
Consideration received on transaction			$ 1,000
Public offering price (in dollars per share) \| $ / shares			$ 7.32
Sale of stock aggregate gross proceeds			$ 1,200
At The Market ATM Offering \| Subsequent Event
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares	1,594,171
Consideration received on transaction	$ 11,300
Public offering price (in dollars per share) \| $ / shares	$ 7.33
Sale of stock aggregate gross proceeds	$ 11,700

Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance (in shares)	17,084,128	13,867,717
Stock options, issued and outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance (in shares)	9,410,404	6,733,074
Stock options, authorized for future issuance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance (in shares)	5,952,012	5,833,979
Stock available under our employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance (in shares)	1,516,355	1,044,518
Unvested restricted stock units and performance-based restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance (in shares)	205,357	256,146

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(02)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Leases - Summary of Components of Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease cost	$ 7,628	$ 7,337
Short-term lease cost	250	83
Total lease cost	7,878	7,420
Variable lease cost	$ 2,500	$ 2,200

Balance Sheet Items - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization expense related to property and equipment	$ 3.5	$ 1.6

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Edge Animal Health On May 15, 2020, we entered into an Exclusive License Agreement for Veterinary Therapeutics (as amended, “Edge chRDNA License Agreement”) with Edge Animal Health (“Edge”), a private company, related party, under which we granted Edge an exclusive worldwide license to Cas9 and Cas12a chRDNA intellectual property rights and know-how in the defined field of veterinary therapeutics. As consideration for this exclusive license, Edge issued to us 7,500,000 shares of convertible preferred stock with an estimated fair value of $7.5 million, which was the price paid for similar shares by another investor, and which was an arm’s length transaction. This represents a material voting interest in Edge and entitles us to hold one of the four board of director seats. As of December 31, 2023, we had appointed one of the four Edge directors. We concluded that Edge is a variable interest entity and that we are not its primary beneficiary based on our representation on its board of directors. As Edge’s convertible preferred stock is not in substance common stock, we recorded this investment using the measurement alternative. As of each of December 31, 2023 and 2022, the carrying value of the Edge investment was $7.5 million. There have been no changes to the carrying value of the investment during the years ended December 31, 2023 and 2022. On May 16, 2023, we entered into an Exclusive License Agreement for Veterinary Therapeutics (CRISPR-Cas9) (“Edge Cas9 License Agreement”), under which we granted Edge an exclusive worldwide license to certain CRISPR-Cas9 intellectual property rights in the field of veterinary therapeutics. Previously, on May 15, 2020, we had entered into an Option for an Exclusive License under which Edge could exercise its option within three years upon payment of a total of $1.2 million, which Edge paid, and we entered into the Edge Cas9 License Agreement. We recognized $1.2 million of revenue in connection with the Edge Cas9 License Agreement during the twelve months ended December 31, 2023. We did not recognize any revenue in connection with the Edge Cas9 License Agreement in 2022. Pfizer Investment On June 29, 2023, we entered into a Securities Purchase Agreement (“Securities Purchase Agreement”) with Pfizer, pursuant to which we, in a private placement transaction, issued and sold to Pfizer 4,690,431 shares of our common stock, par value $0.0001 per share, at a purchase price of $5.33 per share, for aggregate gross proceeds of approximately $25.0 million (“Pfizer Investment”). The issuance and sale of the shares to Pfizer closed on June 30, 2023. We granted certain registration rights to Pfizer under the Securities Purchase Agreement covering the resale of the shares. Unless otherwise agreed by Pfizer, we agreed to use the proceeds from the Pfizer Investment solely in connection with (i) the development program for our allogeneic anti-BCMA CAR-T cell therapy known as CB-011 that is being evaluated in our CaMMouflage clinical trial and/or (ii) any other single-targeted anti-BCMA CAR-T cell therapy using an anti-BCMA single-chain variable fragment owned or controlled by us (collectively, cell therapies described in clauses (i) and (ii) are referred to as a “BCMA Product Candidate”), for 36 months beginning on June 29, 2023. On June 29, 2023, in connection with the Pfizer Investment, we and Pfizer also entered into an Information Rights Agreement, having a thirty-six (36)-month term. Under the Information Rights Agreement, we granted Pfizer a thirty (30)-calendar day right of first negotiation (“ROFN”) if we commence or engage with any third party with respect to a potential grant of rights to develop and/or commercialize a BCMA Product Candidate, including, without limitation, a license agreement, a co-promotion/co-commercialization agreement, a profit share agreement, a joint venture agreement, or an asset sale agreement (a “Grant of Program Rights”). If we and Pfizer do not reach an agreement with respect to a Grant of Program Rights within the 30-day period, then we may pursue negotiations and enter into an agreement with any third party. If we and such third party do not reach agreement on the Grant of Program Rights within a specified time period, Pfizer’s right of first negotiation will be reinstated. Under the Information Rights Agreement, we also agreed to grant Pfizer the right to designate one representative to serve on our scientific advisory board (“SAB”). Through an information sharing committee, we provide calendar quarter updates to Pfizer regarding the development program for a BCMA Product Candidate. Additionally, we agreed to provide Pfizer access to any preclinical or interim or final clinical data (including raw data) and results generated as part of the development program for a BCMA Product Candidate at the same time that we provide such data to a third party (other than to our service providers or the FDA or other regulatory authorities), subject to certain confidentiality exceptions. On June 29, 2023, we and Pfizer also entered into a Voting Agreement, pursuant to which, for a period of 12 months, Pfizer agreed to cause our voting securities that Pfizer beneficially owns (within the meaning of Rules 13d-3 or 13d-5 under the Securities Exchange Act of 1934, as amended (“Exchange Act”)) in excess of 4.99% of our then issued and outstanding voting securities to be voted (i) with respect to any matter directly relating to remuneration of directors, directors’ insurance, or indemnification or release from liability of directors, in a manner proportionally consistent with the votes properly cast for and against by holders of voting securities not beneficially owned by Pfizer, and (ii) with respect to any other matter in which Pfizer shall have the right to vote such voting securities, in accordance with the recommendation of our board of directors or any applicable committee thereof. We recorded the issuance of our common stock at its estimated fair value of $17.5 million, which reflects a discount for the lack of marketability of the shares. The remaining $7.5 million of the aggregate purchase price was allocated to the Information Rights Agreement, which represented a contract with a customer under ASC 606. We concluded that the information sharing committee represents the only performance obligation under the Information Rights Agreement. The ROFN does not provide Pfizer with a material right and is therefore not a performance obligation. We recognize revenue over time as the measure of progress which we believe best depicts the obligations to Pfizer. The information sharing committee will meet quarterly over the 36-month term of the Information Rights Agreement, which results in recognition of the transaction price over the 36-month term. During the twelve months ended December 31, 2023, we recognized $1.2 million of revenue from Pfizer. As of December 31, 2023, there was approximately $6.2 million of related party deferred revenue ($2.5 million included in current liabilities and $3.7 million included in long-term liabilities) related to our performance obligation to Pfizer.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Change in Fair Value of Financial Liability (Details) - MSKCC success payments liability - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ 1,651	$ 4,080
Change in fair value	1,288	(2,429)
Ending balance	$ 2,939	$ 1,651

Net Loss Per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Net Loss Per Share

The following table sets forth the computation of the basic and diluted net loss per share (in thousands, except share and per share amounts):


	Years Ended December 31,
	2023		2022
Numerator:
Net loss	$	(102,070)	$	(99,421)
Denominator:
Weighted-average common shares outstanding used to compute net loss per share, basic and diluted	73,807,597		60,801,133
Net loss per share, basic and diluted	$	(1.38)	$	(1.64)

Because we were in a net loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods, as the inclusion of all common stock equivalents outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:


	As of December 31, 2023	As of December 31, 2022
Stock options outstanding	9,410,404	6,733,074
RSUs issued and outstanding	153,000	256,146
Shares available under ESPP	134,276	49,109
	9,697,680	7,038,329

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (102,070)	$ (99,421)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,525	1,622
Gain on disposal of fixed assets	(34)	0
Non-cash consideration for licensing and collaboration revenue	(61)	(205)
Change in fair value of equity securities	6	133
Stock-based compensation expense	13,750	11,716
Change in fair value of MSKCC success payments liability	1,288	(2,429)
Acquired in-process research and development	0	600
Accretion of discounts on investments in marketable securities, net	(4,425)	(797)
Non-cash lease expense	2,048	2,019
Changes in operating assets and liabilities:
Accounts receivable	54	951
Contract assets	822	(759)
Other receivables	(71)	3,268
Prepaid expenses and other current assets	1,766	(975)
Other assets	(48)	(564)
Accounts payable	1,819	(2,721)
Accrued expenses and other current liabilities	5,743	1,953
Deferred revenue, current and long-term	(16,943)	(4,844)
Operating lease liabilities	(637)	(403)
Other liabilities	0	(15)
Deferred tax liabilities	177	(95)
Net cash used in operating activities	(93,291)	(90,966)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales and maturities of marketable securities	338,188	252,868
Purchases of marketable securities	(394,758)	(339,063)
Purchases of property and equipment	(11,613)	(6,454)
Payments to acquire in-process research and development	0	(600)
Net cash used in investing activities	(68,183)	(93,249)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from public follow-on public offering, net of offering expenses	134,423	0
Proceeds from issuance of common stock in a private placement with Pfizer	17,290	0
Proceeds from exercise of stock options and purchases of common stock under employee stock purchase plan	1,578	2,133
Proceeds from issuance of common stock related to at-the-market offering, net of offering expenses	1,007	0
Net cash provided by financing activities	154,298	2,133
NET DECREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(7,176)	(182,082)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — BEGINNING OF PERIOD	58,384	240,466
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — END OF PERIOD	51,208	58,384
RECONCILIATION OF CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Cash and cash equivalents	51,162	58,338
Restricted cash	46	46
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH ON THE BALANCE SHEET	51,208	58,384
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for income taxes	170	0
SUPPLEMENTAL SCHEDULE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchases of property and equipment included in accounts payable and accrued expenses	692	1,223
Right-of-use-assets obtained in exchange for new operating lease liabilities	$ 0	$ 26,249

Balance Sheet Items - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepaid contract manufacturing and clinical costs	$ 3,942	$ 4,803
Prepaid income taxes	0	431
Prepaid insurance	993	1,568
Other	1,220	1,119
Total	$ 6,155	$ 7,921

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock Option Activity

The following table summarizes stock option activity under our equity incentive plans during the year ended December 31, 2023:


	Stock Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands) (1)

Outstanding at December 31, 2021	6,757,591	$	8.57	8.7	$	50,085
Options granted	1,409,475	$	8.81
Options exercised	(696,913)	$	2.15
Options cancelled or forfeited	(737,079)	$	11.00
Outstanding at December 31, 2022	6,733,074	$	9.01	8.2	$	8,203
Options granted	3,524,616	$	5.70
Options exercised	(228,264)	$	3.47
Options cancelled or forfeited	(619,022)	$	7.17
Outstanding at December 31, 2023	9,410,404	$	8.03	8.0	$	6,432
Exercisable at December 31, 2023	4,440,139	$	8.06	7.2	$	4,547
Vested and expected to vest at December 31, 2023	9,410,404	$	8.03	8.0	$	6,432

(1) The aggregate intrinsic value is calculated as the difference between the stock option exercise price and the estimated fair value of the underlying common stock at the end of each reporting period referenced above.

Schedule of Estimated Fair Value of Stock Options on the Grant Date Using Black-Scholes Option-Pricing Model

We estimated the fair value of each employee and stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions:


	Years Ended December 31,
	2023	2022
Volatility	74.1% to 75.8%	71.7% to 74.2%
Expected term (in years)	5.0 to 6.0	5.5 to 6.0
Risk-free interest rate	3.5% to 4.9%	1.7% to 4.4%
Expected dividend yield	0.0%	0.0%

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity

A summary of the status of and change in unvested RSUs and PSUs as of December 31, 2023 was as follows:


	Number of Shares Underlying Outstanding RSUs and PSUs	Weighted-Average Grant Date Fair Value per RSU and PSU
Unvested, January 1, 2022	—	$	—
Granted	259,839	10.07
Forfeited	(3,693)	9.90
Unvested, December 31, 2022	256,146	$	10.07
Granted	75,000	5.88
Vested	(78,596)	10.04
Forfeited	(47,193)	10.37
Unvested, December 31, 2023	205,357	$	8.49

Schedule of Stock-Based Compensation Expenses Recorded in the Condensed Consolidated Statements of Operations and Comprehensive Loss

We recorded stock-based compensation expense related to employee equity-based awards grants in our consolidated statements of operations and comprehensive loss as follows (in thousands):


	Years Ended December 31,
	2023		2022
Research and development	$	5,809	$	4,345
General and administrative	7,941		7,371
Total	$	13,750	$	11,716

Schedule of Stock-Based Compensation Expense Related to Equity-Based Awards

The above stock-based compensation expense related to the following equity-based awards (in thousands):


	Years Ended December 31,
	2023		2022
Stock options	$	12,392	$	10,982
ESPP	574		310
RSUs	784		424
Total	$	13,750	$	11,716

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
NOL and tax attributes	$ 51,688	$ 37,120
Accrued expenses and reserve	2,158	1,539
Deferred revenue and expenses	697	7,493
State income taxes	7	7
Capitalized license and patent costs	1,456	1,311
Capitalized research and development cost	37,196	18,462
Lease liabilities	7,098	8,058
Stock-based compensation	4,625	2,921
Total deferred tax assets	104,925	76,911
Valuation allowance	(96,166)	(66,408)	$ (34,521)
Net deferred tax assets	8,759	10,503
Deferred tax liabilities:
Investments in equity securities	(1,948)	(1,713)
Lease right of use assets	(5,808)	(7,037)
Fixed assets	(1,560)	(2,134)
Total deferred tax liabilities	(9,316)	(10,884)
Net deferred tax assets (liabilities)	$ (557)	$ (381)

Description of the Business, Organization, and Liquidity	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business, Organization, and Liquidity	Description of the Business, Organization, and Liquidity Business and Organization Caribou Biosciences, Inc. (“Company” or “we”) is a clinical-stage Clustered Regularly Interspaced Short Palindromic Repeats (“CRISPR”) genome-editing biopharmaceutical company dedicated to developing transformative therapies for patients with devastating diseases. Our genome-editing platform, including our novel chRDNA (CRISPR hybrid RNA-DNA, or “chRDNA,” pronounced “chardonnay”) technology, enables more precise genome editing to develop cell therapies that are armored to improve antitumor activity. We are advancing a pipeline of allogeneic, or off-the-shelf, cell therapies from our chimeric antigen receptor (“CAR”) T (“CAR-T”) cell and CAR-natural killer (“CAR-NK”) cell platforms as readily available therapeutic treatments for patients. We incorporated in October 2011 as a Delaware corporation and are headquartered in Berkeley, California. We have four wholly owned subsidiaries: Antler Holdco, LLC, incorporated in Delaware in April 2019; Microbe Holdco, LLC, incorporated in Delaware in June 2020; Arboreal Holdco, LLC, incorporated in Delaware in November 2020; and Biloba Holdco, LLC, incorporated in Delaware in April 2021. Our wholly owned subsidiaries hold interests in our equity investments and do not have operating activities. Liquidity We have incurred operating losses and negative cash flows from operations since our inception and we had an accumulated deficit of $299.3 million as of December 31, 2023. During the year ended December 31, 2023, we incurred a net loss of $102.1 million and used $93.3 million of cash in operating activities. We expect to continue to incur substantial losses, and our ability to achieve and sustain profitability will depend on the successful development, regulatory approval, and commercialization of our product candidates and on our generation of sufficient revenue to support our cost structure. We may never achieve profitability and, unless and until we do, we will need to continue to raise additional capital. Our management expects that existing cash, cash equivalents, and marketable securities of $372.4 million as of December 31, 2023, will be sufficient to fund our current operating plan for at least the next 12 months from the date of issuance of our consolidated financial statements. In July and August of 2023, we issued and sold a total of 22,115,384 shares of our common stock in an underwritten follow-on public offering for total net proceeds of approximately $134.4 million, which included the full exercise of the underwriters’ right to purchase 2,884,615 additional shares of our common stock. During the year ended December 31, 2023, we sold 168,635 shares of our common stock under the Open Market Sale AgreementSM (“ATM Sales Agreement”) with Jefferies LLC (“Jefferies”), at an average price per share of $7.32 for aggregate gross proceeds of $1.2 million ($1.0 million net of offering expenses). In February 2024, we sold 1,594,171 shares of our common stock under the ATM Sales Agreement, at an average price per share of $7.33 for aggregate gross proceeds of $11.7 million ($11.3 million, net of offering expenses).

Fair Value Measurements and Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements and Fair Value of Financial Instruments

The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1—Quoted prices in active markets for identical assets or liabilities.

Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Assets and liabilities measured at fair value are classified in their entireties based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires our management to make judgments and consider factors specific to the asset or liability.

Our financial instruments consist of Level 1, Level 2, and Level 3 financial instruments. We generally classify our marketable securities as Level 1 or Level 2. Instruments are classified as Level 2 when observable market prices for identical securities that are traded in less active markets are used. When observable market prices for identical securities are not available, such instruments are priced using benchmark curves, benchmarking of like securities, sector groupings, matrix pricing, and valuation models. These valuation models are proprietary to the pricing providers or brokers and incorporate a number of inputs, including in approximate order of priority: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including market research publications. For certain security types, additional inputs may be used, or some of the standard inputs may not be applicable. Evaluators may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs listed are available for use in the evaluation process for each security valuation on any given day. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. No such transfers occurred during the years ended December 31, 2023 and 2022. Level 1 financial instruments are comprised of money market fund investments and U.S. Treasury bills. Level 2 financial instruments are comprised of commercial paper, corporate debt securities, and U.S. government agency bonds. Financial assets and liabilities are considered Level 3 when their fair values are determined using pricing models, discounted cash flow methodologies, or similar techniques, and at least one significant model assumption or input is unobservable. Level 3 financial instruments consist of the MSKCC success payments liability.

The following table sets forth our financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


	Fair Value Measurements as of December 31, 2023
	Total		Level 1		Level 2		Level 3
Assets:
U.S. Treasury bills ($23,527 included in cash and cash equivalents)	$	262,439	$	262,439	$	—	$	—
Commercial paper ($9,759 included in cash and cash equivalents)	40,373		—		40,373		—
U.S. government agency bonds	40,185		—		40,185		—
Money market fund investments (included in cash and cash equivalents)	17,876		17,876		—		—
Corporate debt securities	11,531		—		11,531		—
Total fair value of assets	$	372,404	$	280,315	$	92,089	$	—

Liabilities:
MSKCC success payments liability	$	2,939	$	—	$	—	$	2,939
Total fair value of liabilities	$	2,939	$	—	$	—	$	2,939


	Fair Value Measurements as of December 31, 2022
	Total		Level 1		Level 2		Level 3
Assets:
Commercial paper ($26,669 included in cash and cash equivalents)	$	96,899	$	—	$	96,899	$	—
U.S. Treasury bills	91,966		91,966		—		—
U.S. government agency bonds ($3,976 included in cash and cash equivalents)	63,659		—		63,659		—
Corporate debt securities	36,819		—		36,819		—
Money market fund investments (included in cash and cash equivalents)	27,693		27,693		—		—
Total fair value of assets	$	317,036	$	119,659	$	197,377	$	—

Liabilities:
MSKCC success payments liability	$	1,651	$	—	$	—	$	1,651
Total fair value of liabilities	$	1,651	$	—	$	—	$	1,651

The fair value and amortized cost of cash equivalents and available-for-sale marketable securities by major security type as of December 31, 2023 and 2022 are presented in the following tables (in thousands):


	As of December 31, 2023
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Treasury bills ($23,527 included in cash and cash equivalents)	$	262,328	$	331	$	(220)	$	262,439
Commercial paper ($9,759 included in cash equivalents)	40,386		—		(13)		40,373
U.S. government agency bonds	40,295		1		(111)		40,185
Money market fund investments (included in cash equivalents)	17,876		—		—		17,876
Corporate debt securities	11,489		50		(8)		11,531
Total cash equivalents and marketable securities	$	372,374	$	382	$	(352)	$	372,404

Classified as:
Cash and cash equivalents							$	51,162
Marketable securities, short-term							277,665
Marketable securities, long-term							43,577
Total cash equivalents and marketable securities							$	372,404


	As of December 31, 2022
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Commercial paper ($26,669 included in cash equivalents)	97,024		6		(131)		96,899
U.S. Treasury bills	92,910		1		(945)		91,966
U.S. government agency bonds (3,976 included in cash and cash equivalents)	63,926		25		(292)		63,659
Corporate debt securities	37,002		—		(183)		36,819
Money market fund investments (included in cash equivalents)	$	27,693	$	—	$	—	$	27,693
Total cash equivalents and marketable securities	$	318,555	$	32	$	(1,551)	$	317,036

Classified as:
Cash equivalents							$	58,338
Marketable securities, short-term							189,325
Marketable securities, long-term							69,373
Total cash equivalents and marketable securities							$	317,036

During the years ended December 31, 2023 and 2022, we reviewed our impaired marketable securities and concluded that the decline in fair value was not related to credit losses and is recoverable. Accordingly, no allowance for credit losses was recorded and instead the unrealized losses are reported as a component of accumulated other comprehensive loss.

The following table presents the fair value of available-for-sale marketable securities by contractual maturities (in thousands):


	December 31, 2023
Due in less than one year	$	277,665
Due in one to five years	43,577
Total	$	321,242

The following table sets forth a summary of the changes in the fair value of our Level 3 financial liability (in thousands):


	MSKCC Success Payments Liability
Balance at December 31, 2021	$	4,080
Change in fair value	(2,429)
Balance at December 31, 2022	$	1,651
Change in fair value	1,288
Balance at December 31, 2023	$	2,939

Our liability for the MSKCC success payments is carried at fair value and changes are recognized as expense or income as part of other income (expense) until the success payments liability is paid or expires (Note 4).

The table below summarizes key assumptions used in the valuation of MSKCC success payments liability:


	As of December 31, 2023		As of December 31, 2022
Fair value of common stock	$	5.73	$	6.28
Risk-free interest rate	3.88%		3.88%
Expected volatility	79%		79%
Probability of achieving multiple of Initial Share Price(1)	5.2% to 18.1%		3.0% to 10.6%
Expected term (years)	3.7 to 5.2		4.6 to 6.0

(1)MSKCC is entitled to certain success payments if our common stock fair value increases by certain multiples of value based on a comparison of the fair market value of our common stock to $5.1914 per share, adjusted for any future stock splits (“Initial Share Price”), during a specified time period (Note 4).

The computation of expected volatility was estimated using a combination of available information about the historical volatility of stocks of similar publicly traded companies for a period matching the expected term assumption and the historical and implied volatility of our stock. The risk-free interest rate, expected volatility, and expected term assumptions depend on the initiation of our AMpLify phase 1 clinical trial for our CB-012 product candidate utilizing the know-how, biological materials, and intellectual property licensed under the Exclusive License Agreement, dated November 13, 2020, with MSKCC (“MSKCC Agreement”) and the estimated timing of marketing approval for this product candidate from the U.S. Food and Drug Administration (“FDA”). In addition, we incorporated the estimated number and timing of valuation measurement dates in the calculation of the MSKCC success payments liability.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation and Principles of Consolidation

The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and include our and the accounts of our wholly owned subsidiaries. All intercompany accounts and transactions are eliminated in consolidation.

Use Of Estimates

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities; the disclosure of contingent assets and liabilities at the date of our consolidated financial statements; and the reported amounts of revenue, income, and expenses during the applicable reporting period. On an ongoing basis, we evaluate our estimates and assumptions, including those related to revenue recognition, stock-based compensation expense, accrued expenses related to research

and development activities, valuation of the Memorial Sloan Kettering Cancer Center (“MSKCC”) success payments liability, operating lease right-of-use assets and liabilities, and income taxes. Our management bases its estimates on historical experience and on various other assumptions that they believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.

Segments

We operate and manage our business as one reportable operating segment, which is the business of developing a pipeline of allogeneic CAR-T and CAR-NK cell therapies. Our president and chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for allocating resources and evaluating financial performance. All long-lived assets are maintained in the United States.

Concentration of Credit Risk and Other Uncertainties

Concentrations of Credit Risk and Other Uncertainties

Financial instruments that potentially subject us to concentration of credit risk consist of cash and cash equivalents, accounts receivable, contract assets, other receivables, and investments in marketable securities and equity securities. Substantially all of our cash and cash equivalents are deposited in accounts at three financial institutions, and our account balances exceed federally insured limits. We mitigate the risks by investing in high-grade instruments, limiting our exposure to one issuer, and we monitor the ongoing creditworthiness of the financial institutions and issuers.

Licensees that represent 10% or more of our revenue and accounts receivable and contract assets were as follows:


	Revenue				Accounts Receivable and Contract Assets
	Years Ended December 31,				As of December 31,
	2023		2022		2023		2022
Licensee A	*		16.2	%	47.5	%	23.8	%
Licensee B	71.9	%	57.4	%	*		36.6	%
Total	71.9	%	73.6	%	47.5	%	60.4	%

*Less than 10%

We monitor economic conditions to identify facts or circumstances that may indicate if any of our accounts receivable are not collectible or if the contract assets should be impaired.

Revenue Recognition

We determine whether agreements are within the scope of Accounting Standard Codification (“ASC”) Topic 606, Revenue from contracts with customers (“ASC 606”) or other topics at the effective date of an agreement. For agreements that are determined to be within the scope of ASC 606, revenue is recognized when a licensee, or customer, obtains control of promised goods or services (e.g., an intellectual property license). The amount of revenue recognized reflects the consideration that we expect to be entitled to receive in exchange for these goods and services. To achieve this core principle, we apply the following five steps (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when or as we satisfy a performance obligation.

Our revenues are primarily derived through license and/or license and collaboration agreements. The terms of these types of agreements may include (i) licenses for our technology, (ii) research and development services, and (iii) services or obligations in connection with our participation in research or governance committees. Payments to us under these arrangements typically include one or more of the following: nonrefundable upfront license fees, maintenance fees, milestones, and other contingent payments to us for the achievement of defined collaboration objectives and certain preclinical, clinical, regulatory, and sales-based events, as well as royalties on sales of any commercialized products.

We assess whether the promises in our contracts with third parties are considered distinct performance obligations that should be accounted for separately. Judgment is required to determine whether a license to our intellectual property is distinct from research and development services or participation on research or governance committees.

If a license to intellectual property controlled by us is determined to be distinct from the other performance obligations identified in the agreement, we recognize revenues allocated to the license at the point in time when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are combined with other promises, we utilize our judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. We evaluate the measure of progress using the input method for each reporting period and, if necessary, adjust the measure of performance and related revenue recognition.

Certain of our license agreements include contingent milestone payments. Such milestone payments are typically payable when the collaborator or licensee achieves certain predetermined clinical, regulatory, and/or commercial milestones. Milestone payments that are not within our control or the control of the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At each reporting date, we reevaluate whether the milestones are considered probable of being reached, and we estimate the amount to be included in the transaction price by using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price in such period of determination.

Our license and/or collaboration and license agreements may also include contingent payments related to sales-based milestones. Sales-based milestones are typically payable when annual sales of a covered product reach specified levels. Sales-based milestones are recognized at the later of when the associated performance obligation has been satisfied or when the sales occur. Unlike other contingency payments, such as regulatory milestones, sales-based milestones are not included in the transaction price based on estimates at the inception of the contract, but rather, are included when the sales or usage occur. We use the sales-based royalty exception because the license is a predominant item to which sales-based royalties relate.

Certain of our license agreements have two performance obligations: a license and a material right for annual license renewals. Such license agreements require payments of non-refundable annual license fees by the licensee (referred to as maintenance fees in the license agreements), which are accounted for as material rights for license renewals. We recognize revenue when the license is delivered and the term commences. Revenue for the material right for license renewals is recognized at the point in time that the annual license fee is paid by the licensee and the renewal period begins.

Payments received under third-party contracts are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until we satisfy our performance obligations under these contracts. We record contract assets when payment is due under third-party contracts conditioned on future performance or the occurrence of other events. Amounts payable to us are recorded as accounts receivable if invoiced and if our right to consideration is unconditional.

Fair Value Measurements

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability (Note 3).

Cash and Cash Equivalents

We consider all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. As of December 31, 2023 and 2022, cash and cash equivalents consisted of cash, money market funds, commercial paper securities, and U.S. Treasury bills.

Restricted Cash

Marketable Securities

Our short-term and long-term marketable securities are available for sale securities and consist of U.S. Treasury bills, commercial paper, U.S. government agency bonds, and corporate debt securities. We classify those securities that mature in more than 12 months as long-term investments in the consolidated balance sheets. We record at estimated fair value based on quoted market prices or observable market inputs of almost identical assets, with the unrealized holding gains or losses recorded in other comprehensive loss in the consolidated statements of operations and comprehensive loss. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity, which are both recorded to interest income in the consolidated statements of operations and comprehensive loss. When the fair value of a debt security declines below its amortized cost basis, any portion of that decline attributable to credit losses, to the extent expected to be nonrecoverable before the sale of the security, is recognized in our statement of operations. When the fair value of a debt security declines below its amortized cost basis due to changes in interest rates, such amounts are recorded in other comprehensive loss, and are recognized in our statements of operations only if we sell or intend to sell the security before recovery of its cost basis.

Investments in Equity Securities

We may receive as consideration under our license agreements equity securities of private or public companies (an “investee”). If we determine that we do not have control over these investees under either the Variable Interest Entity (“VIE”) or voting models, we then determine if we have an ability to exercise significant influence via voting interests, board of director representation, or other business relationships. If we conclude that we do not have an ability to exercise significant influence over an investee, we account for our investment at fair value and may elect to account for an equity security without a readily determinable fair value using a measurement alternative. This measurement alternative allows us to measure the equity investment at its cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. If we determine that we do have control over these companies under either voting or VIE models, we consolidate them in our consolidated financial statements.

As of December 31, 2023 and 2022, investments in equity securities, long-term, consisted primarily of our investment in the preferred stock of a private company, related party (Note 7). We concluded that our shares of the private company’s preferred stock are not in substance common stock and, since these securities do not have readily determinable fair value, we account for our investment in the private company’s preferred stock using the measurement alternative method.

Property and Equipment

Property and equipment are recorded at cost, net of accumulated depreciation and amortization. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets.


Computer equipment			3 years
Furniture and office equipment			5 years
Lab equipment			5 years
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Upon retirement or sale of the assets, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is recorded in the statements of operations. Repairs and maintenance are expensed as incurred.

Impairment of Long-Lived Assets

We evaluate the carrying amount of our long-lived assets whenever events or changes in circumstances indicate that the assets may not be recoverable. An impairment loss is recognized when estimated future cash flows expected to result from the use of the asset and its eventual disposition is less than the carrying amount of the asset. To date, there have been no such impairment losses.

Leases

Under Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2016-02, Leases (Topic 842) and its associated amendments, we determine if an arrangement is a lease at inception. In addition, we determine whether a lease meets the classification criteria of a finance or operating lease at the lease commencement date considering whether: (i) the lease transfers ownership of the underlying asset to the lessee at the end of the lease term; (ii) the lease grants the lessee an option to purchase the underlying asset that the lessee is reasonably certain to exercise; (iii) the lease term is for a major part of the remaining economic life of the underlying asset; (iv) the present value of the sum of the lease payments and residual value guaranteed by the lessee equals or exceeds substantially all of the fair value of the underlying asset; and (v) the underlying asset is such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. As of December 31, 2023, our leases consisted of real estate operating leases and we did not have any finance leases.

Operating leases are included in Operating lease right-of-use assets; Operating lease liabilities, current; and Operating lease liabilities, non-current in our consolidated balance sheets. Right-of-use assets represent our right to use the underlying assets for the lease term and lease liabilities represent our obligation to make lease payments arising from the leases. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, if the rate implicit in the lease is not readily determinable, we would use our incremental borrowing rate based on the information available at the lease commencement date. We would determine the incremental borrowing rate based on an analysis of corporate bond yields with a credit rating similar to ours. The determination of our incremental borrowing rate requires management judgment, including development of a synthetic credit rating and cost of debt, as we currently do not carry any debt. We believe that the estimates used in determining the incremental borrowing rate are reasonable based upon facts and circumstances. Applying different judgments to the same facts and circumstances could yield a different incremental borrowing rate. The operating lease right-of-use assets also include adjustments for prepayments and accrued lease payments and exclude lease incentives. Right-of-use assets and lease liabilities may include options to extend or terminate leases if it is reasonably certain that we will exercise such options. Lease payments which are fixed and determinable are amortized as rent and lease expense on a straight-line basis over the expected lease term. Variable lease costs, which are dependent on usage, a rate or index, including common area maintenance charges, are expensed as incurred. Lease agreements that include lease and non-lease components are accounted for as a single lease component. Lease agreements with non-cancelable terms of less than 12 months are not recorded on our balance sheets.

MSKCC Success Payments Liability

Under the terms of our Exclusive License Agreement, dated November 13, 2020, with MSKCC (Note 4), we are obligated to make success payments and a change of control payment if our stock price increases by certain multiples of increasing value based on a comparison of the fair market value of our common stock with $5.1914 per share, adjusted for any future stock splits, during a specified time period. The relevant time period commences when the first patient is dosed with our first CLL-1 product candidate (CB-012) in the first phase 1 clinical trial and ends upon the earlier of the third anniversary of approval of our biologics license application (“BLA”) by the FDA or 10 years from the date the first patient was dosed with our first CLL-1 product candidate in the first phase 1 clinical trial. The success payments liability is accounted for under ASC 815, Derivatives and Hedging. The nature of the success payments liability is contingent consideration for the MSKCC exclusive license and, as such, it was accounted for as research and development expenses at estimated fair value at inception. The success payments liability is remeasured at fair value at each subsequent balance sheet date, and changes in the fair value of the success payments liability are included in other income (expense) in the consolidated statements of operations and comprehensive loss.

To determine the estimated fair value of the MSKCC success payments liability, we use a Monte Carlo simulation methodology that models the future movement of stock prices based on several key variables. This model requires significant estimates and assumptions in determining the estimated fair value of the MSKCC success payments liability at each balance sheet date. The following variables were incorporated in the estimated fair value of the success payments liability: estimated term of the success payments, fair value of common stock, expected volatility, risk-free interest rate, and estimated number and timing of valuation measurement dates on the basis of which payments may be triggered. The computation of expected volatility was estimated using a combination of available information about the historical volatility of stocks of similar publicly traded companies for a period matching the expected term assumption and projected volatility. The assumptions used to calculate the fair value of the MSKCC success payments liability are subject to a significant amount of judgment including the expected volatility that was estimated using available information about the historical volatility of stocks of publicly traded companies that are similar to us, the estimated term, and the estimated

number and timing of valuation measurement dates. There are several valuation measurement dates that may trigger payments under the MSKCC Agreement and are considered in our valuation of the MSKCC success payments liability (Note 4).

Accrued Research and Development Expenses

Research and development expenses are charged to expense as incurred. Research and development expenses include those for certain payroll and personnel; laboratory supplies; consulting; manufacturing; external clinical; and allocated overhead, including rent, equipment depreciation, and utilities.

We record accrued liabilities for estimated costs of our research and development activities conducted by third-party service providers. We record the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and include these costs in accrued liabilities in the consolidated balance sheets and within research and development expenses in the consolidated statements of operations and comprehensive loss. We accrue for these costs based on factors such as estimates of the work completed and in accordance with the third-party service agreements. If we do not identify costs that have begun to be incurred or if we underestimate or overestimate the level of services performed or the costs of these services, actual expenses could differ from our estimates. To date, we have not experienced any material differences between accrued costs and actual costs incurred.

We make payments in connection with clinical trials to contract manufacturing organizations (“CMOs”) that manufacture the material for our product candidates and to clinical research organizations (“CROs”) and clinical trial sites that conduct and manage our clinical trials. The financial terms of these contracts are subject to negotiation, which vary by contract and may result in payments that do not match the periods over which materials or services are provided. Generally, these agreements set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. In the event we make advance payments for goods or services that will be used or rendered for future research and development activities, the payments are deferred and capitalized as a prepaid expense and recognized as expense as the goods are received or the related services are rendered. These payments are evaluated for current or long-term classification based on when they are expected to be realized.

Acquisition of In-Process Research and Development Assets

We measure and recognize acquired in-process research and development assets, which include licenses, know-how, patents, and transaction fees, based on the cost to acquire the assets and the consideration is allocated to the items based on a relative fair value methodology. Goodwill is not recognized in asset acquisitions. If acquired in-process technology is determined to not have an alternative future use, the cost is charged to research and development expenses at the acquisition date.

Patent Costs

We expense patent costs as incurred for filing, prosecuting, and maintaining patents and patent applications, including certain of the patents and patent applications that we license from third parties. We classify these costs as general and administrative expenses in our consolidated statements of operations and comprehensive loss. In addition, we are entitled to receive reimbursement from third parties for a portion of the filing, prosecution, and maintenance costs for certain patents and patent applications. We accrue for these reimbursements as the respective expenses are incurred, and we classify such reimbursements as a reduction of general and administrative expenses. During the years ended December 31, 2023 and 2022, we incurred gross patent costs of $4.3 million and $7.3 million, respectively. During the years ended December 31, 2023 and 2022, we recorded $1.5 million and $3.5 million, respectively, of patent cost reimbursements as a credit to general and administrative expenses.

Stock-Based Compensation Expense

Stock-based compensation expense related to awards to employees is measured at the grant date based on the fair value of the award. We determine the grant-date fair value of the options using the Black-Scholes option-pricing model. The fair value of restricted stock units (“RSUs”) and performance-based RSUs (“PSUs”) awards is determined based on the number of units granted and the closing price of our common stock as of the grant-date. The fair value of the award that is ultimately expected to vest is recognized as expense on a straight-line basis over the requisite service period of the awards, which is generally the vesting period, and is adjusted for pre-vesting forfeitures in the period in which the forfeitures occur.

We use the Black-Scholes valuation model as the method for determining the estimated fair value of stock options and stock purchases under our 2021 Employee Stock Purchase Plan (“ESPP”) with the following assumptions:

Fair Market Value of Common Stock — Prior to our Initial Public Offering (“IPO”), the fair market value of our common stock was determined by our board of directors with assistance from management and external valuation experts. Our approach to estimating the fair market value of our common stock was consistent with the methods outlined in the American Institute of Certified Public Accountants’ Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. Following our IPO, the fair market value of our common stock is based on its closing price on Nasdaq as reported on the date of the stock option grant.

Expected Term — Expected term represents the period that our stock-based awards are expected to be outstanding and is determined using the simplified method. The expected term for our stock purchases under our ESPP is the offering period.

Expected Volatility — Expected volatility is estimated based on the average historical volatilities of common stock of comparable publicly traded entities over a period equal to the expected term of the stock option grants, as we do not have sufficient trading history for our common stock. Comparable companies are chosen based on their size, stage in the life cycle, or area of specialty. We will continue to apply this process for stock options and ESPP stock purchases until enough historical information regarding the volatility of our stock price becomes available.

Expected Dividends — Expected dividends is zero as we have never paid dividends on our common stock and have no plans to do so for the foreseeable future.

Risk-Free Interest Rate — Risk-free interest rate is based on the U.S. Treasury zero-coupon issued in effect at the time of grant for periods corresponding with the expected term of the award.

Income Taxes

We account for income taxes using the asset and liability method. We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Tax benefits related to uncertain tax positions are recognized when it is more likely than not that a tax position will be sustained during an audit. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax.

Other Income, net

We recognize fees earned from sources not considered to be within the normal course of business in other income within the statements of operations and comprehensive loss.

Comprehensive Loss

Comprehensive loss is composed of net loss and other comprehensive income (loss). Other comprehensive income (loss) consists of unrealized gains and losses on available-for-sale marketable securities.

Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of potential dilutive securities. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted-average number of common shares outstanding during the period plus the dilutive effects of potentially dilutive securities outstanding during the period. Potentially dilutive securities include common stock options, RSUs issued and outstanding. For all periods presented, diluted net loss per share is the same as basic net loss per share since the effect of including potential common shares is anti-dilutive.

Recent Accounting Pronouncements and New Accounting Pronouncements Not Yet Adopted

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by FASB or other standard-setting bodies and adopted are by us as of the specified effective date.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326). This ASU provides guidance on the measurement of credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. ASU 2016-13 replaces the current incurred loss impairment approach with a methodology to reflect expected credit losses and requires consideration of a broader range of reasonable and supportable information to explain credit loss estimates. This ASU is to be applied on a modified retrospective approach and is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2022. Early adoption is permitted for all entities for fiscal years beginning after December 15, 2018, and interim periods therein. We adopted ASU 2016-13 on January 1, 2023. The impact of ASU 2016-13 on our financial statements and related disclosures was not material.

New Accounting Pronouncements Not Yet Adopted

In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative. This ASU aligns the requirements in the ASC to the removal of certain disclosure requirements set out in Regulation S-X and Regulation S-K, announced by the U.S. Securities and Exchange Commission (“SEC”). The effective date for each amended topic in the ASC is either the date on which the SEC’s removal of the related disclosure requirement from Regulation S-X or Regulation S-K becomes effective, or on June 30, 2027, if the SEC has not removed the requirements by that date. Early adoption is prohibited. We are currently evaluating the impact of the adoption of this standard.

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This ASU requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. We are currently evaluating the impact of the adoption of this standard.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU requires public entities, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. We are currently evaluating the impact the adoption of this standard.

Emerging Growth Company and Smaller Reporting Company Status

We are an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 Act (“JOBS” Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. We have elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that we (a) are no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, our consolidated financial statements may not be comparable to those of companies that comply with the new or revised accounting pronouncements as of public company effective dates.

We expect to use the extended transition period for any other new or revised accounting standards during the period in which we remain an emerging growth company. We have early adopted certain accounting standards because the JOBS Act does not preclude an emerging growth company from adopting a new or revised accounting standard earlier than the time that such standard applies to private companies to the extent early adoption is allowed by the accounting standard.

We are also a “smaller reporting company.” If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, we may choose to present only the two most

recent fiscal years of audited consolidated financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Common Stock (Tables)

12 Months Ended

Dec. 31, 2023

Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance, consisted of the following:


	As of December 31, 2023	As of December 31, 2022
Stock options, issued and outstanding	9,410,404	6,733,074
Stock options, authorized for future issuance	5,952,012	5,833,979
Stock available under our employee stock purchase plan	1,516,355	1,044,518
Unvested restricted stock units and performance-based restricted stock units	205,357	256,146
Total common stock reserved for future issuance	17,084,128	13,867,717

Net Loss Per Share - Computation of the Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,697,680	7,038,329
Stock options outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,410,404	6,733,074
RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	153,000	256,146
Shares available under ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	134,276	49,109

Fair Value Measurements and Fair Value of Financial Instruments - Contractual Maturity (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Fair Value Disclosures [Abstract]
Due in less than one year	$ 277,665
Due in one to five years	43,577
Total	$ 321,242

Commitment and Contingencies	12 Months Ended
Commitment and Contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Research, Manufacturing, and License Agreements We enter into various agreements in the ordinary course of business, such as those with CMOs, suppliers, CROs, clinical trial sites, licensors, assignors, and the like. These agreements provide for termination by either party in certain circumstances, generally with less than one-year notice and are, therefore, cancellable contracts and, if cancelled, are not anticipated to have a material effect on our consolidated financial condition, results of operations, or cash flows. Some of these agreements include contingent payments that will become payable if and when certain development, regulatory, clinical, and/or commercial milestones are achieved by us. As of December 31, 2023, the satisfaction and timing of such contingent payments is uncertain and is not reasonably estimable. Guarantees and Indemnifications In the normal course of business, we enter into agreements that contain a variety of representations and warranties and provide for certain indemnifications by us. Our exposure under these agreements is unknown because claims may be made against us in the future. To date, we have not paid any claims or been required to defend any action related to our indemnification obligations. As of each of December 31, 2023 and 2022, we did not have any material indemnification claims that were probable or reasonably possible, and consequently, we have not recorded related liabilities. Litigation From time to time, we may become involved in litigation arising in the ordinary course of business. We record a liability for such litigation when it is probable that future losses will be incurred and if such losses can be reasonably estimated. Significant judgment by us is required to determine both probability and the estimated amount. On April 11, 2023, a putative class action lawsuit was filed in the U.S. District Court for the Northern District of California against our company and certain of our officers and current and former members of our board of directors, Bergman v. Caribou Biosciences, Inc., et al., Case Number 4:23-cv-01742-YGR (“Bergman Case”). The Bergman complaint challenges disclosures regarding our company’s business, operations, and prospects, specifically with respect to the alleged durability of CB-010’s therapeutic effect and the product candidate’s clinical and commercial prospects, in alleged violation of Sections 11 and 15 of the Securities Act of 1933, as amended (“Securities Act”) and Sections 10(b) and 20(a) of the Exchange Act. On September 18, 2023, plaintiffs filed an amended complaint adding the IPO underwriters as defendants and making substantially the same allegations as the original complaint. On November 14, 2023, we filed a motion to dismiss the amended complaint for failure to state a claim. Motion to dismiss briefing was completed on February 21, 2024, and oral argument on the motion is scheduled for April 23, 2024. We intend to vigorously defend the claims asserted against us. On March 22, 2023, a putative class action lawsuit was filed in Superior Court of the State of California for the County of Alameda against our company and certain of our officers and current and former members of our board of directors, Lowry v. Caribou Biosciences, Inc., et al., Case Number T23-1084 (“Lowry Case”). The Lowry Case challenges disclosures regarding our company’s business, operations, and prospects, specifically with respect to the alleged durability of CB-010’s therapeutic effect and the product candidate’s clinical and commercial prospects, in alleged violation of Sections 11 and 15 of the Securities Act. The allegations and claims in the Lowry Case are substantially similar to the Securities Act claims asserted in the Bergman Case. On April 26, 2023, we filed a motion to stay the Lowry Case during the pendency of the parallel federal court litigation in the Bergman Case, and, on July 11, 2023, our motion to stay was denied. On September 11, 2023, plaintiff filed an amended complaint making substantially the same allegations as the original complaint. On November 9, 2023, we filed a motion to dismiss the amended complaint on the grounds that our certification of incorporation mandates that Securities Act claims against us be brought in federal court. On February 28, 2024, the court granted our motion to dismiss and ordered the case dismissed.

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Fair Value and Amortized Cost of Cash Equivalents and Available-for-Sale Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis	$ 51,162	$ 58,338
Cash, cash equivalents, and available-for-sale, amortized cost	372,374	318,555
Unrealized Gains	382	32
Unrealized Losses	(352)	(1,551)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value	372,404	317,036
Marketable securities, short-term	277,665	189,325
Marketable securities, long-term	43,577	69,373
U.S. Treasury bills \| Fair Value, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis	23,527
Commercial Paper \| Fair Value, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis	9,759	26,669
US Government Agency Bonds
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis		3,976
US Government Agency Bonds \| Fair Value, Recurring
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis		3,976
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents, amortized cost basis	17,876	27,693
Cash and cash equivalents, estimated fair value	17,876	27,693
U.S. Treasury bills
Debt Securities, Available-for-sale [Line Items]
Cash, cash equivalents, and available-for-sale, amortized cost	262,328
Amortized Cost Basis		92,910
Unrealized Gains	331	1
Unrealized Losses	(220)	(945)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value	262,439
Available for sale, estimated fair value		91,966
Commercial Paper
Debt Securities, Available-for-sale [Line Items]
Cash, cash equivalents, and available-for-sale, amortized cost	40,386	97,024
Unrealized Gains	0	6
Unrealized Losses	(13)	(131)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value	40,373	96,899
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	11,489	37,002
Unrealized Gains	50	0
Unrealized Losses	(8)	(183)
Available for sale, estimated fair value	11,531	36,819
US Government Agency Bonds
Debt Securities, Available-for-sale [Line Items]
Cash, cash equivalents, and available-for-sale, amortized cost		63,926
Amortized Cost Basis	40,295
Unrealized Gains	1	25
Unrealized Losses	(111)	(292)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value		$ 63,659
Available for sale, estimated fair value	$ 40,185

Leases - Summary of Future Minimum Commitments Under Lease Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 3,485
2025	4,475
2026	5,720
2027	5,922
2028	6,122
Thereafter	15,993
Total future undiscounted lease payments	41,717
Less imputed interest	(14,609)
Total discounted lease payments	27,108
Less current portion of lease liability	(1,200)	$ (966)
Noncurrent portion of lease liability	25,908	$ 26,780
Offsets related to incentives expected to be paid in year two	$ 1,000

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning balance	$ 2,799	$ 2,202
Increases related to current year tax positions	1,269	847
Increases related to prior year tax positions	123	0
Decreases related to prior year tax positions	(98)	(250)
Decreases related to lapse of statutes	0
Unrecognized tax benefits, ending balance	$ 4,093	$ 2,799

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2023
Audit Information [Abstract]
Auditor Name	Deloitte & Touche LLP
Auditor Firm Id	34
Auditor Location	San Francisco, California

Common Stock

12 Months Ended

Dec. 31, 2023

Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]

Common Stock

Common stock reserved for future issuance, consisted of the following:


	As of December 31, 2023	As of December 31, 2022
Stock options, issued and outstanding	9,410,404	6,733,074
Stock options, authorized for future issuance	5,952,012	5,833,979
Stock available under our employee stock purchase plan	1,516,355	1,044,518
Unvested restricted stock units and performance-based restricted stock units	205,357	256,146
Total common stock reserved for future issuance	17,084,128	13,867,717

Shelf Registration Statement

On August 9, 2022, we filed a shelf registration statement on Form S-3 (“Shelf Registration Statement”) with the SEC. The Shelf Registration Statement allows us to sell from time to time up to $400.0 million of common stock, preferred stock, debt securities, warrants, rights, or units comprised of any combination of these securities, for our own account in one or more offerings (including the $100.0 million of common stock reserved for our at-the-market equity offering program described below). The SEC declared the Shelf Registration Statement effective on August 16, 2022. The terms of any offering under the Shelf Registration Statement are established at the time of such offering as described in a prospectus supplement to the Shelf Registration Statement filed with the SEC prior to the completion of any such offering.

In July and August 2023, we issued and sold a total of 22,115,384 shares of our common stock in an underwritten follow-on public offering at a price to the public of $6.50 per share, which included the full exercise of the underwriters’ right to purchase 2,884,615 additional shares of our common stock. The total gross proceeds from the offering were approximately $143.7 million ($134.4 million net of underwriting discounts and commissions and offering expenses). The shares were issued pursuant to the Shelf Registration Statement.

At-the-market Equity Offering Program

On August 9, 2022, we entered into an ATM Sales Agreement with Jefferies with respect to an at-the-market (“ATM”) equity offering program, pursuant to which, through Jefferies as sales agent, we may from time to time, sell shares of our common stock having an aggregate offering price of up to $100.0 million in gross proceeds under the Shelf Registration Statement. As of December 31, 2023, we sold 168,635 shares of our common stock under the ATM Sales Agreement at an average price per share of $7.32 for aggregate gross proceeds of $1.2 million ($1.0 million net of offering expenses).

In February 2024, we sold 1,594,171 shares of our common stock under the ATM Sales Agreement, at an average price per share of $7.33 for aggregate gross proceeds of $11.7 million ($11.3 million, net of offering expenses).

Stock-Based Compensation - Restricted Stock Units and Performance-based RSUs (Details) - Restricted Stock Units RSU and Performance-Based RSUs - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Unvested, beginning balance (in shares)	256,146	0
Granted (in shares)	75,000	259,839
Vested (in shares)	(78,596)
Forfeited (in shares)	(47,193)	(3,693)
Unvested, ending balance (in shares)	205,357	256,146
Weighted-Average Grant Date Fair Value per RSU and PSU
Unvested, weighted average grant date fair value per RSU and PSU, beginning balance (in dollars per share)	$ 10.07	$ 0
Granted, weighted average grant date fair value per RSU and PSU (in dollars per share)	5.88	10.07
Vested, weighted-average grant date fair value per RSU and PSU (in dollars per share)	10.04
Forfeited, weighted average grant date fair value per RSU and PSU (in dollars per share)	10.37	9.90
Unvested, weighted average grant date fair value per RSU and PSU, ending balance (in dollars per share)	$ 8.49	$ 10.07

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Licensing and collaboration revenue (including $2,393 and $0, from related parties)	$ 34,477	$ 13,851
Related Party
Licensing and collaboration revenue (including $2,393 and $0, from related parties)	$ 2,393	$ 0

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

Stock-Based Compensation - Schedule of Stock Option Expenses Related to Employee and Non-Employee Stock Options Granted (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 13,750	$ 11,716
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	5,809	4,345
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 7,941	$ 7,371

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred revenue, current	$ 2,847	$ 9,937
Deferred revenue, net of current portion	$ 6,102	$ 15,954
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	88,448,948	61,029,184
Common stock, shares outstanding (in shares)	88,448,948	61,029,184
Related Party
Deferred revenue, current	$ 2,487	$ 150
Deferred revenue, net of current portion	$ 3,730	$ 0

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Reconciliation of Statutory Income Tax Rate to Our Effective Tax Rate

A reconciliation of the U.S. statutory income tax rate to our effective tax rate is as follows:


Years	2023		2022
Federal income tax (benefit) at statutory rate	(21	%)	(21	%)
State taxes, net of federal benefit	(6	%)	(8	%)
Change in valuation allowance, federal	24	%	23	%
Change in valuation allowance, state	6	%	8	%
Stock-based compensation	1	%	—	%
R&D tax credits, net of reserves	(4	%)	(3	%)
Other	—	%	1	%
Effective income tax rate	—	%	—	%

Schedule of Benefit from Income Taxes

For the years ended December 31, 2023 and 2022, our tax provision for (benefit from) income taxes consisted of the following (in thousands):


Years	2023		2022
Current income taxes
Federal	$	—	$	163
State	15		2
Total current income tax expense	15		165

Deferred income taxes:
Federal	1		—
State	177		(95)
Total deferred income tax (benefit) expense	178		(95)
Total income tax expense	$	193	$	70

Schedule of Components of Deferred Tax Assets and Liabilities

The following table presents significant components of our deferred tax assets and liabilities as of December 31, 2023 and 2022 (in thousands):


	2023		2022
Deferred tax assets:
NOL and tax attributes	$	51,688	$	37,120
Accrued expenses and reserve	2,158		1,539
Deferred revenue and expenses	697		7,493
State income taxes	7		7
Capitalized license and patent costs	1,456		1,311
Capitalized research and development cost	37,196		18,462
Lease liabilities	7,098		8,058
Stock-based compensation	4,625		2,921
Total deferred tax assets	104,925		76,911
Valuation allowance	(96,166)		(66,408)
Net deferred tax assets	8,759		10,503
Deferred tax liabilities:
Investments in equity securities	(1,948)		(1,713)
Lease right of use assets	(5,808)		(7,037)
Fixed assets	(1,560)		(2,134)
Total deferred tax liabilities	(9,316)		(10,884)
Net deferred tax assets (liabilities)	$	(557)	$	(381)

Schedule of Unrecognized Tax Benefits

The following table summarizes the activity related to our unrecognized tax benefits for the two years ended December 31, 2023 (in thousands):


Unrecognized tax benefits—December 31, 2021	$	2,202
Increases related to current year tax positions	847
Increases related to prior year tax positions	—
Decreases related to prior year tax positions	(250)
Unrecognized tax benefits—December 31, 2022	2,799
Increases related to current year tax positions	1,269
Increases related to prior year tax positions	123
Decreases related to prior year tax positions	(98)
Decreases related to lapse of statutes	—
Unrecognized tax benefits—December 31, 2023	$	4,093

Summary of Valuation Allowance

The following table shows the change in deferred tax valuation for the periods indicated:


	2023	2022
Beginning balance, January 1	66,408	34,521
Change charged to expense	29,758	31,887
Ending balance, December 31	96,166	66,408

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

We reported pre-tax book losses in the United States of $101.9 million and $99.4 million for the years ended December 31, 2023 and 2022, respectively.

A reconciliation of the U.S. statutory income tax rate to our effective tax rate is as follows:


Years	2023		2022
Federal income tax (benefit) at statutory rate	(21	%)	(21	%)
State taxes, net of federal benefit	(6	%)	(8	%)
Change in valuation allowance, federal	24	%	23	%
Change in valuation allowance, state	6	%	8	%
Stock-based compensation	1	%	—	%
R&D tax credits, net of reserves	(4	%)	(3	%)
Other	—	%	1	%
Effective income tax rate	—	%	—	%

For the years ended December 31, 2023 and 2022, our tax provision for (benefit from) income taxes consisted of the following (in thousands):


Years	2023		2022
Current income taxes
Federal	$	—	$	163
State	15		2
Total current income tax expense	15		165

Deferred income taxes:
Federal	1		—
State	177		(95)
Total deferred income tax (benefit) expense	178		(95)
Total income tax expense	$	193	$	70

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

The following table presents significant components of our deferred tax assets and liabilities as of December 31, 2023 and 2022 (in thousands):


	2023		2022
Deferred tax assets:
NOL and tax attributes	$	51,688	$	37,120
Accrued expenses and reserve	2,158		1,539
Deferred revenue and expenses	697		7,493
State income taxes	7		7
Capitalized license and patent costs	1,456		1,311
Capitalized research and development cost	37,196		18,462
Lease liabilities	7,098		8,058
Stock-based compensation	4,625		2,921
Total deferred tax assets	104,925		76,911
Valuation allowance	(96,166)		(66,408)
Net deferred tax assets	8,759		10,503
Deferred tax liabilities:
Investments in equity securities	(1,948)		(1,713)
Lease right of use assets	(5,808)		(7,037)
Fixed assets	(1,560)		(2,134)
Total deferred tax liabilities	(9,316)		(10,884)
Net deferred tax assets (liabilities)	$	(557)	$	(381)

We have evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. As of December 31, 2022, a valuation allowance of $66.4 million was recorded against our deferred tax assets. As of December 31, 2023, our deferred tax assets were primarily the result of historical federal and state net operating loss (“NOL”) and tax credits, deferred revenue and expenses, capitalized research costs and the net of lease right of use assets and liabilities. As of December 31, 2023, a valuation allowance of $96.2 million was recorded against our deferred tax assets.

As of December 31, 2023, we had federal NOL carryforwards of $103.8 million, which do not expire. As of December 31, 2023, we had state NOL carryforwards of $172.7 million, which may be available to offset future state income, and which expire at various years beginning with 2036.

As of December 31, 2023, we generated federal tax credit carryforwards of $14.2 million, which will begin to expire in 2037. As of December 31, 2023, we had state credit carryforwards of $5.6 million available to reduce future tax liabilities, which do not expire.

Beginning January 1, 2022, the Tax Cuts and Jobs Act of 2017 eliminated the option to deduct research and development expenditures in the current year and requires taxpayers to capitalize and amortize pursuant to Section 174 of the Tax Code. As a result, we have capitalized research and development costs of $102.6 million and $93.9 million for the years ended December 31, 2023 and 2022, respectively. We will amortize these costs for tax purposes over five years if the research and development was performed in the United States and over 15 years if the research and development was performed outside the United States.

Under Section 382 of the Tax Code, the ability to utilize NOL carryforwards or other tax attributes, such as research tax credits, in any taxable year may be limited if we have experienced an “ownership change.” Generally, a Section 382 ownership change occurs if there is a cumulative increase of more than 50 percentage points in the stock ownership of one or more stockholders or groups of stockholders who own at least 5% of a corporation’s stock within a specified testing period. Similar rules may apply under state tax laws. As a result of our analysis, we believe that there have been three ownership changes under Section 382; however, none of our tax attributes are expected to have permanent limitations. We may experience ownership changes as a result of future financing or other changes in the stock ownership.

The following table summarizes the activity related to our unrecognized tax benefits for the two years ended December 31, 2023 (in thousands):


Unrecognized tax benefits—December 31, 2021	$	2,202
Increases related to current year tax positions	847
Increases related to prior year tax positions	—
Decreases related to prior year tax positions	(250)
Unrecognized tax benefits—December 31, 2022	2,799
Increases related to current year tax positions	1,269
Increases related to prior year tax positions	123
Decreases related to prior year tax positions	(98)
Decreases related to lapse of statutes	—
Unrecognized tax benefits—December 31, 2023	$	4,093

As of December 31, 2023, no amount of unrecognized tax benefits, if recognized, would affect the effective tax rate. We do not expect a significant change to our unrecognized tax benefits over the next 12 months. The unrecognized tax benefits may increase or change during the next year for items that arise in the ordinary course of business.

We recognize interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2023 and 2022, we had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in our consolidated statements of operations and comprehensive loss.

We file our federal and state income tax returns with varying statutes of limitations. Our tax years from 2012 through 2022 will remain open to examination due to the carryover of the unused NOLs and tax credits. There are no ongoing examinations by taxing authorities at this time.

The following table shows the change in deferred tax valuation for the periods indicated:


	2023	2022
Beginning balance, January 1	66,408	34,521
Change charged to expense	29,758	31,887
Ending balance, December 31	96,166	66,408

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Stock-Based Compensation - Schedule of Stock-based Compensation Expense Related to Equity-Based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 13,750	$ 11,716
Stock options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	12,392	10,982
ESPP
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	574	310
RSUs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 784	$ 424

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

Use of Estimates

Segments

Concentrations of Credit Risk and Other Uncertainties

Licensees that represent 10% or more of our revenue and accounts receivable and contract assets were as follows:


	Revenue				Accounts Receivable and Contract Assets
	Years Ended December 31,				As of December 31,
	2023		2022		2023		2022
Licensee A	*		16.2	%	47.5	%	23.8	%
Licensee B	71.9	%	57.4	%	*		36.6	%
Total	71.9	%	73.6	%	47.5	%	60.4	%

*Less than 10%

We monitor economic conditions to identify facts or circumstances that may indicate if any of our accounts receivable are not collectible or if the contract assets should be impaired. No allowance for credit losses or contract asset impairment was recorded as of December 31, 2023 or 2022.

Revenue Recognition

Fair Value Measurements

Cash and Cash Equivalents

Restricted Cash

We define restricted cash as cash and cash equivalents that cannot be withdrawn or used for general operating activities. Our restricted cash consists of a letter of credit with a financial institution related to one of our workers’ compensation insurance policies. As of December 31, 2023 and 2022, we had less than $0.1 million of restricted cash, which was recorded in other assets in our consolidated balance sheets.

Marketable Securities

Investments in Equity Securities

Property and Equipment


Computer equipment			3 years
Furniture and office equipment			5 years
Lab equipment			5 years
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Impairment of Long-Lived Assets

Leases

MSKCC Success Payments Liability

Accrued Research and Development Expenses

Acquisition of In-Process Research and Development Assets

Patent Costs

Stock-Based Compensation Expense

Expected Dividends — Expected dividends is zero as we have never paid dividends on our common stock and have no plans to do so for the foreseeable future.

Risk-Free Interest Rate — Risk-free interest rate is based on the U.S. Treasury zero-coupon issued in effect at the time of grant for periods corresponding with the expected term of the award.

Income Taxes

Other Income, net

We recognize fees earned from sources not considered to be within the normal course of business in other income within the statements of operations and comprehensive loss. During the years ended December 31, 2023 and 2022, we recognized $15.3 million and $4.6 million of interest income from our short-term and long-term marketable securities, respectively.

Comprehensive Loss

Net Loss Per Share

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued by FASB or other standard-setting bodies and adopted are by us as of the specified effective date.

New Accounting Pronouncements Not Yet Adopted

Emerging Growth Company and Smaller Reporting Company Status

Stock-Based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stock Options
Outstanding, Beginning balance (in shares)	6,733,074	6,757,591
Options granted (in shares)	3,524,616	1,409,475
Options exercised (in shares)	(228,264)	(696,913)
Options cancelled or forfeited (in shares)	(619,022)	(737,079)
Outstanding, Ending balance (in shares)	9,410,404	6,733,074	6,757,591
Exercisable at end of period (in shares)	4,440,139
Vested and expected to vest at end of period (in shares)	9,410,404
Weighted- Average Exercise Price
Outstanding, Beginning balance (in dollars per shares)	$ 9.01	$ 8.57
Options granted (in dollars per shares)	5.70	8.81
Options exercised (in dollars per shares)	3.47	2.15
Options cancelled or forfeited (in dollars per shares)	7.17	11.00
Outstanding, Ending balance (in dollars per shares)	8.03	$ 9.01	$ 8.57
Exercisable at end of period (in dollars per shares)	8.06
Vested and expected to vest at end of period (in dollars per shares)	$ 8.03
Weighted- Average Remaining Contractual Term (years)
Outstanding	8 years	8 years 2 months 12 days	8 years 8 months 12 days
Exercisable at end of period	7 years 2 months 12 days
Vested and expected to vest at end of period	8 years
Aggregate Intrinsic Value
Outstanding	$ 6,432	$ 8,203	$ 50,085
Exercisable at end of period	4,547
Vested and expected to vest at end of period	$ 6,432

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

Equity Incentive Plans

In July 2021, our board of directors adopted and our stockholders approved the 2021 Equity Incentive Plan (“2021 Plan”) that became effective on July 22, 2021. We reserved 5,200,000 shares of common stock for issuance under the 2021 Plan. In addition, 934,562 shares available for issuance under the 2013 Equity Incentive Plan, adopted in 2013 and amended and restated in 2019, were transferred into the 2021 Plan. In addition, any shares subject to awards under the 2013 Plan that terminate, expire, or lapse for any reason without the delivery of shares, or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price, will be added to the 2021 Plan. The 2021 Plan also provides that the number of shares initially reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2022 and ending on January 1, 2031, by an amount equal to the lesser of (a) 5% of the shares of common stock outstanding on the last day of the immediately preceding fiscal year, and (b) such smaller number of shares of stock as determined by our board of directors. No more than 56,000,000 shares of stock may be issued upon the exercise of incentive stock options under the 2021 Plan. Options under the 2021 Plan may be granted for periods of up to 10 years at exercise prices no less than the fair market value of our common stock on the date of grant; provided, however, that the exercise price of an incentive stock option granted to a 10% stockholder may not be less than 110% of the fair market value of the shares on the date of grant and such option may not be exercisable after the expiration of five years from the date of grant. The grant date fair market value of all awards made under the 2021 Plan and all cash compensation paid by us to any non-employee director for services as a director in any fiscal year may not exceed $750,000, increased to $1,000,000 in the fiscal year of their initial service as a non-employee director. As of December 31, 2023, we had 5,952,012 shares available for issuance under the 2021 Plan.

The following table summarizes stock option activity under our equity incentive plans during the year ended December 31, 2023:


	Stock Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands) (1)

Outstanding at December 31, 2021	6,757,591	$	8.57	8.7	$	50,085
Options granted	1,409,475	$	8.81
Options exercised	(696,913)	$	2.15
Options cancelled or forfeited	(737,079)	$	11.00
Outstanding at December 31, 2022	6,733,074	$	9.01	8.2	$	8,203
Options granted	3,524,616	$	5.70
Options exercised	(228,264)	$	3.47
Options cancelled or forfeited	(619,022)	$	7.17
Outstanding at December 31, 2023	9,410,404	$	8.03	8.0	$	6,432
Exercisable at December 31, 2023	4,440,139	$	8.06	7.2	$	4,547
Vested and expected to vest at December 31, 2023	9,410,404	$	8.03	8.0	$	6,432

Grant Date Fair Value

During the year ended December 31, 2023, we granted 3,524,616 stock options to employees with a weighted-average grant date fair value of $3.88.

During the year ended December 31, 2022, we granted 1,409,475 stock options to employees with a weighted-average grant date fair value of $5.82.

We estimated the fair value of each employee and stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions:


	Years Ended December 31,
	2023	2022
Volatility	74.1% to 75.8%	71.7% to 74.2%
Expected term (in years)	5.0 to 6.0	5.5 to 6.0
Risk-free interest rate	3.5% to 4.9%	1.7% to 4.4%
Expected dividend yield	0.0%	0.0%

As of December 31, 2023, there was $25.8 million of unrecognized stock-based compensation expense related to employee and stock options that is expected to be recognized over a weighted-average period of 2.5 years.

Restricted Stock Units

During the year ended December 31, 2023, we granted 75,000 RSUs and no PSUs under the 2021 Plan. A summary of the status of and change in unvested RSUs and PSUs as of December 31, 2023 was as follows:


	Number of Shares Underlying Outstanding RSUs and PSUs	Weighted-Average Grant Date Fair Value per RSU and PSU
Unvested, January 1, 2022	—	$	—
Granted	259,839	10.07
Forfeited	(3,693)	9.90
Unvested, December 31, 2022	256,146	$	10.07
Granted	75,000	5.88
Vested	(78,596)	10.04
Forfeited	(47,193)	10.37
Unvested, December 31, 2023	205,357	$	8.49

The PSUs were granted to our executive officers and will vest contingent upon the achievement of a clinical milestone for CB-010 during a performance period ending December 31, 2024, and an executive officer’s continued employment during the performance period. As of December 31, 2023, the achievement of this milestone was not considered probable and, therefore, no stock-based compensation was recorded.

As of December 31, 2023, the total unrecognized stock-based compensation expense related to unvested RSUs was $0.8 million, which is expected to be recognized over the remaining weighted-average vesting period of one years. As of December 31, 2023, there was approximately $0.6 million of unrecognized stock-based compensation expense related to unvested PSUs.

Employee Stock Purchase Plan (“ESPP”)

In July 2021, our board of directors adopted and our stockholders approved the ESPP, which became effective on July 22, 2021. The ESPP is intended to qualify as an employee stock purchase plan under Section 423 of the Internal Revenue Code of 1986, as amended (“Tax Code”). We reserved 511,000 shares of our common stock for employee purchases under the ESPP. The number of shares of common stock reserved for issuance under the ESPP will be automatically increased each January 1, beginning on January 1, 2022 and ending on January 1, 2031 by an amount equal to the lesser of (a) 1% of the shares of common stock outstanding on the last day of the immediately preceding fiscal year, and (b) such smaller number of shares of stock as determined by our board of directors; provided that the maximum number of shares that may be issued under the ESPP is 10,000,000 shares. The ESPP allows an eligible employee to purchase shares of our common stock at a discount through payroll deductions of up to 15% of the employee’s eligible compensation. At the end of each purchase period, employees are able to purchase shares at 85% of the lower of the fair market value of our common stock at the beginning of the offering period or at the end of each applicable offering period.

We issued 207,567 shares of common stock under the ESPP as of December 31, 2023. We recorded $0.5 million and $0.3 million in accrued liabilities related to contributions withheld as of December 31, 2023 and December 31, 2022, respectively.

Stock-Based Compensation Expense

We recorded stock-based compensation expense related to employee equity-based awards grants in our consolidated statements of operations and comprehensive loss as follows (in thousands):


	Years Ended December 31,
	2023		2022
Research and development	$	5,809	$	4,345
General and administrative	7,941		7,371
Total	$	13,750	$	11,716

The above stock-based compensation expense related to the following equity-based awards (in thousands):


	Years Ended December 31,
	2023		2022
Stock options	$	12,392	$	10,982
ESPP	574		310
RSUs	784		424
Total	$	13,750	$	11,716

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net loss	$ (102,070)	$ (99,421)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-7

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Significant Agreements - Additional Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Jun. 16, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2023 USD ($) agreement $ / shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 13, 2020 USD ($)	Dec. 15, 2016	Jul. 13, 2015 USD ($)	Jul. 16, 2014
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
General and administrative			$ 38,461	$ 38,020
Revenue recognized included in the opening contract liabilities balance			23,200	5,000
Deferred revenue, current			2,847	9,937
Deferred revenue, net of current portion			6,102	15,954
Revenue			34,477	13,851
Accounts receivable			148	202
Contract assets			1,425	2,247
Contract Assets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract assets			0	900
The Regents of the University of California/University of Vienna
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Clinical milestone payment			$ 3,400
Percentage of sublicensing revenues			0.50
Number of sublicensing agreements \| agreement			25
Reimbursement percentage							50.00%
Reduction in general and administrative expenses			$ 1,100	2,700
The Regents of the University of California/University of Vienna \| Research and development
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicensing expenses			1,600	1,100
The Regents of the University of California/University of Vienna \| General and administrative
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Patent prosecution and maintenance costs			2,300	5,400
Memorial Sloan Kettering Cancer Center
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment fee						$ 500
Commercial milestones						112,000
Aggregate success payment			35,000
Maximum value of success payments and control payment			35,000
Fair value of success payments liability			$ 2,900	1,700
Memorial Sloan Kettering Cancer Center \| Series B Convertible Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Share price (in dollars per share) \| $ / shares			$ 5.1914
Memorial Sloan Kettering Cancer Center \| Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment fee						$ 2,100
Intellia Therapeutics, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment fee	$ 1,000
Percentage of other party's expenses									30.00%
General and administrative			$ 100	100
Potential future milestone payments	$ 23,000
Intellia Therapeutics, Inc. \| Patents
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
General and administrative			400	800
Pioneer Hi-Bred International, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future contingent milestone payments								$ 22,400
Upfront cash payment		$ 500
Pioneer Hi-Bred International, Inc. \| Regulatory Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payment		2,800
Pioneer Hi-Bred International, Inc. \| Sales Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payment		$ 20,000
Pioneer Hi-Bred International, Inc. \| Research and development
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicensing expenses			0	100
Collaboration and License Agreement with AbbVie
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront cash payment received					$ 30,000
Revenue recognized included in the opening contract liabilities balance			22,700
Deferred revenue, current			0	9,400
Deferred revenue, net of current portion			0	13,300
Revenue			24,800	8,000
Accounts receivable			0	$ 0
Collaboration and License Agreement with AbbVie \| Preclinical Research And Development Services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized included in the opening contract liabilities balance			$ 20,800

Common Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	2 Months Ended	12 Months Ended
	Aug. 09, 2022	Feb. 29, 2024	Aug. 31, 2023	Dec. 31, 2023
Subsidiary, Sale of Stock [Line Items]
Authorized amount under shelf registration	$ 400.0
Public Stock Offering
Subsidiary, Sale of Stock [Line Items]
Consideration received on transaction			$ 134.4
Sale of stock, number of shares issued in transaction (in shares)			22,115,384
Public offering price (in dollars per share)			$ 6.50
Sale of stock aggregate gross proceeds			$ 143.7
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)			2,884,615
At The Market ATM Offering
Subsidiary, Sale of Stock [Line Items]
Consideration received on transaction				$ 1.0
Sale of stock, number of shares issued in transaction (in shares)				168,635
Public offering price (in dollars per share)				$ 7.32
Sale of stock aggregate gross proceeds				$ 1.2
At The Market ATM Offering \| Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Consideration received on transaction		$ 11.3
Sale of stock, number of shares issued in transaction (in shares)		1,594,171
Public offering price (in dollars per share)		$ 7.33
Sale of stock aggregate gross proceeds		$ 11.7
At The Market ATM Offering \| Maximum
Subsidiary, Sale of Stock [Line Items]
Consideration received on transaction	$ 100.0

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

Operating Lease Obligations

We lease laboratory and office space under noncancellable operating agreements. In March 2021, we entered into a ten-year lease agreement, which superseded and replaced our prior lease, as amended, for our corporate headquarters and the new lease included additional office and laboratory space located within the same building in Berkeley, California. This lease agreement contains a renewal option for an additional term of five years. In addition to base rent, we pay our share of operating expenses and taxes.

In January 2022, we entered into a ten-and-a-half-year lease agreement for approximately 10,000 square feet of office and laboratory space in Berkeley, California, near our current corporate headquarters. In connection with signing this lease, we paid a deposit in the amount of $0.4 million to the lessor. This lease agreement contains an escalation clause for increased base rent over the term and a renewal option for an additional term of five years. In addition to base rent, we pay our share of operating expenses and taxes. To complete certain leasehold improvements, the lessor has agreed to provide us a tenant improvement allowance of $1.8 million. The leasehold improvements constructed are presented under property and equipment on our consolidated balance sheets and are depreciated on a straight-line basis over the shorter of remaining lease term or estimated useful life.

The components of lease costs, which are included in our statements of operations and comprehensive loss, were as follows (in thousands):


	Years Ended December 31,
	2023		2022
Operating lease cost(1)	$	7,628	$	7,337
Short-term lease cost	250		83
Total lease cost	$	7,878	$	7,420

(1)Includes $2.5 million and $2.2 million of variable lease cost related to operating expenses and taxes for the years ended December 31, 2023, and 2022, respectively.

Supplemental information related to our leases was as follows (in thousands):


	Years Ended December 31,
	2023		2022
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	3,732	$	3,468

The following table summarizes the weighted-average remaining lease term and weighted-average discount rate for our corporate laboratory and office leases:


	Years Ended December 31,
	2023		2022
Weighted-average remaining lease term (years)	7.4		8.3
Weighted-average discount rate	11.3	%	11.3	%

The following table summarizes a maturity analysis of our operating lease liabilities showing the aggregate lease payments as of December 31, 2023:


Year ending December 31:	(in thousands)
2024(1)	$	3,485
2025	4,475
2026	5,720
2027	5,922
2028	6,122
Thereafter	15,993
Total future undiscounted lease payments	41,717
Less imputed interest	(14,609)
Total discounted lease payments	27,108
Less current portion of lease liability	(1,200)
Noncurrent portion of lease liability	$	25,908

(1)Reflects an offset of $1.0 million related to incentives expected to be received in 2024.

Net Loss Per Share - Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (102,070)	$ (99,421)
Denominator:
Weighted average common shares outstanding used to compute net loss per share, basic (in shares)	73,807,597	60,801,133
Weighted average common shares outstanding used to compute net loss per share, diluted (in shares)	73,807,597	60,801,133
Net loss per share, basic (in dollars per share)	$ (1.38)	$ (1.64)
Net loss per share, diluted (in dollars per share)	$ (1.38)	$ (1.64)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-10

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Leases - Additional Information (Details) $ in Millions	12 Months Ended
Leases - Additional Information (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022	Jan. 31, 2022 USD ($) ft²	Mar. 31, 2021
Leases [Abstract]
Lease initial term			10 years 5 months	10 years
Lease renewal term			5 years	5 years
Area of real estate property \| ft²			10,000
Security deposit			$ 0.4
Rent expense	$ 1.8
Weighted-average remaining lease term (years)	7 years 4 months 24 days	8 years 3 months 18 days

401(k) Savings Plan - Additional Information (Details) - 2017 Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution percent of match	4.00%
Employer contribution	$ 1.1	$ 0.7

Subsequent Events - Narrative (Details) - At The Market ATM Offering $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) shares
Subsequent Event [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares	168,635
Sale of stock aggregate gross proceeds	$ 1.2
Consideration received on transaction	$ 1.0

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Basic and Diluted Net Income Per Share

The following table sets forth the computation of the basic and diluted net loss per share (in thousands, except share and per share amounts):


	Years Ended December 31,
	2023		2022
Numerator:
Net loss	$	(102,070)	$	(99,421)
Denominator:
Weighted-average common shares outstanding used to compute net loss per share, basic and diluted	73,807,597		60,801,133
Net loss per share, basic and diluted	$	(1.38)	$	(1.64)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:


	As of December 31, 2023	As of December 31, 2022
Stock options outstanding	9,410,404	6,733,074
RSUs issued and outstanding	153,000	256,146
Shares available under ESPP	134,276	49,109
	9,697,680	7,038,329

Balance Sheet Items - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued employee compensation and related expenses	$ 9,517	$ 5,752
Accrued research and development expenses	8,720	6,731
Accrued patent expenses	613	1,331
Accrued expenses related to sublicensing revenues	802	596
Credit card liability	377	299
Other	1,106	1,370
Total	$ 21,135	$ 16,079

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In February 2024, we sold 1,594,171 shares of our common stock under the ATM Sales Agreement, at an average price per share of $7.33 for aggregate gross proceeds of $11.7 million ($11.3 million, net of offering expenses). On February 28, 2024, the Superior Court of the State of California for the County of Alameda granted our motion to dismiss the putative class action lawsuit filed against our company and certain of our officers and current and former members of our board of directors, Lowry v. Caribou Biosciences, Inc., et al., Case Number T23-1084 (“Lowry Case”), and the court ordered the case dismissed.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 51,162	$ 58,338
Marketable securities, short-term	277,665	189,325
Accounts receivable	148	202
Contract assets	1,425	2,247
Other receivables	2,286	2,215
Prepaid expenses and other current assets	6,155	7,921
Total current assets	338,841	260,248
NON-CURRENT ASSETS
Investments in equity securities	7,753	7,698
Marketable securities, long-term	43,577	69,373
Property and equipment, net	18,270	10,678
Operating lease, right of use assets	22,182	24,230
Other assets	1,586	1,538
TOTAL ASSETS	432,209	373,765
CURRENT LIABILITIES:
Accounts payable	3,120	1,146
Accrued expenses and other current liabilities	21,135	16,079
Operating lease liabilities, current	1,200	966
Deferred revenue ($2,487 and $150 from related party, respectively)	2,847	9,937
Total current liabilities	28,302	28,128
LONG-TERM LIABILITIES
Deferred revenue, net of current portion ($3,730 and $0 from related party, respectively)	6,102	15,954
MSKCC success payments liability	2,939	1,651
Operating lease liabilities, non-current	25,908	26,780
Deferred tax liabilities	557	381
Total liabilities	63,808	72,894
COMMITMENTS AND CONTINGENCIES (Note 9)
STOCKHOLDERS’ EQUITY
Common stock, par value $0.0001 per share, 300,000,000 shares authorized at December 31, 2023 and 2022, respectively; 88,448,948 and 61,029,184 shares issued and outstanding at December 31, 2023 and 2022, respectively	8	6
Additional paid-in-capital	667,648	499,598
Accumulated other comprehensive income (loss)	30	(1,518)
Accumulated deficit	(299,285)	(197,215)
Total stockholders’ equity	368,401	300,871
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 432,209	$ 373,765

Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2023	Mar. 05, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-40631
Entity Registrant Name	Caribou Biosciences, Inc.
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	45-3728228
Entity Address Address Line1	2929 7th Street
Entity Address, Address Line Two	Suite 105
Entity Address City Or Town	Berkeley
Entity Address, State and Province	CA
Entity Address Postal Zip Code	94710
City Area Code	510
Local Phone Number	982-6030
Security12b Title	Common Stock, par value $0.0001 per share
Trading Symbol	CRBU
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 263.4
Entity Common Stock, Shares Outstanding		90,314,501
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s definitive proxy statement for the 2024 Annual Meeting of Stockholders are incorporated by reference into Part III.
Entity Central Index Key	0001619856
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) segment $ / shares	Dec. 31, 2022 USD ($) $ / shares	Jun. 30, 2023 $ / shares	Nov. 13, 2020 $ / shares
Concentration Risk [Line Items]
Number of operating segment \| segment	1
Allowance for doubtful accounts	$ 0	$ 0
Restricted cash (less than)	$ 100,000	$ 100,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001	$ 0.0001	$ 0.0001	$ 5.1914
Patent costs gross	$ 4,300,000	$ 7,300,000
Dividends	0
Other income	15,300,000	4,600,000
General and administrative
Concentration Risk [Line Items]
Patent cost reimbursements	$ 1,500,000	$ 3,500,000

Revenue

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Revenue

Disaggregation of Revenue

We disaggregate revenue by geographical market based on the location of research and development activities of our licensees and collaborators. The following table is a summary of revenue by geographic location for the years ended December 31, 2023 and 2022, (in thousands):


	Years Ended December 31,
	2023		2022
United States	$	32,770	$	13,303
Rest of world	1,707		548
Total	$	34,477	$	13,851

During the year ended December 31, 2023, we recognized $8.4 million of revenue related to performance obligations satisfied at a point in time, and we recognized $26.1 million of revenue related to performance obligations satisfied over time that included $24.8 million in licensing and collaboration revenue associated with the AbbVie Agreement, of which $22.7 million had been included in deferred revenue as of the beginning of the period.

During the year ended December 31, 2022, we recognized $5.9 million of revenue related to performance obligations satisfied at a point in time, and we recognized $8.0 million of revenue related to performance obligations satisfied over time.

Contract Balances

Accounts receivable relate to our right to consideration for performance obligations completed (or partially completed) for which we have an unconditional right to consideration. Our accounts receivable balances represent amounts that we billed to our licensees with invoices outstanding as of the end of a reporting period.

Contract assets are rights to consideration in exchange for a license that we have granted to a licensee when the right is conditional on something other than the passage of time. Our contract asset balances represent reimbursable research costs related to the AbbVie Agreement, as well as royalties and milestone payments from our other license agreements that are unbilled as of the end of a reporting period.

Contract liabilities consist of deferred revenue and relate to amounts invoiced to, or advance consideration received from, licensees that precede our satisfaction of the associated performance obligations. As of December 31, 2023, our deferred revenue balance primarily resulted from the upfront payment received relating to our performance obligation to Pfizer, Inc. (“Pfizer”). As of December 31, 2022 our deferred revenue balance primarily result from the upfront payment received relating to our performance obligations under the now-terminated AbbVie Agreement. The remaining deferred revenue relates to upfront payments received under license agreements that also include nonrefundable annual license fees, which are accounted for as material rights for license renewals and are recognized at the point in time annual license fees are paid by the licensees and the renewal periods begin.

The following table presents changes in our contract assets and liabilities during the year ended December 31, 2023 (in thousands):


	Balance as of December 31, 2022		Additions		Deductions		Balance as of December 31, 2023
Accounts receivable	$	202	$	10,819	$	(10,873)	$	148

Contract assets:
Unbilled accounts receivable	$	2,247	$	6,006	$	(6,828)	$	1,425

Contract liabilities:
Deferred revenue, current and long-term	$	25,891	$	12,981	$	(29,923)	$	8,949

Unbilled accounts receivable decreased during the year ended December 31, 2023, primarily due to the decrease in unbilled research costs under the AbbVie Agreement.

Deferred revenue decreased during the year ended December 31, 2023, primarily due to the recognition of deferred revenues related to the satisfaction of our performance obligation to AbbVie as a result of AbbVie’s termination of the AbbVie Agreement, offset by the $7.5 million allocated to the Pfizer information sharing committee (Notes 4 and 7).

During the years ended December 31, 2023 and 2022, we recognized $23.2 million and $5.0 million of revenue, respectively, which was included in the opening contract liabilities balances at the beginning of the respective periods.

Transaction Prices Allocated to Remaining Performance Obligations

Remaining performance obligations represent in aggregate the amount of a transaction price that has been allocated to performance obligations not delivered as of the end of a reporting period. The value of transaction prices allocated to remaining unsatisfied performance obligations as of December 31, 2023 and 2022 were approximately $8.9 million and $40.4 million, respectively. We expect to recognize approximately $2.8 million of remaining performance obligations as revenue in the next 12 months and to recognize the remainder thereafter.

Capitalized Contract Acquisition Costs and Fulfillment Costs

We did not incur any expenses to obtain license and collaboration agreements, and costs to fulfill those contracts do not generate or enhance our resources. As such, no costs to obtain or fulfill a contract have been capitalized in any period.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Balance Sheet Items - Schedule of Property And Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 27,414	$ 16,327
Less accumulated depreciation and amortization	(9,144)	(5,649)
Property and equipment, net	18,270	10,678
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	15,581	12,588
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	2,235	1,876
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	895	709
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	499	161
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,204	$ 993

Fair Value Measurements and Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Financial Instruments Measured on Recurring Basis

The following table sets forth our financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


	Fair Value Measurements as of December 31, 2023
	Total		Level 1		Level 2		Level 3
Assets:
U.S. Treasury bills ($23,527 included in cash and cash equivalents)	$	262,439	$	262,439	$	—	$	—
Commercial paper ($9,759 included in cash and cash equivalents)	40,373		—		40,373		—
U.S. government agency bonds	40,185		—		40,185		—
Money market fund investments (included in cash and cash equivalents)	17,876		17,876		—		—
Corporate debt securities	11,531		—		11,531		—
Total fair value of assets	$	372,404	$	280,315	$	92,089	$	—

Liabilities:
MSKCC success payments liability	$	2,939	$	—	$	—	$	2,939
Total fair value of liabilities	$	2,939	$	—	$	—	$	2,939


	Fair Value Measurements as of December 31, 2022
	Total		Level 1		Level 2		Level 3
Assets:
Commercial paper ($26,669 included in cash and cash equivalents)	$	96,899	$	—	$	96,899	$	—
U.S. Treasury bills	91,966		91,966		—		—
U.S. government agency bonds ($3,976 included in cash and cash equivalents)	63,659		—		63,659		—
Corporate debt securities	36,819		—		36,819		—
Money market fund investments (included in cash and cash equivalents)	27,693		27,693		—		—
Total fair value of assets	$	317,036	$	119,659	$	197,377	$	—

Liabilities:
MSKCC success payments liability	$	1,651	$	—	$	—	$	1,651
Total fair value of liabilities	$	1,651	$	—	$	—	$	1,651

Schedule of Fair Value and Amortized Cost of Cash Equivalents and Available-for-Sale Marketable Securities


	As of December 31, 2023
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
U.S. Treasury bills ($23,527 included in cash and cash equivalents)	$	262,328	$	331	$	(220)	$	262,439
Commercial paper ($9,759 included in cash equivalents)	40,386		—		(13)		40,373
U.S. government agency bonds	40,295		1		(111)		40,185
Money market fund investments (included in cash equivalents)	17,876		—		—		17,876
Corporate debt securities	11,489		50		(8)		11,531
Total cash equivalents and marketable securities	$	372,374	$	382	$	(352)	$	372,404

Classified as:
Cash and cash equivalents							$	51,162
Marketable securities, short-term							277,665
Marketable securities, long-term							43,577
Total cash equivalents and marketable securities							$	372,404


	As of December 31, 2022
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Commercial paper ($26,669 included in cash equivalents)	97,024		6		(131)		96,899
U.S. Treasury bills	92,910		1		(945)		91,966
U.S. government agency bonds (3,976 included in cash and cash equivalents)	63,926		25		(292)		63,659
Corporate debt securities	37,002		—		(183)		36,819
Money market fund investments (included in cash equivalents)	$	27,693	$	—	$	—	$	27,693
Total cash equivalents and marketable securities	$	318,555	$	32	$	(1,551)	$	317,036

Classified as:
Cash equivalents							$	58,338
Marketable securities, short-term							189,325
Marketable securities, long-term							69,373
Total cash equivalents and marketable securities							$	317,036

Contractual Maturity of Investments

The following table presents the fair value of available-for-sale marketable securities by contractual maturities (in thousands):


	December 31, 2023
Due in less than one year	$	277,665
Due in one to five years	43,577
Total	$	321,242

Schedule of Change in Fair Value of Financial Liability

The following table sets forth a summary of the changes in the fair value of our Level 3 financial liability (in thousands):


	MSKCC Success Payments Liability
Balance at December 31, 2021	$	4,080
Change in fair value	(2,429)
Balance at December 31, 2022	$	1,651
Change in fair value	1,288
Balance at December 31, 2023	$	2,939

Schedule of Assumptions Used in Valuation of MSKCC Success Payments Liability

The table below summarizes key assumptions used in the valuation of MSKCC success payments liability:


	As of December 31, 2023		As of December 31, 2022
Fair value of common stock	$	5.73	$	6.28
Risk-free interest rate	3.88%		3.88%
Expected volatility	79%		79%
Probability of achieving multiple of Initial Share Price(1)	5.2% to 18.1%		3.0% to 10.6%
Expected term (years)	3.7 to 5.2		4.6 to 6.0

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Follow-Up Public Offering, Net of Operating Expense	At-The-Market Offering, Net of Offering Expense	Private Placement	Common Stock	Common Stock Follow-Up Public Offering, Net of Operating Expense	Common Stock At-The-Market Offering, Net of Offering Expense	Common Stock Private Placement	Additional Paid-In Capital	Additional Paid-In Capital Follow-Up Public Offering, Net of Operating Expense	Additional Paid-In Capital At-The-Market Offering, Net of Offering Expense	Additional Paid-In Capital Private Placement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2021					60,263,158
Beginning balance at Dec. 31, 2021	$ 387,825				$ 6				$ 485,748				$ (135)	$ (97,794)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans (in shares)					69,113
Issuance of common stock under employee stock plans	$ 638								638
Issuance of common stock on exercise of stock options (in shares)	696,913				696,913
Issuance of common stock on exercise of options	$ 1,497								1,497
Stock-based compensation expense	11,715								11,715
Net loss	(99,421)													(99,421)
Other comprehensive income (loss)	(1,383)												(1,383)
Ending balance (in shares) at Dec. 31, 2022					61,029,184
Ending balance at Dec. 31, 2022	300,871				$ 6				499,598				(1,518)	(197,215)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock plans (in shares)					138,454
Issuance of common stock under employee stock plans	$ 787								787
Issuance of common stock on exercise of stock options (in shares)	228,264				228,264
Issuance of common stock on exercise of options	$ 793								793
Issuance of common stock on RSU release (in shares)					78,596
Issuance of common stock (in shares)						22,115,384	168,635	4,690,431
Issuance of common stock during different pursuits		$ 134,425	$ 1,007	$ 17,290		$ 2				$ 134,423	$ 1,007	$ 17,290
Stock-based compensation expense	13,750								13,750
Net loss	(102,070)													(102,070)
Other comprehensive income (loss)	1,548												1,548
Ending balance (in shares) at Dec. 31, 2023					88,448,948
Ending balance at Dec. 31, 2023	$ 368,401				$ 8				$ 667,648				$ 30	$ (299,285)

Significant Agreements

12 Months Ended

Dec. 31, 2023

Significant Agreements [Abstract]

Significant Agreements

The Regents of the University of California and the University of Vienna

We entered into an Exclusive License Agreement, dated April 16, 2013 (as amended, “UC/Vienna Agreement”) with The Regents of the University of California (“UC”) and the University of Vienna (“Vienna”) (together, “UC/Vienna”) wherein UC/Vienna granted us an exclusive worldwide license, with the right to sublicense, in all fields to the foundational

CRISPR-Cas9 patent family co-owned by UC, Vienna, and Dr. Emmanuelle Charpentier (“CVC IP”). Dr. Charpentier has not granted us any rights, either directly or indirectly. The UC/Vienna Agreement continues until the last-to-expire patent or last-to-be-abandoned patent application within the CVC IP; provided, however, that UC/Vienna may terminate the UC/Vienna Agreement upon the occurrence of certain events and we may terminate the UC/Vienna Agreement at our sole discretion upon written notice. Without patent term adjustment (“PTA”) or patent term extension (“PTE”), the CVC IP will expire in 2033. The UC/Vienna Agreement includes certain diligence milestones that we must meet. For products and services sold by us that are covered by the CVC IP, we will owe low- to mid-single-digit percent royalties on net sales, subject to a minimum annual royalty. Prior to the time that we are selling products, we owe UC/Vienna an annual license maintenance fee. We may owe UC/Vienna up to $3.4 million in certain regulatory and clinical milestone payments in the field of human therapeutics and diagnostics for products that are covered by the CVC IP and developed by us, an affiliate, or a sublicensee. Additionally, we pay UC/Vienna a specified percentage of sublicensing revenue, including cash and equity, we receive from sublicensing the CVC IP, subject to certain exceptions. If we include intellectual property owned or controlled by us in a sublicense to the CVC IP, we pay UC/Vienna a low double-digit percentage of sublicensing revenues received under the sublicense. If we do not include intellectual property owned or controlled by us in a sublicense to the CVC IP, we pay UC/Vienna 50% of sublicensing revenues received under the sublicense. To date, we have entered into over 25 sublicensing agreements in a variety of fields such as human therapeutics, forestry, agriculture, research reagents, transgenic animals, certain livestock targets, internal research, bioproduction, cell lines, and microbial applications that include the CVC IP as well as other Cas9 intellectual property owned or controlled by us. We are obligated to reimburse UC for its prosecution and maintenance costs of the CVC IP.

For the years ended December 31, 2023 and 2022, we incurred $1.6 million and $1.1 million, respectively, for payments we owe to UC related to sublicensing revenues, which we recorded in research and development expenses in our consolidated statements of operations and comprehensive loss.

For the years ended December 31, 2023 and 2022, we reimbursed UC $2.3 million and $5.4 million, respectively, for prosecution and maintenance costs of the CVC IP, which were recorded in general and administrative expenses in our consolidated statements of operations and comprehensive loss.

On December 15, 2016, we entered into a Consent to Assignments, Licensing and Common Ownership and Invention Management Agreement (“IMA”) relating to the CVC IP. Under the IMA, CRISPR Therapeutics AG (“CRISPR”) reimburses us 50% of the amounts we reimburse UC for patent prosecution and maintenance costs of the CVC IP. For the years ended December 31, 2023 and 2022, CRISPR reimbursed us $1.1 million and $2.7 million, respectively, which we recorded as reductions of general and administrative expenses in our consolidated statements of operations and comprehensive loss.

Memorial Sloan Kettering Cancer Center

On November 13, 2020, we entered into the MSKCC Agreement, under which we exclusively licensed know-how, biological materials, and patent families relating to fully-human single-chain variable fragments targeting C-type lectin-like molecule-1 (“CLL-1”; also known as CD371) for use in T cells, NK cells, and genome-edited induced pluripotent stem cells (“iPSCs”) for allogeneic CLL-1-targeted cell therapies (currently used in our CB-012 product candidate). We paid MSKCC an upfront payment of $0.5 million in cash and $2.1 million in stock. For each licensed CLL-1 product, we may owe potential clinical, regulatory, and commercial milestone payments totaling $112.0 million. In addition, in the event we, our affiliates, or sublicensees, receive regulatory approval for a licensed CLL-1 product, we will owe low- to mid-single-digit percent royalties on net sales by us, our affiliates, and our sublicensees. Our license from MSKCC includes the right to sublicense through multiple tiers and we will owe MSKCC a percentage of upfront cash or equity received from our sublicensees. The percentage owed decreases as our licensed CLL-1 product candidate moves through development, starting at a low-double-digit percentage if clinical trials have not yet begun and decreasing to a mid-single-digit percentage if our licensed CLL-1 product candidate is in later clinical trial stages. We are also responsible for paying a percentage of licensed patent costs. The MSKCC Agreement includes certain diligence milestones that we must meet by specified dates, which may be extended upon payment of additional fees.

MSKCC is entitled to certain success payments if our common stock fair value increases by certain multiples of increasing value based on a comparison of the fair market value of our common stock to $5.1914 per share, adjusted for any future stock splits (the “Initial Share Price”), during a specified time period. Under the MSKCC Agreement, as a publicly traded company, our common stock fair value is determined by any given 45-day volume weighted-average trading price. At our option, success payments to MSKCC may be made in cash or common stock. The relevant time period commences when the first patient is dosed with the first licensed CLL-1 product candidate (CB-012) in the first phase 1 clinical trial and ends upon the earlier of the third anniversary from the approval of our, or our affiliate’s, or sublicensee’s

biologics license application (“BLA”) by the FDA or 10 years from the date the first patient was dosed with a licensed CLL-1 product candidate in the first phase 1 clinical trial. The aggregate success payments will not exceed $35.0 million. Additionally, if we undergo a change of control during the specified time period, we may owe a change of control payment, depending upon the increase in our stock price due to the change of control and also to what extent success payments have already been paid by us to MSKCC. In no event will the combination of success payments and the change of control payment owed to MSKCC exceed $35.0 million.

The following table summarizes the amounts of the MSKCC success payments:


Multiple of Initial Share Price giving rise to a success payment	5		x	10		x	15		x
MSKCC success payments (in millions)	$	10.0		$	10.0		$	15.0

We may terminate the MSKCC Agreement upon 90 calendar days’ prior written notice to MSKCC. MSKCC may terminate the MSKCC Agreement in the event of our uncured material breach, bankruptcy, or criminal activity. If MSKCC materially breaches the MSKCC Agreement in certain circumstances (e.g., granting a third party a license in our field) then, during the time of such uncured breach, MSKCC will not be entitled to receive any success payments or any change of control payment.

As of December 31, 2023 and 2022, the estimated fair value of the total success payments obligation to MSKCC was $2.9 million and $1.7 million, respectively, which was included in long-term liabilities in our consolidated balance sheets.

Intellia Therapeutics, Inc.

On July 16, 2014, we entered into a License Agreement (as amended, “Intellia License Agreement”) with Intellia, LLC, to which Intellia Therapeutics, Inc. (“Intellia”) is a successor in interest. Under the Intellia License Agreement, we granted Intellia an exclusive worldwide license, with the right to sublicense, to certain CRISPR-Cas9 technology for a defined field of human therapeutics. Intellia granted us an exclusive worldwide license, with the right to sublicense, to certain of its CRISPR-Cas9 technology for all fields outside of the defined field of human therapeutics. Under the Intellia License Agreement, each party is responsible for 30% of the other party’s expenses for prosecution and maintenance of the licensed intellectual property.

During each of the years ended December 31, 2023 and 2022, we recognized less than $0.1 million of expenses in reimbursable patent prosecution and maintenance costs, which were recorded as general and administrative expenses in our consolidated statements of operations and comprehensive loss. During each of the years ended December 31, 2023 and 2022, Intellia reimbursed us $0.4 million and $0.8 million, respectively (including reimbursement for a portion of the patent prosecution and maintenance costs of the CVC IP paid to UC), which were recorded as reductions of general and administrative expenses in our consolidated statements of operations and comprehensive loss. The term of the Intellia License Agreement continues for the life of the licensed patents and patent applications; provided, however, either party may terminate the agreement upon the occurrence of certain events.

On June 16, 2021, we entered into a leaseback agreement with Intellia (“Leaseback Agreement”). Pursuant to the Leaseback Agreement, in exchange for Intellia’s grant to us of an exclusive license to certain intellectual property relating to CRISPR-Cas9, including Cas9 chRDNAs, for use solely in the manufacture of our CB-010 product candidate, we paid Intellia an upfront cash payment of $1.0 million and will pay up to $23.0 million in potential future regulatory and sales milestones. Additionally, we will owe Intellia low- to mid- single-digit percent royalties on net sales of our CB-010 product candidate by us, our affiliates, and sublicensees until the expiration, abandonment, or invalidation of the last patent within the intellectual property relating to CRISPR-Cas9, including that relating to Cas9 chRDNAs (i.e., 2036, without PTA or PTE).

Pioneer Hi-Bred International, Inc. (now Corteva Agriscience)

On July 13, 2015, we and Pioneer Hi-Bred International, Inc. (“Pioneer”) (now Corteva Agriscience), then a DuPont company (“DuPont”), entered into an Amended and Restated Collaboration and License Agreement (as amended, “Pioneer Agreement”). Under the terms of the Pioneer Agreement, we and Pioneer cross licensed CRISPR intellectual property portfolios. Pioneer granted us an exclusive worldwide license, with the right to sublicense, to its CRISPR intellectual property in the field of research tools, as well as a non-exclusive worldwide license to such intellectual property in human and animal therapeutics, industrial biotechnology, certain agriculture segments, and other fields; and we granted

Pioneer an exclusive worldwide license, with the right to sublicense, to our CRISPR intellectual property, including the CVC IP, in a defined field of agriculture relating to specified row crops, as well as a non-exclusive worldwide license to the intellectual property in other agricultural applications, industrial biotechnology, nutrition and health, and other fields. The Pioneer Agreement continues until the expiration, abandonment, or invalidation of the last patent or patent application within the licensed intellectual property; provided, however, that the parties may terminate the Pioneer Agreement by mutual consent or either party may unilaterally terminate the Pioneer Agreement in the event of an uncured breach of a payment obligation, bankruptcy, or failure to maintain or own licensed intellectual property by the other party if the non-breaching party is materially adversely affected by the failure. We are obligated to pay low-single-digit percent royalties to Pioneer for the sales of our products in the research tools field as well as certain sublicensing revenues in that field. We are eligible to receive milestone payments from Pioneer if certain regulatory and commercial milestones are met related to specified row crops, for a total of up to $22.4 million, as well as to receive low-single-digit percent royalties for sales of defined agricultural products and certain sublicensing revenues in that field. Initially, Pioneer owned the patents and patent applications developed under the collaboration, including the chRDNA patent family, and granted us an exclusive license to these patents and patent applications in the fields of research tools and therapeutics.

In December 2020, we and Pioneer entered into an amendment to the Pioneer Agreement under which Pioneer assigned to us the chRDNA patent family developed under the research collaboration, and we paid Pioneer an upfront payment of $0.5 million. We considered the payment to Pioneer in accordance with revenue recognition guidance and accounted for it as a reduction of the licensing and collaboration revenue in our consolidated statements of operations and comprehensive loss. In addition to the upfront payment, we are now obligated to pay all patent prosecution and maintenance costs for the chRDNA patent family; up to $2.8 million in regulatory milestone payments for therapeutic products developed by us, our affiliates, or licensees that are covered by the chRDNA patent family; up to $20.0 million in sales milestones over a total of four therapeutics products sold by us, our affiliates, or licensees that are covered by the chRDNA patent family; and a low-single-digit percentage of licensing revenue we receive for licensing the chRDNA patent family after December 2020.

During the year ended December 31, 2023 we incurred no liability for payments owed to Pioneer for licensing revenues. During the year ended December 31, 2022, we incurred $0.1 million, for payments we owe to Pioneer related to licensing revenues, which we recorded as a research and development expense in our consolidated statements of operations and comprehensive loss.

AbbVie Manufacturing Management Unlimited Company

On February 9, 2021, we entered into a Collaboration and License Agreement (as amended, “AbbVie Agreement”) with AbbVie Manufacturing Management Unlimited Company (“AbbVie”). Pursuant to the AbbVie Agreement, AbbVie selected one target or, for a dual CAR-T cell product, two targets (each selection, a “Program Slot”) to develop collaboration CAR-T cell products (and corresponding licensed products). Under the terms of the AbbVie Agreement, we conducted certain preclinical research and development activities under the collaboration. AbbVie reimbursed us for all such activities, including reimbursement for time spent by employees at a designated rate. On September 26, 2023, we received notice from AbbVie that AbbVie elected to terminate the AbbVie Agreement. By mutual agreement with AbbVie, termination of the AbbVie Agreement became effective on October 25, 2023.

The transaction price we received under the AbbVie Agreement associated with the first two Program Slots consisted of a $30.0 million upfront, non-refundable and non-creditable, cash payment and the estimated variable consideration related to our performance of preclinical research, development, and manufacturing activities under the collaboration and the developmental and regulatory milestone payments. We constrain the estimated variable consideration if we assess that it is probable that a significant reversal in the amount of cumulative revenue recognized may occur in future periods. The transaction price was reevaluated at the end of each reporting period and as changes in circumstances occurred. We determined that the licenses we granted to AbbVie and our participation in the joint governance committee were not capable of being distinct from the preclinical research, development, and manufacturing activities and therefore were combined into one performance obligation. We recognized revenue based on the measure of progress using an estimated cost-based input method each reporting period.

Upon to receipt of the termination notice, we stopped performing preclinical research and development services under the AbbVie Agreement and determined that our performance obligation to AbbVie was substantially completed as of September 30, 2023. Consequently, the remaining $20.8 million of deferred revenue from the $30.0 million upfront cash payment was recognized upon satisfaction of the performance obligation during the year ended December 31 2023.

We had no long-term or short-term deferred revenue related to the upfront cash payment in our consolidated balance sheets as of December 31, 2023. We had short-term deferred revenue of $9.4 million and long-term deferred revenue of $13.3 million related to the upfront cash payment in our consolidated balance sheets as of December 31, 2022.

During the year ended December 31, 2023, we recognized $24.8 million in licensing and collaboration revenue associated with the AbbVie Agreement, of which $22.7 million had been included in deferred revenue as of the beginning of the period. During the year ended December 31, 2022, we recognized $8.0 million in licensing and collaboration revenue associated with the AbbVie Agreement. As of December 31, 2023 and 2022, we had no amounts recorded in accounts receivable in our consolidated balance sheets. As of December 31, 2023, we had no contract assets in our consolidated balance sheets. As of December 31, 2022, we had $0.9 million in contract assets in our consolidated balance sheets.

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary Of Provision For Credit Losses and other Uncertainties

Licensees that represent 10% or more of our revenue and accounts receivable and contract assets were as follows:


	Revenue				Accounts Receivable and Contract Assets
	Years Ended December 31,				As of December 31,
	2023		2022		2023		2022
Licensee A	*		16.2	%	47.5	%	23.8	%
Licensee B	71.9	%	57.4	%	*		36.6	%
Total	71.9	%	73.6	%	47.5	%	60.4	%

*Less than 10%

Schedule of Property and Equipment


Computer equipment			3 years
Furniture and office equipment			5 years
Lab equipment			5 years
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Property and equipment, net, consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Lab equipment	$	15,581	$	12,588
Leasehold improvements	2,235		1,876
Computer equipment	895		709
Furniture and office equipment	499		161
Construction in progress	8,204		993
Total property and equipment	27,414		16,327
Less accumulated depreciation and amortization	(9,144)		(5,649)
Property and equipment, net	$	18,270	$	10,678

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Pre-tax book income (loss) in the United States	$ (101,900,000)	$ (99,400,000)
Deferred tax assets, valuation allowance	96,166,000	66,408,000	$ 34,521,000
Capitalized research and development expense	102,600,000	93,900,000
Unrecognized tax benefits that would impact effective tax rate	0
Unrecognized tax benefits, income tax penalties and interest accrued	$ 0	$ 0
Operating Loss Carryforward Indefinitely Member
Income Taxes [Line Items]
Net operating loss carryforwards stock ownership percentage	5.00%
Federal
Income Taxes [Line Items]
Federal net operating loss carryforwards	$ 103,800,000
Deferred tax assets, tax credit carryforwards, research	$ 14,200,000
Amortization period (in years)	5 years
State
Income Taxes [Line Items]
State net operating loss carryforwards	$ 172,700,000
Deferred tax assets, tax credit carryforwards, research	$ 5,600,000
Foreign Tax Authority
Income Taxes [Line Items]
Amortization period (in years)	15 years

Stock-Based Compensation - Additional Information (Details) - USD ($)		1 Months Ended	12 Months Ended		29 Months Ended
	Jul. 22, 2021	Jul. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)			17,084,128	13,867,717	17,084,128
Common stock outstanding percentage	5.00%
Stock option expiration period			5 years
Stock options granted during period (in shares)			3,524,616	1,409,475
Unrecognized stock based-compensation expense			$ 25,800,000		$ 25,800,000
Weighted-average period			2 years 6 months
Accrued liabilities			$ 500,000	$ 300,000	$ 500,000
Non-Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cash based compensation		$ 1,000,000
Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted during period (in shares)			3,524,616	1,409,475
Weighted average grant date fair value (in dollars per share)			$ 3.88	$ 5.82
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of price of shares granted at fair value	110.00%
Cash based compensation		$ 750,000
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	5,200,000		5,952,012		5,952,012
Stock option expiration period	10 years
2013 Stock Option Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for issuance (in shares)	934,562
Employee Stock Purchase Plan 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		511,000
Percentage of price of shares granted at fair value		85.00%
Capital shares reserved for future issuance, yearly percentage increase (as a percent)		1.00%
Common stock shares issued (in shares)		10,000,000			207,567
Percentage of eligible employee to purchase shares of common stock discount		15.00%
Incentive Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of price of shares granted at fair value	10.00%
Incentive Stock Options \| 2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum shares of stock issued (in shares)	56,000,000
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period			1 year
Granted (in shares)			75,000
Unrecognized stock-based compensation expense, excluding options			$ 800,000		$ 800,000
Performance Restricted Stock Units (PRSU)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted (in shares)			0
Unrecognized stock-based compensation expense, excluding options			$ 600,000		$ 600,000

Significant Agreements - Summary Of MSKCC Success Payments Amounts (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
5x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
MSKCC Success payments (in millions)	$ 10.0
10x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
MSKCC Success payments (in millions)	10.0
15x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
MSKCC Success payments (in millions)	$ 15.0

Significant Agreements (Tables)

12 Months Ended

Dec. 31, 2023

Significant Agreements [Abstract]

Summary of Amounts of Success Payments MSKCC

The following table summarizes the amounts of the MSKCC success payments:


Multiple of Initial Share Price giving rise to a success payment	5		x	10		x	15		x
MSKCC success payments (in millions)	$	10.0		$	10.0		$	15.0

401(k) Savings Plan	12 Months Ended
401(k) Savings Plan	Dec. 31, 2023
Retirement Benefits [Abstract]
401(k) Savings plan	401(k) Savings Plan In 2017, we established a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code of 1986, as amended (“Tax Code”). Our 401(k) plan is available to all employees and allows participants to defer a portion of their annual compensation on a pretax basis subject to applicable laws. We also provide a 4% match for employee contributions up to a certain limit. During the years ended December 31, 2023 and 2022, we contributed $1.1 million and $0.7 million, respectively, to our 401(k) plan.

Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenue	$ 34,477	$ 13,851
United States
Disaggregation Of Revenue [Line Items]
Revenue	32,770	13,303
Rest of world
Disaggregation Of Revenue [Line Items]
Revenue	$ 1,707	$ 548

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

- Definition

+ References

+ Details

Revenue - Schedule of Changes in Company's Contract Assets and Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Accounts receivable
Accounts receivable, Beginning balance	$ 202
Accounts receivable, Additions	10,819
Accounts receivable, Deductions	(10,873)
Accounts receivable, Ending balance	148
Contract assets:
Unbilled accounts receivable, Beginning balance	2,247
Unbilled accounts receivable, Additions	6,006
Unbilled accounts receivable, Deductions	(6,828)
Unbilled accounts receivable, Ending balance	1,425
Contract liabilities:
Deferred revenue, current and long-term, Beginning balance	25,891
Deferred revenue, current and long-term, Additions	12,981
Deferred revenue, current and long-term, Deductions	(29,923)
Deferred revenue, current and long-term, Ending balance	$ 8,949

Revenue (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

The following table is a summary of revenue by geographic location for the years ended December 31, 2023 and 2022, (in thousands):


	Years Ended December 31,
	2023		2022
United States	$	32,770	$	13,303
Rest of world	1,707		548
Total	$	34,477	$	13,851

Schedule of Changes in Company's Contract Assets and Liabilities

The following table presents changes in our contract assets and liabilities during the year ended December 31, 2023 (in thousands):


	Balance as of December 31, 2022		Additions		Deductions		Balance as of December 31, 2023
Accounts receivable	$	202	$	10,819	$	(10,873)	$	148

Contract assets:
Unbilled accounts receivable	$	2,247	$	6,006	$	(6,828)	$	1,425

Contract liabilities:
Deferred revenue, current and long-term	$	25,891	$	12,981	$	(29,923)	$	8,949

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Financial Instruments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Liabilities:
Cash and cash equivalents	$ 51,162	$ 58,338
US Government Agency Bonds
Liabilities:
Cash and cash equivalents		3,976
Fair Value, Recurring
Assets:
Assets fair value	372,404	317,036
Liabilities:
Liabilities fair value	2,939	1,651
Fair Value, Recurring \| U.S. Treasury bills
Liabilities:
Cash and cash equivalents	23,527
Fair Value, Recurring \| Commercial Paper
Liabilities:
Cash and cash equivalents	9,759	26,669
Fair Value, Recurring \| US Government Agency Bonds
Liabilities:
Cash and cash equivalents		3,976
Fair Value, Recurring \| U.S. Treasury bills
Assets:
Assets fair value	262,439	91,966
Fair Value, Recurring \| Commercial Paper
Assets:
Assets fair value	40,373	96,899
Fair Value, Recurring \| US Government Agency Bonds
Assets:
Assets fair value	40,185	63,659
Fair Value, Recurring \| Money Market Funds
Assets:
Assets fair value	17,876	27,693
Fair Value, Recurring \| Corporate debt securities
Assets:
Assets fair value	11,531	36,819
Fair Value, Recurring \| MSKCC success payments liability
Liabilities:
Liabilities fair value	2,939	1,651
Fair Value, Recurring \| Level 1
Assets:
Assets fair value	280,315	119,659
Liabilities:
Liabilities fair value	0	0
Fair Value, Recurring \| Level 1 \| U.S. Treasury bills
Assets:
Assets fair value	262,439	91,966
Fair Value, Recurring \| Level 1 \| Commercial Paper
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 1 \| US Government Agency Bonds
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 1 \| Money Market Funds
Assets:
Assets fair value	17,876	27,693
Fair Value, Recurring \| Level 1 \| Corporate debt securities
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 1 \| MSKCC success payments liability
Liabilities:
Liabilities fair value	0	0
Fair Value, Recurring \| Level 2
Assets:
Assets fair value	92,089	197,377
Liabilities:
Liabilities fair value	0	0
Fair Value, Recurring \| Level 2 \| U.S. Treasury bills
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 2 \| Commercial Paper
Assets:
Assets fair value	40,373	96,899
Fair Value, Recurring \| Level 2 \| US Government Agency Bonds
Assets:
Assets fair value	40,185	63,659
Fair Value, Recurring \| Level 2 \| Money Market Funds
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 2 \| Corporate debt securities
Assets:
Assets fair value	11,531	36,819
Fair Value, Recurring \| Level 2 \| MSKCC success payments liability
Liabilities:
Liabilities fair value	0	0
Fair Value, Recurring \| Level 3
Assets:
Assets fair value	0	0
Liabilities:
Liabilities fair value	2,939	1,651
Fair Value, Recurring \| Level 3 \| U.S. Treasury bills
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 3 \| Commercial Paper
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 3 \| US Government Agency Bonds
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 3 \| Money Market Funds
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 3 \| Corporate debt securities
Assets:
Assets fair value	0	0
Fair Value, Recurring \| Level 3 \| MSKCC success payments liability
Liabilities:
Liabilities fair value	$ 2,939	$ 1,651

Balance Sheet Items (Tables)

12 Months Ended

Dec. 31, 2023

Balance Sheet Related Disclosures [Abstract]

Schedule of Other Receivables

Other receivables consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Patent cost reimbursements	$	1,403	$	1,638
Accrued interest on marketable securities	702		570
Other	181		7
Total	$	2,286	$	2,215

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Prepaid contract manufacturing and clinical costs	$	3,942	$	4,803
Prepaid income taxes	—		431
Prepaid insurance	993		1,568
Other	1,220		1,119
Total	$	6,155	$	7,921

Schedule of Property and Equipment


Computer equipment			3 years
Furniture and office equipment			5 years
Lab equipment			5 years
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Property and equipment, net, consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Lab equipment	$	15,581	$	12,588
Leasehold improvements	2,235		1,876
Computer equipment	895		709
Furniture and office equipment	499		161
Construction in progress	8,204		993
Total property and equipment	27,414		16,327
Less accumulated depreciation and amortization	(9,144)		(5,649)
Property and equipment, net	$	18,270	$	10,678

Summary of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Accrued employee compensation and related expenses	9,517		5,752
Accrued research and development expenses	8,720		6,731
Accrued patent expenses	613		1,331
Accrued expenses related to sublicensing revenues	802		596
Credit card liability	377		299
Other	1,106		1,370
Total	$	21,135	$	16,079

Revenue - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 29, 2023	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenue		$ 34,477	$ 13,851
Revenue recognized included in the opening contract liabilities balance		23,200	5,000
Contract with customer liability increase for new contract	$ 7,500
Remaining performance obligations		8,900	40,400
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligations		$ 2,800
Remaining performance obligation, expected timing of satisfaction, period		12 months
Collaboration and License Agreement with AbbVie
Disaggregation Of Revenue [Line Items]
Revenue		$ 24,800	8,000
Revenue recognized included in the opening contract liabilities balance		22,700
Point in Time
Disaggregation Of Revenue [Line Items]
Revenue		8,400	5,900
Over Time
Disaggregation Of Revenue [Line Items]
Revenue		$ 26,100	$ 8,000

Summary of Significant Accounting Policies - Summary of Property, Plant, and Equipment Useful Life (Details)	Dec. 31, 2023
Computer equipment
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years

Stock-Based Compensation - Schedule of Estimated Fair Value of Stock Options on the Grant Date Using Black-Scholes Option-Pricing Model (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	74.10%	71.70%
Expected term (in years)	5 years	5 years 6 months
Risk-free interest rate	3.50%	1.70%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	75.80%	74.20%
Expected term (in years)	6 years	6 years
Risk-free interest rate	4.90%	4.40%

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Income Taxes - Schedule of Deferred Tax Valuation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Valuation [Roll Forward]
Deferred valuation allowance, beginning balance	$ 66,408	$ 34,521
Change charged to expense	29,758	31,887
Deferred valuation allowance, ending balance	$ 96,166	$ 66,408