Caribou Biosciences (CRBU) 10-Q 8 Aug 23 2023 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Aug. 03, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
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 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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		88,284,776
Entity Central Index Key	0001619856
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q2
Amendment Flag	false
Document Fiscal Year Focus	2023

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
CURRENT ASSETS
Cash and cash equivalents	$ 66,194	$ 58,338
Marketable securities, short-term	193,038	189,325
Accounts receivable	766	202
Contract assets	1,481	2,247
Other receivables	1,495	2,215
Prepaid expenses and other current assets	5,564	7,921
Total current assets	268,538	260,248
NON-CURRENT ASSETS
Investments in equity securities	7,766	7,698
Marketable securities, long-term	33,289	69,373
Property and equipment, net	15,429	10,678
Operating lease, right of use assets	23,206	24,230
Other assets	1,419	1,538
TOTAL ASSETS	349,647	373,765
CURRENT LIABILITIES
Accounts payable	4,433	1,146
Accrued expenses and other current liabilities	15,901	16,079
Lease liabilities, current	1,079	966
Deferred revenue ($2,487 and $150 from related party, respectively)	12,962	9,937
Total current liabilities	34,375	28,128
LONG-TERM LIABILITIES
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	18,162	15,954
MSKCC success payments liability	1,117	1,651
Lease liabilities, non-current	26,155	26,780
Deferred tax liabilities	380	381
Total liabilities	80,189	72,894
COMMITMENTS AND CONTINGENCIES (Note 9)
STOCKHOLDERS’ EQUITY
Preferred stock, par value $0.0001 per share, 10,000,000 shares authorized at June 30, 2023 and December 31, 2022; no shares issued and outstanding as of June 30, 2023 and December 31, 2022	0	0
Common stock, value, issued	6	6
Additional paid-in-capital	525,366	499,598
Accumulated other comprehensive loss	(1,136)	(1,518)
Accumulated deficit	(254,778)	(197,215)
Total stockholders’ equity	269,458	300,871
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 349,647	$ 373,765

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Deferred revenue ($2,487 and $150 from related party, respectively)	$ 12,962	$ 9,937
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	$ 18,162	$ 15,954
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, shares issued (in shares)	0	0
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 outstanding (in shares)	66,100,039	61,029,184
Common stock, shares issued (in shares)	66,100,039	61,029,184
Related Party
Deferred revenue ($2,487 and $150 from related party, respectively)	$ 2,487	$ 150
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	$ 4,973	$ 0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Licensing and collaboration revenue (including $1,150 for three and six months ended June 2023 from related party, and none for all other periods)	$ 3,755	$ 4,192	$ 7,257	$ 6,856
Operating expenses:
Research and development	26,503	22,579	52,212	36,503
General and administrative	10,120	10,044	19,029	19,637
Total operating expenses	36,623	32,623	71,241	56,140
Loss from operations	(32,868)	(28,431)	(63,984)	(49,284)
Other income (expense):
Change in fair value of equity securities	22	(16)	7	(104)
Change in fair value of MSKCC success payments liability	279	1,052	534	2,648
Other income, net	3,048	698	5,880	955
Total other income	3,349	1,734	6,421	3,499
Net loss	(29,519)	(26,697)	(57,563)	(45,785)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale marketable securities, net of tax	(406)	(492)	382	(1,446)
Net comprehensive loss	$ (29,925)	$ (27,189)	$ (57,181)	$ (47,231)
Net loss per share, basic (in dollars per share)	$ (0.48)	$ (0.44)	$ (0.94)	$ (0.75)
Net loss per share, diluted (in dollars per share)	$ (0.48)	$ (0.44)	$ (0.94)	$ (0.75)
Weighted-average common shares outstanding, basic (in shares)	61,417,934	60,757,689	61,302,863	60,652,532
Weighted-average common shares outstanding, diluted (in shares)	61,417,934	60,757,689	61,302,863	60,652,532

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive 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)		36,596
Issuance of common stock under employee stock plans	361		361
Issuance of common stock on exercise of stock options (in shares)		389,855
Issuance of common stock on exercise of options	629		629
Stock-based compensation expense	3,024		3,024
Net loss	(19,088)				(19,088)
Other comprehensive income	(954)			(954)	0
Ending balance (in shares) at Mar. 31, 2022		60,689,609
Ending balance at Mar. 31, 2022	371,797	$ 6	489,762	(1,089)	(116,882)
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]
Net loss	(45,785)
Ending balance (in shares) at Jun. 30, 2022		60,838,370
Ending balance at Jun. 30, 2022	347,889	$ 6	493,043	(1,581)	(143,579)
Beginning balance (in shares) at Mar. 31, 2022		60,689,609
Beginning balance at Mar. 31, 2022	371,797	$ 6	489,762	(1,089)	(116,882)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock on exercise of stock options (in shares)		148,761
Issuance of common stock on exercise of options	363		363
Stock-based compensation expense	2,918		2,918
Net loss	(26,697)				(26,697)
Other comprehensive income	(492)			(492)
Ending balance (in shares) at Jun. 30, 2022		60,838,370
Ending balance at Jun. 30, 2022	347,889	$ 6	493,043	(1,581)	(143,579)
Beginning balance (in shares) at Dec. 31, 2022		61,029,184
Beginning 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)		70,271
Issuance of common stock under employee stock plans	404		404
Issuance of common stock on exercise of stock options (in shares)		55,433
Issuance of common stock on exercise of options	115		115
Issuance of common stock (in shares)		168,635
Issuance of common stock	1,007		1,007
Stock-based compensation expense	3,131		3,131
Net loss	(28,044)				(28,044)
Other comprehensive income	788			788
Ending balance (in shares) at Mar. 31, 2023		61,323,523
Ending balance at Mar. 31, 2023	278,272	$ 6	504,255	(730)	(225,259)
Beginning balance (in shares) at Dec. 31, 2022		61,029,184
Beginning 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 on exercise of stock options (in shares)	126,518
Net loss	$ (57,563)
Ending balance (in shares) at Jun. 30, 2023		66,100,039
Ending balance at Jun. 30, 2023	269,458	$ 6	525,366	(1,136)	(254,778)
Beginning balance (in shares) at Mar. 31, 2023		61,323,523
Beginning balance at Mar. 31, 2023	278,272	$ 6	504,255	(730)	(225,259)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock on exercise of stock options (in shares)		86,085
Issuance of common stock on exercise of options	236		236
Issuance of common stock (in shares)		4,690,431
Issuance of common stock	17,290		17,290
Stock-based compensation expense	3,585		3,585
Net loss	(29,519)				(29,519)
Other comprehensive income	(406)			(406)
Ending balance (in shares) at Jun. 30, 2023		66,100,039
Ending balance at Jun. 30, 2023	$ 269,458	$ 6	$ 525,366	$ (1,136)	$ (254,778)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (57,563)	$ (45,785)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,206	666
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	(7)	104
Stock-based compensation expense	6,716	5,942
Change in fair value of MSKCC success payments liability	(534)	(2,648)
Acquired in-process research and development	0	300
(Accretion of discounts) and amortization of premiums on investments, net	(3,598)	449
Non-cash lease expense	1,024	1,000
Changes in operating assets and liabilities:
Accounts receivable	(564)	629
Contract assets	765	(606)
Other receivables	720	2,388
Prepaid expenses and other current assets	2,356	(347)
Other assets	119	(326)
Accounts payable	2,042	(3,557)
Accrued expenses and other current liabilities	(431)	1,117
Deferred revenue, current and long-term	5,231	(2,470)
Operating lease liabilities	(511)	(182)
Other liabilities	0	(15)
Net cash used in operating activities	(43,124)	(43,546)
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales and maturities of marketable securities	171,025	99,009
Purchases of marketable securities	(134,674)	(181,746)
Purchases of property and equipment	(4,584)	(3,343)
Net cash provided by (used in) investing activities	31,767	(86,080)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock in a private placement with Pfizer	17,450	0
Proceeds from exercise of stock options and purchases of common stock under employee stock purchase plan	755	1,352
Proceeds from issuance of common stock related to at-the-market offering, net of offering expenses	1,008	0
Net cash provided by financing activities	19,213	1,352
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	7,856	(128,274)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — BEGINNING OF PERIOD	58,384	240,466
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH — END OF PERIOD	66,240	112,192
RECONCILIATION OF CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Cash and cash equivalents	66,194	112,146
Restricted cash	46	46
TOTAL CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	66,240	112,192
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	2,562	707
Acquired in-process research and development accrued	0	300
Offering costs included in accrued expenses	160	0
Right-of-use-assets obtained in exchange for new operating lease liabilities	$ 0	$ 26,249

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Licensing and collaboration revenue (including $1,150 for three and six months ended June 2023 from related party, and none for all other periods)	$ 3,755,000	$ 4,192,000	$ 7,257,000	$ 6,856,000
Related Party
Licensing and collaboration revenue (including $1,150 for three and six months ended June 2023 from related party, and none for all other periods)	$ 1,150,000	$ 0	$ 1,150,000	$ 0

Description of the Business, Or

Description of the Business, Organization, and Liquidity	6 Months Ended
	Jun. 30, 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. (the “Company” or “we”) is a clinical-stage C lustered R egularly I nterspaced S hort P alindromic R epeats (“CRISPR”) genome-editing biopharmaceutical company dedicated to developing transformative therapies for patients with devastating diseases. Our genome-editing platform, including our novel chRDNA ( C RISPR h ybrid R NA- DNA , or “chRDNA,” pronounced “chardonnay”) technologies, enables superior editing precision 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 net losses and negative cash flows from operations since our inception and we had an accumulated deficit of $254.8 million as of June 30, 2023. During the six months ended June 30, 2023, we incurred a net loss of $57.6 million and used $43.1 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, approval, and commercialization of our product candidates and on our achievement 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 $292.5 million as of June 30, 2023, will be sufficient to fund our current operating plan for at least the next 12 months from the date of issuance of our condensed consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies There have been no changes to the significant accounting policies disclosed in Note 2 to the annual consolidated financial statements for the year ended December 31, 2022, included in our Annual Report on Form 10-K (“Form 10-K”). Basis of Presentation and Principles of Consolidation The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and include the accounts of Caribou Biosciences, Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions are eliminated in consolidation. Use of Estimates The preparation of condensed 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 condensed 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, common stock valuation, stock-based compensation expense, accrued expenses related to research and development activities, valuation of the Memorial Sloan Kettering Cancer Center (“MSKCC”) success payments liability, 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. 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 two financial institutions, and 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 Revenue Accounts Receivable and Contract Assets Three Months Ended Six Months Ended As of As of June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Licensee A 17.1 % 13.8 % 19.5 % 16.1 % 28.4 % 23.8 % Licensee B 36.6 % 68.3 % 41.1 % 55.4 % 45.6 % 36.6 % Licensee C 30.6 % * 15.8 % * * * Total 84.3 % 82.1 % 76.4 % 71.5 % 74.0 % 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 June 30, 2023, or December 31, 2022. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“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, and interim reporting periods within fiscal years beginning after December 15, 2023. 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 on our financial statements and related disclosures was not material.

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements and Fair Value of Financial Instruments	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 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 evaluation 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 six months ended June 30, 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 June 30, 2023 Total Level 1 Level 2 Level 3 Assets: U.S. Treasury bills ($18,295 included in cash and cash equivalents) $ 159,788 $ 159,788 $ — $ — U.S. government agency bonds 57,010 — 57,010 — Money market fund investments (included in cash and cash equivalents) 47,899 47,899 — — Commercial paper 15,655 — 15,655 — Corporate debt securities 12,169 — 12,169 — Total fair value of assets $ 292,521 $ 207,687 $ 84,834 $ — Liabilities: MSKCC success payments liability $ 1,117 $ — $ — $ 1,117 Total fair value of liabilities $ 1,117 $ — $ — $ 1,117 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 June 30, 2023, and December 31, 2022 are presented in the following tables (in thousands): As of June 30, 2023 Amortized Cost Basis Unrealized Gains Unrealized Losses Estimated Fair Value U.S. Treasury bills ($18,295 included in cash and cash equivalents) $ 160,455 $ 16 $ (683) $ 159,788 U.S. government agency bonds 57,442 — (432) 57,010 Money market investments (included in cash equivalents) 47,899 — — 47,899 Commercial paper 15,674 — (19) 15,655 Corporate debt securities 12,187 4 (22) 12,169 Total cash equivalents and marketable securities $ 293,657 $ 20 $ (1,156) $ 292,521 Classified as: Cash and cash equivalents $ 66,194 Marketable securities, short-term 193,038 Marketable securities, long-term 33,289 Total cash equivalents and marketable securities $ 292,521 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 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 and cash equivalents $ 58,338 Marketable securities, short-term 189,325 Marketable securities, long-term 69,373 Total cash equivalents and marketable securities $ 317,036 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 Balance at December 31, 2022 $ 1,651 Change in fair value (534) Balance at June 30, 2023 $ 1,117 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. We recorded a $0.3 million and $1.1 million change in the fair value of the MSKCC success payments liability as a gain in other income (expense) in our condensed consolidated statements of operations and comprehensive loss for the three months ended June 30, 2023, and 2022, respectively. We recorded $0.5 million and $2.6 million change in fair value of the MSKCC success payments liability as a gain in other income (expense) in our condensed consolidated statements of operations and comprehensive loss for the six months ended June 30, 2023, and 2022, respectively. As of December 31, 2022, we utilized a Monte Carlo simulation model 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 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. The table below summarizes key assumptions used in the valuation of MSKCC success payments liability: As of Fair value of common stock $ 6.28 Risk-free interest rate 3.88% Expected volatility 79% Probability of achieving multiple of Initial Share Price (1) 3.0% to 10.6% Expected term (years) 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 (the “Initial Share Price”), during a specified time period. For further information regarding our agreement with MSKCC, see Note 4 to the consolidated financial statements included in our Form 10-K. 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 estimated timing of our 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 (the “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. As of June 30, 2023, we did not note any significant changes to the inputs used in the MSKCC success payments liability fair value calculation, other than a change in the fair value of our common stock to $4.25 per share.

Significant Agreements

Significant Agreements	6 Months Ended
	Jun. 30, 2023
Significant Agreements [Abstract]
Significant Agreements	Significant Agreements Since December 31, 2022, there have been no material changes to the key terms of our significant agreements other than the addition of the Pfizer Inc. (“Pfizer”) investment agreements. See Note 15 to our unaudited condensed consolidated financial statements included elsewhere in this Form 10-Q for additional information on the Pfizer agreements. For further information regarding our significant agreements, see Note 4 to the consolidated financial statements included in our Form 10-K. On February 9, 2021, we entered into a Collaboration and License Agreement (as amended, the “AbbVie Agreement”) with AbbVie Manufacturing Management Unlimited Company (“AbbVie”). We received an upfront cash payment of $30.0 million from AbbVie during the year ended December 31, 2021. We recognized short-term deferred revenue in the amount of $10.0 million and long-term deferred revenue in the amount of $10.8 million related to this upfront cash payment in our condensed consolidated balance sheets as of June 30, 2023. We recognized short-term deferred revenue in the amount of $9.4 million and long-term deferred revenue in the amount of $13.3 million related to this upfront cash payment in our consolidated balance sheets as of December 31, 2022. We recognized $1.4 million and $2.9 million in revenue for the three months ended June 30, 2023, and 2022, respectively, relating to the AbbVie Agreement. We recognized $3.0 million and $3.8 million in revenue for the six months ended June 30, 2023, and 2022, respectively, relating to the AbbVie Agreement. As of June 30, 2023, we recorded $0.6 million in accounts receivable and as of December 31, 2022, we had recorded no amounts in accounts receivable in our condensed consolidated balance sheets. As of June 30, 2023, and December 31, 2022, we had $0.5 million and $0.9 million, respectively, in contract assets in our condensed consolidated balance sheets. We enter into agreements with third parties to in-license intellectual property and related materials and know-how. These agreements may include non-refundable, upfront payments; annual license maintenance fees; sublicensing fees; obligations to reimburse for patent prosecution and maintenance fees; success payments; regulatory clinical and commercial milestones; and royalty payments. Our obligation to make such payments is contingent upon milestones being achieved, licensed products being commercialized, and the agreements remaining in effect. For the three months ended June 30, 2023, and 2022, we recorded $0.4 million and $0.2 million, respectively, as research and development expense in our condensed consolidated statements of operations related to our license agreements. For the six months ended June 30, 2023, and 2022, we recorded $0.8 million and $0.5 million, respectively, as research and development expense in our condensed consolidated statements of operations related to our license agreements. For the three months ended June 30, 2023, and 2022, we recorded $1.0 million and $1.2 million, respectively, as general and administrative expense for patent prosecution and maintenance costs in our condensed consolidated statements of operations and comprehensive loss, which includes reimbursements of patent prosecution and maintenance costs of $0.7 million and $0.7 million, respectively, from CRISPR Therapeutics AG and Intellia Therapeutics, Inc. For the six months ended June 30, 2023, and 2022, we recorded $1.8 million and $3.7 million, respectively, as general and administrative expense for patent prosecution and maintenance costs in our condensed consolidated statements of operations and comprehensive loss, which includes reimbursements of patent prosecution and maintenance costs of $1.1 million and $2.1 million, respectively, from CRISPR Therapeutics AG and Intellia Therapeutics, Inc. As of June 30, 2023, certain license and assignment agreements included potential future payments from us for development, regulatory, and sales milestones totaling approximately $161.2 million.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue	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 three and six months ended June 30, 2023, and 2022 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 United States $ 3,746 $ 4,183 $ 7,131 $ 6,795 Rest of world 9 9 126 61 Total $ 3,755 $ 4,192 $ 7,257 $ 6,856 During the three months ended June 30, 2023, we recognized $2.4 million of revenue related to performance obligations satisfied at a point in time, and we recognized $1.4 million of revenue related to performance obligations satisfied over time. During the three months ended June 30, 2022, we recognized $1.3 million of revenue related to performance obligations satisfied at a point in time, and we recognized $2.9 million of revenue related to performance obligations satisfied over time. During the six months ended June 30, 2023, we recognized $4.3 million of revenue related to performance obligations satisfied at a point in time, and we recognized $3.0 million of revenue related to performance obligations satisfied over time. During the six months ended June 30, 2022, we recognized $3.1 million of revenue related to performance obligations satisfied at a point in time, and we recognized $3.8 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 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. Our deferred revenue primarily results from the upfront payment received relating to the performance obligation that is satisfied over time under the AbbVie Agreement. The remaining deferred revenue relates to upfront payments received under license agreements that also include non-refundable 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 six months ended June 30, 2023 (in thousands): Balance as of Additions Deductions Balance as of Accounts receivable $ 202 $ 5,704 $ (5,140) $ 766 Contract assets: Unbilled accounts receivable $ 2,247 $ 3,023 $ (3,789) $ 1,481 Contract liabilities: Deferred revenue, current and long-term $ 25,891 $ 10,326 $ (5,095) $ 31,122 Unbilled accounts receivable decreased $0.8 million during the six months ended June 30, 2023, primarily due to the decrease in unbilled research costs under the AbbVie Agreement. Deferred revenue increased during the six months ended June 30, 2023, primarily due to the $7.5 million allocated to the Pfizer information sharing committee during the six months ended June 30, 2023. See Note 15 to our unaudited condensed consolidated financial statements included elsewhere in this Form 10-Q for additional information. During the six months ended June 30, 2023, and 2022, we recognized $2.4 million and $2.5 million of revenue, respectively, which were 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 June 30, 2023, was approximately $43.9 million. We expect to recognize approximately $13.0 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.

Balance Sheet Items

Balance Sheet Items	6 Months Ended
	Jun. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Items	Balance Sheet Items Other receivables consisted of the following (in thousands): June 30, December 31, Patent cost reimbursements $ 1,194 $ 1,638 Accrued interest on marketable securities 275 570 Other 26 7 Total $ 1,495 $ 2,215 Prepaid expenses and other current assets consisted of the following (in thousands): June 30, December 31, Prepaid contract manufacturing and clinical costs $ 3,228 $ 4,803 Prepaid insurance 248 1,568 Prepaid income taxes 603 431 Other 1,485 1,119 Total $ 5,564 $ 7,921 Property and equipment, net, consisted of the following (in thousands): June 30, December 31, Lab equipment $ 14,177 $ 12,588 Leasehold improvements 1,993 1,876 Computer equipment 809 709 Furniture and equipment 161 161 Construction in progress 5,115 993 Total property and equipment, gross 22,255 16,327 Less: accumulated depreciation and amortization (6,826) (5,649) Property and equipment, net $ 15,429 $ 10,678 Depreciation and amortization expenses related to property and equipment were $0.6 million and $0.4 million, respectively, for the three months ended June 30, 2023, and 2022. Depreciation and amortization expenses related to property and equipment were $1.2 million and $0.7 million, respectively, for the six months ended June 30, 2023, and 2022. Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued employee compensation and related expenses $ 5,031 $ 5,752 Accrued research and development expenses 7,451 6,731 Accrued patent expenses 703 1,331 Accrued expenses related to sublicensing revenues 795 596 Other 1,921 1,669 Total $ 15,901 $ 16,079

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 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, the “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 directors seats and to jointly vote with another stockholder on a second board of directors seat. As of June 30, 2023, we have 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 record this investment using the measurement alternative in accordance with ASC 321, Investments–Equity Securities. Under the measurement alternative, our investment in Edge’s convertible preferred stock was initially recorded at its estimated fair value, and the carrying value may be adjusted through earnings upon an impairment or when there is an observable price change involving the same or a similar investment with Edge. As of each of June 30, 2023, and December 31, 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 three months ended June 30, 2023. We did not recognize any revenue in connection with the Edge chRDNA License Agreement for each of the three and six months ended June 30, 2023, and 2022. On May 16, 2023, we entered into an Exclusive License Agreement for Veterinary Therapeutics (CRISPR-Cas9) (the “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 revenues in connection with the Edge Cas9 License Agreement for each of the three and six months ended June 30, 2023. We did not recognize any revenues in connection with the Edge Cas9 License Agreement in 2022.

Leases

Leases	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Leases	Leases Operating Lease Obligations As of March 31, 2023 we had operating leases for our laboratory and office space in Berkeley, California, consisting of approximately 75,000 square feet, with remaining lease terms up to 9.3 years. Certain of our laboratory and office space lease agreements include options to extend the terms for a period of five years and also contain provisions for future rent increases. In addition to base rent, we pay our share of operating expenses and taxes. The components of lease costs, which are included in our statements of operations and comprehensive loss, were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Operating lease cost (1) $ 1,928 $ 1,822 $ 3,812 $ 3,621 Short-term lease cost 62 20 125 83 Total lease cost $ 1,990 $ 1,842 $ 3,937 $ 3,704 (1) Included $0.6 million and $0.5 million of variable lease cost related to operating expenses and taxes for the three months ended June 30, 2023, and 2022, respectively. Included $1.2 million and $1.0 million of variable lease cost related to operating expenses and taxes for the six months ended June 30, 2023, and 2022, respectively. Supplemental information related to our leases was as follows (in thousands): Six Months Ended June 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,058 $ 1,743 The weighted-average remaining lease term and the weighted-average discount rate for our laboratory and office leases were as follows: June 30, December 31, Weighted-average remaining lease term (years) 7.8 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 June 30, 2023 (in thousands): Remainder of 2023 (1) $ 1,364 2024 (2) 3,794 2025 4,475 2026 5,720 2027 5,922 Thereafter 22,116 Total undiscounted lease payments 43,391 Less: imputed interest (16,157) Total discounted lease payments 27,234 Less: current portion of lease liability (1,079) Noncurrent portion of lease liability $ 26,155 (1) Reflects an offset of $0.8 million related to incentives expected to be received in 2023. (2) Reflects an offset of $0.7 million related to incentives expected to be received in 2024.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Research and Development Agreements We enter into various agreements in the ordinary course of business, such as those with suppliers, contract research organizations (“CROs”), contract manufacturing organizations (“CMOs”), clinical trial sites, 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 condensed consolidated financial condition, results of operations, or cash flows. 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 June 30, 2023, and December 31, 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 February 10, 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, Greenhalgh v. Caribou Biosciences, Inc., et al., Case Number 3:23-cv-00609-VC (the “Greenhalgh Case”). The Greenhalgh Case was voluntarily dismissed on March 16, 2023. 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 (the “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 (the “Securities Act”) and Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Additionally, 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 (the “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. We believe these lawsuits are without merit.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Common Stock	Common Stock Common stock reserved for future issuance consisted of the following: As of As of Stock options, issued and outstanding 9,253,848 6,733,074 Stock options, authorized for future issuance 6,246,232 5,833,979 Stock available under our employee stock purchase plan 1,584,538 1,044,518 Unvested restricted stock units and performance-based restricted stock units 233,035 256,146 17,317,653 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 U.S. Securities and Exchange Commission (“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 will be established at the time of such offering and will be described in a prospectus supplement to the Shelf Registration Statement filed with the SEC prior to the completion of any such offering. At-the-market Equity Offering Program On August 9, 2022, we also entered into an Open Market Sale Agreement SM (the “ATM Sales Agreement”) with Jefferies LLC (“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. During the six months ended June 30, 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).

Stock Based Compensation

Stock Based Compensation	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock Based Compensation	Stock-Based Compensation Equity Incentive Plans In July 2021, our board of directors adopted and our stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”) that became effective on July 22, 2021. As of June 30, 2023, we had 6,246,232 shares available for issuance under the 2021 Plan. The following table summarizes stock option activity under our equity incentive plans during the six months ended June 30, 2023: Stock Options Weighted- Weighted- Aggregate Outstanding at December 31, 2022 6,733,074 $ 9.01 8.2 $ 8,203 Options granted 3,022,706 5.79 Options exercised (126,518) 2.77 Options cancelled or forfeited (375,414) 6.59 Outstanding at June 30, 2023 9,253,848 $ 8.14 8.5 $ 1,796 Exercisable at June 30, 2023 3,438,788 $ 7.65 7.6 $ 1,572 Vested and expected to vest at June 30, 2023 9,253,848 $ 8.14 8.5 $ 1,796 *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. Grant Date Fair Value During the three months ended June 30, 2023, and 2022, we granted 486,366 and 495,120 stock options to employees with a weighted average grant date fair value of $2.95 and $4.82, respectively. During the six months ended June 30, 2023, and 2022, we granted 3,022,706 and 834,150 stock options to employees with a weighted average grant date fair value of $3.94 and $5.58, respectively. We estimated the fair value of each employee and non-employee stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Volatility 74.7% to 74.8% 71.9% to 74.1% 74.7% to 75.0% 71.7% to 74.1% Expected term (in years) 6.0 6.0 5.0 to 6.0 5.5 to 6.0 Risk-free interest rate 3.6% to 3.9% 2.8% to 3.4% 3.5% to 4.1% 1.7% to 3.4% Expected dividend yield 0.0% 0.0% 0.0% 0.0% As of June 30, 2023, there was $31.7 million of unrecognized stock-based compensation expense related to employee and non-employee stock options that is expected to be recognized over a weighted-average period of 2.8 years. Restricted Stock Units During the six months ended June 30, 2023, we did not grant any restricted stock units (“RSUs”) or performance-based RSUs (“PSUs”) under the 2021 Plan. A summary of the status of and change in unvested RSUs and PSUs as of June 30, 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, 2023 256,146 $ 10.07 Vested (15,000) 10.64 Forfeited (8,111) 9.90 Unvested, June 30, 2023 233,035 $ 10.04 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 June 30, 2023, the achievement of this milestone was not considered probable and, therefore, no stock-based compensation was recorded. As of June 30, 2023, the total unrecognized stock-based compensation expense related to unvested RSUs was $1.1 million, which is expected to be recognized over the remaining weighted-average vesting period of 1.5 years. As of June 30, 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. We have issued 139,384 shares of common stock under the ESPP as of June 30, 2023. We recorded $0.3 million in accrued liabilities related to contributions withheld as of June 30, 2023. Stock-Based Compensation Expense We recorded stock-based compensation expense related to employee and non-employee equity-based awards grants in our condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development $ 1,551 $ 967 $ 2,860 $ 2,067 General and administrative 2,034 1,951 3,856 3,875 Total $ 3,585 $ 2,918 $ 6,716 $ 5,942 The above stock-based compensation expense related to the following equity-based awards (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Stock options $ 3,202 $ 2,781 $ 6,000 $ 5,711 ESPP 189 66 331 129 RSUs 194 71 385 102 Total $ 3,585 $ 2,918 $ 6,716 $ 5,942 Stock-based compensation expense related to employees was $3.6 million and $2.9 million for the three months ended June 30, 2023, and 2022, respectively. Stock-based compensation expense related to employees was $6.7 million and $5.9 million for the six months ended June 30, 2023, and 2022, respectively. There was no stock-based compensation expense related to non-employees for the three months ended June 30, 2023, and was less than $0.1 million for the three

401(k) Savings Plan

401(k) Savings Plan	6 Months Ended
	Jun. 30, 2023
Retirement Benefits [Abstract]
401(K) Savings plan	401(k) Savings PlanIn 2017, we established a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code of 1986, as amended (the “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 six months ended June 30, 2023, and 2022, we contributed $0.5 million and $0.4 million, respectively, to our 401(k) plan.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesNo income tax expense was recorded during each of the three- and six-month periods ended June 30, 2023, and 2022 due to our operating losses.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	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): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ (29,519) $ (26,697) $ (57,563) $ (45,785) Denominator: Weighted-average common shares outstanding used to compute net loss per share, basic and diluted 61,417,934 60,757,689 61,302,863 60,652,532 Net loss per share, basic and diluted $ (0.48) $ (0.44) $ (0.94) $ (0.75) 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 As of Stock options outstanding 9,253,848 6,610,958 RSUs and PSUs issued and outstanding 233,035 60,000 Shares committed under ESPP 149,350 33,339 9,636,233 6,704,297

Pfizer Investment

Pfizer Investment	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Pfizer Investment	Pfizer Investment On June 29, 2023, we entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with Pfizer, pursuant to which we, in a private placement transaction (the “Pfizer Investment”), agreed to issue and sell 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. 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 with regard to the resale of the shares. Unless otherwise agreed by Pfizer, we have 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 the 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 (the “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. In the event that 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 would 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. Through an information sharing committee, we will 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 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. 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. No revenue from Pfizer was recognized during each of the three- or six-month periods ended June 30, 2023, or 2022. As of June 30, 2023, there was approximately $7.5 million of related party deferred revenue ($2.5 million included in current liabilities and $5.0 million included in long-term liabilities) related to our performance obligations to Pfizer.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In July and August 2023, we issued and sold a total of 22,115,384 shares of our common stock in an underwritten public offering at a price to the public of $6.50 per share, which included the full exercise of the underwriters’ over-allotment option. The total net proceeds from the offering were approximately $134.6 million, after deducting underwriting discounts and commissions and estimated offering expenses. The shares were issued pursuant to the Shelf Registration Statement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and include the accounts of Caribou Biosciences, Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions are eliminated in consolidation.
Use Of Estimates	Use of Estimates The preparation of condensed 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 condensed 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, common stock valuation, stock-based compensation expense, accrued expenses related to research and development activities, valuation of the Memorial Sloan Kettering Cancer Center (“MSKCC”) success payments liability, 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
Segments	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 two financial institutions, and 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 Revenue Accounts Receivable and Contract Assets Three Months Ended Six Months Ended As of As of June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Licensee A 17.1 % 13.8 % 19.5 % 16.1 % 28.4 % 23.8 % Licensee B 36.6 % 68.3 % 41.1 % 55.4 % 45.6 % 36.6 % Licensee C 30.6 % * 15.8 % * * * Total 84.3 % 82.1 % 76.4 % 71.5 % 74.0 % 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 June 30, 2023, or December 31, 2022.
Recent Accounting Pronouncements and New Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“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, and interim reporting periods within fiscal years beginning after December 15, 2023. 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 on our financial statements and related disclosures was not material.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 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 Revenue Accounts Receivable and Contract Assets Three Months Ended Six Months Ended As of As of June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Licensee A 17.1 % 13.8 % 19.5 % 16.1 % 28.4 % 23.8 % Licensee B 36.6 % 68.3 % 41.1 % 55.4 % 45.6 % 36.6 % Licensee C 30.6 % * 15.8 % * * * Total 84.3 % 82.1 % 76.4 % 71.5 % 74.0 % 60.4 % *Less than 10%

Fair Value Measurements and F_2

Fair Value Measurements and Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2023 Total Level 1 Level 2 Level 3 Assets: U.S. Treasury bills ($18,295 included in cash and cash equivalents) $ 159,788 $ 159,788 $ — $ — U.S. government agency bonds 57,010 — 57,010 — Money market fund investments (included in cash and cash equivalents) 47,899 47,899 — — Commercial paper 15,655 — 15,655 — Corporate debt securities 12,169 — 12,169 — Total fair value of assets $ 292,521 $ 207,687 $ 84,834 $ — Liabilities: MSKCC success payments liability $ 1,117 $ — $ — $ 1,117 Total fair value of liabilities $ 1,117 $ — $ — $ 1,117 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	The fair value and amortized cost of cash equivalents and available-for-sale marketable securities by major security type as of June 30, 2023, and December 31, 2022 are presented in the following tables (in thousands): As of June 30, 2023 Amortized Cost Basis Unrealized Gains Unrealized Losses Estimated Fair Value U.S. Treasury bills ($18,295 included in cash and cash equivalents) $ 160,455 $ 16 $ (683) $ 159,788 U.S. government agency bonds 57,442 — (432) 57,010 Money market investments (included in cash equivalents) 47,899 — — 47,899 Commercial paper 15,674 — (19) 15,655 Corporate debt securities 12,187 4 (22) 12,169 Total cash equivalents and marketable securities $ 293,657 $ 20 $ (1,156) $ 292,521 Classified as: Cash and cash equivalents $ 66,194 Marketable securities, short-term 193,038 Marketable securities, long-term 33,289 Total cash equivalents and marketable securities $ 292,521 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 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 and cash equivalents $ 58,338 Marketable securities, short-term 189,325 Marketable securities, long-term 69,373 Total cash equivalents and marketable securities $ 317,036
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 Balance at December 31, 2022 $ 1,651 Change in fair value (534) Balance at June 30, 2023 $ 1,117
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 Fair value of common stock $ 6.28 Risk-free interest rate 3.88% Expected volatility 79% Probability of achieving multiple of Initial Share Price (1) 3.0% to 10.6% Expected term (years) 4.6 to 6.0

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 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 three and six months ended June 30, 2023, and 2022 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 United States $ 3,746 $ 4,183 $ 7,131 $ 6,795 Rest of world 9 9 126 61 Total $ 3,755 $ 4,192 $ 7,257 $ 6,856
Schedule of Changes in Company's Contract Assets and Liabilities	The following table presents changes in our contract assets and liabilities during the six months ended June 30, 2023 (in thousands): Balance as of Additions Deductions Balance as of Accounts receivable $ 202 $ 5,704 $ (5,140) $ 766 Contract assets: Unbilled accounts receivable $ 2,247 $ 3,023 $ (3,789) $ 1,481 Contract liabilities: Deferred revenue, current and long-term $ 25,891 $ 10,326 $ (5,095) $ 31,122

Balance Sheet Items (Tables)

Balance Sheet Items (Tables)	6 Months Ended
	Jun. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Schedule of Other Receivables	Other receivables consisted of the following (in thousands): June 30, December 31, Patent cost reimbursements $ 1,194 $ 1,638 Accrued interest on marketable securities 275 570 Other 26 7 Total $ 1,495 $ 2,215
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 30, December 31, Prepaid contract manufacturing and clinical costs $ 3,228 $ 4,803 Prepaid insurance 248 1,568 Prepaid income taxes 603 431 Other 1,485 1,119 Total $ 5,564 $ 7,921
Schedule of Property and Equipment	Property and equipment, net, consisted of the following (in thousands): June 30, December 31, Lab equipment $ 14,177 $ 12,588 Leasehold improvements 1,993 1,876 Computer equipment 809 709 Furniture and equipment 161 161 Construction in progress 5,115 993 Total property and equipment, gross 22,255 16,327 Less: accumulated depreciation and amortization (6,826) (5,649) Property and equipment, net $ 15,429 $ 10,678
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued employee compensation and related expenses $ 5,031 $ 5,752 Accrued research and development expenses 7,451 6,731 Accrued patent expenses 703 1,331 Accrued expenses related to sublicensing revenues 795 596 Other 1,921 1,669 Total $ 15,901 $ 16,079

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule Of Components Lease Cost	The components of lease costs, which are included in our statements of operations and comprehensive loss, were as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Operating lease cost (1) $ 1,928 $ 1,822 $ 3,812 $ 3,621 Short-term lease cost 62 20 125 83 Total lease cost $ 1,990 $ 1,842 $ 3,937 $ 3,704 (1) Included $0.6 million and $0.5 million of variable lease cost related to operating expenses and taxes for the three months ended June 30, 2023, and 2022, respectively. Included $1.2 million and $1.0 million of variable lease cost related to operating expenses and taxes for the six months ended June 30, 2023, and 2022, respectively.
Schedule Of Supplemental Information Related To Leases	Supplemental information related to our leases was as follows (in thousands): Six Months Ended June 30, 2023 2022 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2,058 $ 1,743 The weighted-average remaining lease term and the weighted-average discount rate for our laboratory and office leases were as follows: June 30, December 31, Weighted-average remaining lease term (years) 7.8 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 June 30, 2023 (in thousands): Remainder of 2023 (1) $ 1,364 2024 (2) 3,794 2025 4,475 2026 5,720 2027 5,922 Thereafter 22,116 Total undiscounted lease payments 43,391 Less: imputed interest (16,157) Total discounted lease payments 27,234 Less: current portion of lease liability (1,079) Noncurrent portion of lease liability $ 26,155 (1) Reflects an offset of $0.8 million related to incentives expected to be received in 2023. (2) Reflects an offset of $0.7 million related to incentives expected to be received in 2024.

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance consisted of the following: As of As of Stock options, issued and outstanding 9,253,848 6,733,074 Stock options, authorized for future issuance 6,246,232 5,833,979 Stock available under our employee stock purchase plan 1,584,538 1,044,518 Unvested restricted stock units and performance-based restricted stock units 233,035 256,146 17,317,653 13,867,717

Stock Based Compensation (Table

Stock Based Compensation (Tables)	6 Months Ended
	Jun. 30, 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 six months ended June 30, 2023: Stock Options Weighted- Weighted- Aggregate Outstanding at December 31, 2022 6,733,074 $ 9.01 8.2 $ 8,203 Options granted 3,022,706 5.79 Options exercised (126,518) 2.77 Options cancelled or forfeited (375,414) 6.59 Outstanding at June 30, 2023 9,253,848 $ 8.14 8.5 $ 1,796 Exercisable at June 30, 2023 3,438,788 $ 7.65 7.6 $ 1,572 Vested and expected to vest at June 30, 2023 9,253,848 $ 8.14 8.5 $ 1,796 *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 non-employee stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Volatility 74.7% to 74.8% 71.9% to 74.1% 74.7% to 75.0% 71.7% to 74.1% Expected term (in years) 6.0 6.0 5.0 to 6.0 5.5 to 6.0 Risk-free interest rate 3.6% to 3.9% 2.8% to 3.4% 3.5% to 4.1% 1.7% to 3.4% Expected dividend yield 0.0% 0.0% 0.0% 0.0%
Schedule of Restricted Stock Units Activity (RSUs)	A summary of the status of and change in unvested RSUs and PSUs as of June 30, 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, 2023 256,146 $ 10.07 Vested (15,000) 10.64 Forfeited (8,111) 9.90 Unvested, June 30, 2023 233,035 $ 10.04
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 and non-employee equity-based awards grants in our condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development $ 1,551 $ 967 $ 2,860 $ 2,067 General and administrative 2,034 1,951 3,856 3,875 Total $ 3,585 $ 2,918 $ 6,716 $ 5,942
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): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Stock options $ 3,202 $ 2,781 $ 6,000 $ 5,711 ESPP 189 66 331 129 RSUs 194 71 385 102 Total $ 3,585 $ 2,918 $ 6,716 $ 5,942

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 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): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ (29,519) $ (26,697) $ (57,563) $ (45,785) Denominator: Weighted-average common shares outstanding used to compute net loss per share, basic and diluted 61,417,934 60,757,689 61,302,863 60,652,532 Net loss per share, basic and diluted $ (0.48) $ (0.44) $ (0.94) $ (0.75)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	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 As of Stock options outstanding 9,253,848 6,610,958 RSUs and PSUs issued and outstanding 233,035 60,000 Shares committed under ESPP 149,350 33,339 9,636,233 6,704,297

Description of the Business, _2

Description of the Business, Organization, and Liquidity - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended				6 Months Ended
	Aug. 08, 2023 USD ($) shares	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2023 USD ($) subsidiary	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Subsequent Event [Line Items]
Number of subsidiaries | subsidiary						4
Accumulated deficit		$ 254,778				$ 254,778		$ 197,215
Net loss		(29,519)	$ (28,044)	$ (26,697)	$ (19,088)	(57,563)	$ (45,785)
Cash generated in operating activities						(43,124)	$ (43,546)
Cash, cash equivalents and short term marketable securities		$ 292,500				$ 292,500
Subsequent Event | Public Stock Offering
Subsequent Event [Line Items]
Common stock shares sold (in shares) | shares	22,115,384
Aggregate offering price (up to)	$ 134,600

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	6 Months Ended
	Jun. 30, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
Accounting Policies [Abstract]
Number of operating segment	1
Number of reportable segment	1
Allowance for doubtful accounts | $	$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Concentration of Credit Risk and other Uncertainties (Details) - Customer Concentration Risk	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Revenue Benchmark | Major Customers
Concentration Risk [Line Items]
Total	84.30%	82.10%	76.40%	71.50%
Revenue Benchmark | Licensee A
Concentration Risk [Line Items]
Total	17.10%	13.80%	19.50%	16.10%
Revenue Benchmark | Licensee B
Concentration Risk [Line Items]
Total	36.60%	68.30%	41.10%	55.40%
Revenue Benchmark | Licensee C
Concentration Risk [Line Items]
Total	30.60%		15.80%
Accounts Receivable | Major Customers
Concentration Risk [Line Items]
Total			74%		60.40%
Accounts Receivable | Licensee A
Concentration Risk [Line Items]
Total			28.40%		23.80%
Accounts Receivable | Licensee B
Concentration Risk [Line Items]
Total			45.60%		36.60%

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Financial Instruments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Liabilities:
Cash and cash equivalents	$ 66,194	$ 58,338	$ 112,146
U.S. government agency bonds
Liabilities:
Cash and cash equivalents		3,976
Commercial paper
Liabilities:
Cash and cash equivalents		26,669
Fair Value, Recurring
Assets:
Assets fair value	292,521	317,036
Liabilities:
Liabilities fair value	1,117	1,651
Fair Value, Recurring | U.S. Treasury bills
Assets:
Assets fair value	159,788	91,966
Fair Value, Recurring | U.S. government agency bonds
Assets:
Assets fair value	57,010	63,659
Fair Value, Recurring | Commercial paper
Assets:
Assets fair value	15,655	96,899
Fair Value, Recurring | Money market funds
Assets:
Assets fair value	47,899	27,693
Fair Value, Recurring | Corporate debt securities
Assets:
Assets fair value	12,169	36,819
Fair Value, Recurring | MSKCC success payments liability
Liabilities:
Liabilities fair value	1,117	1,651
Fair Value, Recurring | Level 1
Assets:
Assets fair value	207,687	119,659
Liabilities:
Liabilities fair value	0	0
Fair Value, Recurring | Level 1 | U.S. Treasury bills
Assets:
Assets fair value	159,788	91,966
Fair Value, Recurring | Level 1 | U.S. government agency bonds
Assets:
Assets fair value	0	0
Fair Value, Recurring | Level 1 | Commercial paper
Assets:
Assets fair value	0	0
Fair Value, Recurring | Level 1 | Money market funds
Assets:
Assets fair value	47,899	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	84,834	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 | U.S. government agency bonds
Assets:
Assets fair value	57,010	63,659
Fair Value, Recurring | Level 2 | Commercial paper
Assets:
Assets fair value	15,655	96,899
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	12,169	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	1,117	1,651
Fair Value, Recurring | Level 3 | U.S. Treasury bills
Assets:
Assets fair value	0	0
Fair Value, Recurring | Level 3 | U.S. government agency bonds
Assets:
Assets fair value	0	0
Fair Value, Recurring | Level 3 | Commercial paper
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	$ 1,117	$ 1,651

Fair Value Measurements and F_4

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	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost Basis	$ 293,657	$ 318,555
Cash and cash equivalents, Amortized Cost Basis	66,194	58,338	$ 112,146
Unrealized Gains	20	32
Unrealized Losses	(1,156)	(1,551)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value	292,521	317,036
Marketable securities, short-term	193,038	189,325
Marketable securities, long-term	33,289	69,373
Commercial paper
Debt Securities, Available-for-Sale [Line Items]
Cash and cash equivalents, Amortized Cost Basis		26,669
Money market funds
Debt Securities, Available-for-Sale [Line Items]
Cash and cash equivalents, Amortized Cost Basis	47,899	27,693
Cash and cash equivalents, Estimated Fair Value	47,899	27,693
U.S. Treasury bills
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost Basis	160,455
Available-for-sale marketable securities, Amortized Cost Basis		92,910
Cash and cash equivalents, Amortized Cost Basis	18,295
Unrealized Gains	16	1
Unrealized Losses	(683)	(945)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value	159,788
Available-for-sale marketable securities, Estimated Fair Value		91,966
U.S. government agency bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost Basis		63,926
Available-for-sale marketable securities, Amortized Cost Basis	57,442
Unrealized Gains	0	25
Unrealized Losses	(432)	(292)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value		63,659
Available-for-sale marketable securities, Estimated Fair Value	57,010
Commercial paper
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost Basis		97,024
Available-for-sale marketable securities, Amortized Cost Basis	15,674
Unrealized Gains	0	6
Unrealized Losses	(19)	(131)
Available-for-sale marketable securities and cash and cash equivalents, Estimated Fair Value		96,899
Available-for-sale marketable securities, Estimated Fair Value	15,655
Corporate debt securities
Debt Securities, Available-for-Sale [Line Items]
Available-for-sale marketable securities, Amortized Cost Basis	12,187	37,002
Unrealized Gains	4	0
Unrealized Losses	(22)	(183)
Available-for-sale marketable securities, Estimated Fair Value	$ 12,169	$ 36,819

Fair Value Measurements and F_5

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Change in Fair Value of Financial Liability (Details) - MSKCC success payments liability - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Change in fair value	$ 300	$ 1,100	$ 500	$ 2,600
Level 3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at December 31, 2022			1,651
Change in fair value			(534)
Balance at June 30, 2023	$ 1,117		$ 1,117

Fair Value Measurements and F_6

Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
MSKCC success payments liability
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Change in fair value	$ 0.3	$ 1.1	$ 0.5	$ 2.6

Fair Value Measurements and F_7

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, 2022 $ / shares	Jun. 30, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock value per share (in dollars per share)	$ 5.1914
Fair value of common stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability interest	6.28	4.25
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability interest	0.000388
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability interest	0.0079
Probability of achieving multiple of Initial Share Price(1) | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability interest	0.030
Probability of achieving multiple of Initial Share Price(1) | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability interest	0.106
Expected term (years) | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability assumptions term	4 years 7 months 6 days
Expected term (years) | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Success payment liability assumptions term	6 years

Significant Agreements - Additi

Significant Agreements - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue, current	$ 12,962,000		$ 12,962,000		$ 9,937,000
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	18,162,000		18,162,000		15,954,000
Accounts receivable	766,000		766,000		202,000
Contract assets	1,481,000		1,481,000		2,247,000
Research and development	26,503,000	$ 22,579,000	52,212,000	$ 36,503,000
General and administrative	10,120,000	10,044,000	19,029,000	19,637,000
Collaboration and License Agreement with AbbVie
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront cash payment received						$ 30,000,000
Deferred revenue, current	10,000,000		10,000,000		9,400,000
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	10,800,000		10,800,000		13,300,000
Revenues	1,400,000	2,900,000	3,000,000	3,800,000
Accounts receivable	600,000		600,000		0
Contract assets	500,000		500,000		$ 900,000
Intellia Therapeutics, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development	400,000	200,000	800,000	500,000
General and administrative	1,000,000	1,200,000	1,800,000	3,700,000
Future payments for milestones	161,200,000		161,200,000
Intellia Therapeutics, Inc. | Patents
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Reduction in general and administrative expenses	$ 700,000	$ 700,000	$ 1,100,000	$ 2,100,000

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation Of Revenue [Line Items]
Revenue	$ 3,755	$ 4,192	$ 7,257	$ 6,856
United States
Disaggregation Of Revenue [Line Items]
Revenue	3,746	4,183	7,131	6,795
Rest of world
Disaggregation Of Revenue [Line Items]
Revenue	$ 9	$ 9	$ 126	$ 61

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation Of Revenue [Line Items]
Decrease in unbilled accounts receivable				$ (765)	$ 606
Contract with customer, increase for new contract	$ 7,500			7,500
Revenue recognized included in the opening contract liabilities balance				2,400	2,500
Transaction price allocated to the remaining performance obligations	$ 43,900	$ 43,900		43,900
Point in Time
Disaggregation Of Revenue [Line Items]
Revenue recognized, performance obligation, amount		2,400	$ 1,300	4,300	3,100
Over Time
Disaggregation Of Revenue [Line Items]
Revenue recognized, performance obligation, amount		$ 1,400	$ 2,900	$ 3,000	$ 3,800

Revenue - Schedule of Changes i

Revenue - Schedule of Changes in Company's Contract Assets and Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Accounts receivable
Accounts receivable, Beginning Balance	$ 202
Accounts receivable, Additions	5,704
Accounts receivable, Deductions	(5,140)
Accounts receivable, Ending Balance	766
Contract assets:
Unbilled accounts receivable, Beginning Balance	2,247
Unbilled accounts receivable, Additions	3,023
Unbilled accounts receivable, Deductions	(3,789)
Unbilled accounts receivable, Ending Balance	1,481
Contract liabilities:
Deferred revenue, current and long-term, Beginning Balance	25,891
Deferred revenue, current and long-term, Additions	10,326
Deferred revenue, current and long-term, Deductions	(5,095)
Deferred revenue, current and long-term, Ending Balance	$ 31,122

Revenue - Additional Informat_2

Revenue - Additional Information (Details1) $ in Millions	Jun. 30, 2023 USD ($)
Disaggregation Of Revenue [Line Items]
Remaining performance obligations	$ 43.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-07-01
Disaggregation Of Revenue [Line Items]
Remaining performance obligations	$ 13
Remaining performance obligation, expected timing of satisfaction, period	12 months

Balance Sheet Items - Schedule

Balance Sheet Items - Schedule of Other Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Patent cost reimbursements	$ 1,194	$ 1,638
Accrued interest on marketable securities	275	570
Other	26	7
Total	$ 1,495	$ 2,215

Balance Sheet Items - Schedul_2

Balance Sheet Items - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepaid contract manufacturing and clinical costs	$ 3,228	$ 4,803
Prepaid insurance	248	1,568
Prepaid income taxes	603	431
Other	1,485	1,119
Total	$ 5,564	$ 7,921

Balance Sheet Items - Schedul_3

Balance Sheet Items - Schedule of Property And Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 22,255	$ 16,327
Less: accumulated depreciation and amortization	(6,826)	(5,649)
Property and equipment, net	15,429	10,678
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	14,177	12,588
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,993	1,876
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	809	709
Furniture and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	161	161
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 5,115	$ 993

Balance Sheet Items - Additiona

Balance Sheet Items - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization expense related to property and equipment	$ 0.6	$ 0.4	$ 1.2	$ 0.7

Balance Sheet Items - Summary o

Balance Sheet Items - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued employee compensation and related expenses	$ 5,031	$ 5,752
Accrued research and development expenses	7,451	6,731
Accrued patent expenses	703	1,331
Accrued expenses related to sublicensing revenues	795	596
Other	1,921	1,669
Total	$ 15,901	$ 16,079

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended
	May 15, 2020	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	May 16, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Carrying value of investment		$ 7,766,000		$ 7,766,000			$ 7,698,000
Exercise option, term						3 years
Revenue		3,755,000	$ 4,192,000	7,257,000	$ 6,856,000
Related Party
Related Party Transaction [Line Items]
Revenue		1,150,000	$ 0	1,150,000	$ 0
Convertible Preferred Stock | Private Company License Agreement
Related Party Transaction [Line Items]
Convertible preferred stock issued (in shares)	7,500,000
Fair value of convertible preferred stock	$ 7,500,000
Carrying value of investment		$ 7,500,000		$ 7,500,000			$ 7,500,000

Leases - Additional Information

Leases - Additional Information (Details)	Mar. 31, 2023 ft²
Commitments and Contingencies Disclosure [Abstract]
Area of real estate property (in square feet)	75,000
Remaining lease term (in years)	9 years 3 months 18 days
Lease renewal term (in years)	5 years

Leases - Schedule Of Components

Leases - Schedule Of Components Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 1,928	$ 1,822	$ 3,812	$ 3,621
Short-term lease cost	62	20	125	83
Total lease cost	1,990	1,842	3,937	3,704
Variable lease cost	$ 600	$ 500	$ 1,200	$ 1,000

Leases - Schedule Of Supplement

Leases - Schedule Of Supplemental Information Related To Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 2,058	$ 1,743
Operating lease, weighted average remaining lease term	7 years 9 months 18 days		8 years 3 months 18 days
Weighted-average discount rate	11.30%		11.30%

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Commitments Under Lease Contracts (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2023	$ 1,364
2024	3,794
2025	4,475
2026	5,720
2027	5,922
Thereafter	22,116
Total undiscounted lease payments	43,391
Less: imputed interest	(16,157)
Total discounted lease payments	27,234
Less: current portion of lease liability	(1,079)	$ (966)
Lease liabilities, non-current	26,155	$ 26,780
Expected incentive offset in first year	800
Expected incentive offset in second year	$ 700

Common Stock - Schedule of Comm

Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) - USD ($) $ / shares in Units, $ in Millions		6 Months Ended
	Aug. 09, 2022	Jun. 30, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		17,317,653	13,867,717
Authorized amount under shelf registration	$ 400
At The Market ATM Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate offering price (up to)		$ 1
Common stock shares sold (in shares)		168,635
Public offering price (in dollars per share)		$ 7.32
Aggregate gross proceeds		$ 1.2
At The Market ATM Offering | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate offering price (up to)	$ 100
Stock options, issued and outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		9,253,848	6,733,074
Stock options, authorized for future issuance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		6,246,232	5,833,979
Stock available under our employee stock purchase plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		1,584,538	1,044,518
Unvested restricted stock units and performance-based restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		233,035	256,146

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		23 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	17,317,653		17,317,653		17,317,653	13,867,717
Stock options granted during period (in shares)			3,022,706
Unrecognized stock based-compensation expenses	$ 31,700		$ 31,700		$ 31,700
Weighted-average period			2 years 9 months 18 days
Accrued liabilities	300		$ 300		$ 300
Stock-based compensation expense	$ 3,585	$ 2,918	$ 6,716	$ 5,942
Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted during period (in shares)	486,366	495,120	3,022,706	834,150
Stock-based compensation expense	$ 3,600	$ 2,900	$ 6,700	$ 5,900
Non-Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 0	$ 100	$ 0	$ 100
Employee and Non-Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 2.95	$ 4.82	$ 3.94	$ 5.58
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	6,246,232		6,246,232		6,246,232
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock in connection with at-the-market offering, net of offering expenses (in shares)					139,384
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period			1 year 6 months
Unrecognized stock-based compensation expense	$ 1,100		$ 1,100		$ 1,100
Stock-based compensation expense	194	$ 71	385	$ 102
Performance Restricted Stock Units (PRSU)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 600		$ 600		$ 600

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Stock Options
Outstanding, Beginning Balance (in shares) | shares	6,733,074
Granted (in shares) | shares	3,022,706
Exercised (in shares) | shares	(126,518)
Cancelled or forfeited (in shares) | shares	(375,414)
Outstanding, Ending Balance (in shares) | shares	9,253,848	6,733,074
Exercisable (in shares) | shares	3,438,788
Vested and expected to vest (in shares) | shares	9,253,848
Weighted- Average Exercise Price
Outstanding, Beginning Balance (in dollars per share) | $ / shares	$ 9.01
Granted (in dollars per share) | $ / shares	5.79
Exercised (in dollars per share) | $ / shares	2.77
Cancelled or forfeited (in dollars per share) | $ / shares	6.59
Outstanding, Ending Balance (in dollars per share) | $ / shares	8.14	$ 9.01
Exercisable (in dollars per share) | $ / shares	7.65
Vested and expected to vest (in dollars per share) | $ / shares	$ 8.14
Weighted- Average Remaining Contractual Term (years)
Outstanding (in years)	8 years 6 months	8 years 2 months 12 days
Exercisable (in years)	7 years 7 months 6 days
Vested and expected to vest (in years)	8 years 6 months
Aggregate Intrinsic Value (in thousands)*
Outstanding | $	$ 1,796	$ 8,203
Exercisable | $	1,572
Vested and expected to vest | $	$ 1,796

Stock Based Compensation - Sc_2

Stock Based Compensation - Schedule of Estimated Fair Value of Stock Options on the Grant Date Using Black-Scholes Option-Pricing Model (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years	6 years
Expected dividend yield	0%	0%	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	74.70%	71.90%	74.70%	71.70%
Expected term (in years)			5 years	5 years 6 months
Risk-free interest rate	3.60%	2.80%	3.50%	1.70%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	74.80%	74.10%	75%	74.10%
Expected term (in years)			6 years	6 years
Risk-free interest rate	3.90%	3.40%	4.10%	3.40%

Stock Based Compensation - Sc_3

Stock Based Compensation - Schedule of Restricted Stock Units Activity (RSUs) (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Number of Shares Underlying Outstanding RSUs and PSUs
Vested | shares	(15,000)
Weighted-Average Grant Date Fair Value per RSU and PSU
Vested, Weighted-Average Grant Date Fair Value per RSU and PRSU (in dollars per share) | $ / shares	$ 10.64
Restricted Stock Units RSU and Performance-Based RSUs
Number of Shares Underlying Outstanding RSUs and PSUs
Unvested, January 1, 2023 (in shares) | shares	256,146
Forfeited | shares	(8,111)
Unvested, June 30, 2023 (in shares) | shares	233,035
Weighted-Average Grant Date Fair Value per RSU and PSU
Unvested, Weighted-Average Grant Date Fair Value per RSU, Beginning Balance (in dollars per share) | $ / shares	$ 10.07
Forfeited, Weighted-Average Grant Date Fair Value per RSU and PRSU (in dollars per share) | $ / shares	9.90
Unvested, Weighted-Average Grant Date Fair Value per RSU, Ending Balance (in dollars per share) | $ / shares	$ 10.04

Stock Based Compensation - Sc_4

Stock Based Compensation - Schedule of Stock Option Expenses Related to Employee and Non-Employee Stock Options Granted (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 3,585	$ 2,918	$ 6,716	$ 5,942
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	1,551	967	2,860	2,067
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 2,034	$ 1,951	$ 3,856	$ 3,875

Stock Based Compensation - Sc_5

Stock Based Compensation - Schedule of Stock-based Compensation Expense Related to Equity-Based Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 3,585	$ 2,918	$ 6,716	$ 5,942
Employee and Non-Employee
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Weighted average grant date fair value (in dollars per share)	$ 2.95	$ 4.82	$ 3.94	$ 5.58
Stock options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 3,202	$ 2,781	$ 6,000	$ 5,711
ESPP
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	189	66	331	129
RSUs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$ 194	$ 71	$ 385	$ 102

401(k) Savings Plan - Additiona

401(k) Savings Plan - Additional Information (Details) - 2017 Plan - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, Employer matching contribution percent of match	4%
Employer contribution	$ 0.5	$ 0.4

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 0	$ 0	$ 0

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net loss	$ (29,519)	$ (28,044)	$ (26,697)	$ (19,088)	$ (57,563)	$ (45,785)
Denominator:
Weighted-average common shares outstanding, basic (in shares)	61,417,934		60,757,689		61,302,863	60,652,532
Weighted-average common shares outstanding, diluted (in shares)	61,417,934		60,757,689		61,302,863	60,652,532
Net loss per share, basic (in dollars per share)	$ (0.48)		$ (0.44)		$ (0.94)	$ (0.75)
Net loss per share, diluted (in dollars per share)	$ (0.48)		$ (0.44)		$ (0.94)	$ (0.75)

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of the Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,636,233	6,704,297
Restricted Stock Units RSU and Performance-Based RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	233,035	60,000
Stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	9,253,848	6,610,958
Shares Committed Under ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	149,350	33,339

Pfizer Investment (Details)

Pfizer Investment (Details) - USD ($)		3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 29, 2023	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001		$ 0.0001			$ 0.0001
Term of agreement	36 months	36 months		36 months
Period of right of first negotiation	30 days	30 days		30 days
Proceeds from issuance of common stock in a private placement with Pfizer	$ 17,500,000			$ 17,450,000	$ 0
Contract with customer, increase for new contract	7,500,000			7,500,000
Revenue		$ 3,755,000	$ 4,192,000	7,257,000	6,856,000
Contract with customer, liability	31,122,000	31,122,000		31,122,000			$ 25,891,000
Deferred revenue ($2,487 and $150 from related party, respectively)	12,962,000	12,962,000		12,962,000			9,937,000
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	18,162,000	18,162,000		18,162,000			15,954,000
Related Party
Subsidiary, Sale of Stock [Line Items]
Revenue		1,150,000	0	1,150,000	0
Deferred revenue ($2,487 and $150 from related party, respectively)	2,487,000	2,487,000		2,487,000			150,000
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	4,973,000	4,973,000		4,973,000			$ 0
Pfizer
Subsidiary, Sale of Stock [Line Items]
Revenue		0	$ 0	0	$ 0
Pfizer | Related Party
Subsidiary, Sale of Stock [Line Items]
Contract with customer, liability	7,500,000	7,500,000		7,500,000
Deferred revenue ($2,487 and $150 from related party, respectively)	2,500,000	2,500,000		2,500,000
Deferred revenue, net of current portion ($4,973 and $0 from related party, respectively)	$ 5,000,000	$ 5,000,000		$ 5,000,000
Pfizer
Subsidiary, Sale of Stock [Line Items]
Investment owned, percentage						4.99%
Private Placement
Subsidiary, Sale of Stock [Line Items]
Common stock shares sold (in shares)	4,690,431
Common stock price per share (in dollars per share)	$ 5.33	$ 5.33		$ 5.33
Aggregate offering price (up to)	$ 25,000,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	Aug. 08, 2023	Jun. 30, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Common stock, shares issued (in shares)		66,100,039	61,029,184
Public Stock Offering | Subsequent Event
Subsequent Event [Line Items]
Public offering price (in dollars per share)	$ 6.50
Common stock shares sold (in shares)	22,115,384
Aggregate offering price (up to)	$ 134.6