Sana Biotechnology (SANA) 10-K 16 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Registrant Name	Sana Biotechnology, Inc.
Entity Central Index Key	0001770121
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		191,361,182
Entity Public Float			$ 1.2
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-39941
Entity Tax Identification Number	83-1381173
Entity Address Address Line1	188 East Blaine Street
Entity Address, Address Line Two	Suite 400
Entity Address City Or Town	Seattle
Entity Address State Or Province	WA
Entity Address Postal Zip Code	98102
City Area Code	206
Local Phone Number	701-7914
Document Annual Report	true
Document Transition Report	false
Entity Incorporation State Country Code	DE
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	SANA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	false
Auditor Name	Ernst & Young LLP
Auditor Location	Seattle, Washington
Auditor Firm ID	42
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s definitive Proxy Statement relating to its 2023 Annual Meeting of Stockholders (Proxy Statement) are incorporated by reference into Part III of this Annual Report on Form 10-K (Annual Report) where indicated. The Proxy Statement will be filed with the U.S. Securities and Exchange Commission within 120 days after the end of the fiscal year to which this Annual Report relates.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 176,765	$ 253,029
Marketable securities	247,198	297,967
Restricted cash	6,100
Prepaid expenses and other current assets	14,374	7,105
Total current assets	444,437	558,101
Long-term marketable securities	10,051	195,881
Property and equipment, net	66,917	65,464
Operating lease right-of-use assets	92,486	96,320
Long-term restricted cash	4,408	8,819
Intangible asset	59,195	59,195
Goodwill	140,627	140,627
Other non-current assets	4,599	5,000
TOTAL ASSETS	822,720	1,129,407
Current liabilities:
Accounts payable	2,857	2,219
Accrued compensation	26,362	21,131
Accrued expenses and other current liabilities	14,547	10,344
Operating lease liabilities	12,393	9,159
Contingent consideration	55,345	51,382
Success payment liabilities		5,000
Total current liabilities	111,504	99,235
Operating lease liabilities, net of current portion	95,860	101,784
Contingent consideration, net of current portion	95,034	102,361
Success payment liabilities, net of current portion	21,007	97,525
Total liabilities	323,405	400,905
Commitments and contingencies (Note 9)
Stockholders' equity:
Preferred stock, $0.0001 par value; 50,000 shares authorized; zero shares issued and outstanding as of December 31, 2022 and 2021, respectively
Common stock, $0.0001 par value; 750,000 shares authorized; 191,022 and 184,929 shares issued and outstanding as of December 31, 2022 and 2021, respectively	19	18
Additional paid-in capital	1,558,459	1,515,210
Accumulated other comprehensive loss	(4,327)	(1,366)
Accumulated deficit	(1,054,836)	(785,360)
Total stockholders' equity	499,315	728,502
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 822,720	$ 1,129,407

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	191,022,000	184,929,000
Common stock, shares outstanding	191,022,000	184,929,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 285,885	$ 248,626	$ 132,944
Research and development related success payments and contingent consideration	(84,882)	57,873	124,935
General and administrative	71,561	50,410	28,270
Total operating expenses	272,564	356,909	286,149
Loss from operations	(272,564)	(356,909)	(286,149)
Interest income, net	3,762	676	747
Other income (expense), net	(674)	305	97
Net loss	$ (269,476)	$ (355,928)	$ (285,305)
Net loss per common share - basic	$ (1.43)	$ (2.14)	$ (21.92)
Net loss per common share - diluted	$ (1.43)	$ (2.14)	$ (21.92)
Weighted-average number of common shares - basic	188,344	166,433	13,014
Weighted-average number of common shares - diluted	188,344	166,433	13,014

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (269,476)	$ (355,928)	$ (285,305)
Other comprehensive loss, net of tax:
Unrealized gain (loss) on marketable securities, net	(2,961)	(1,396)	4
Total comprehensive loss	$ (272,437)	$ (357,324)	$ (285,301)

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	IPO	At The Market Offering	Convertible Preferred Stock	Common Stock	Common Stock IPO	Common Stock At The Market Offering	Additional Paid-in Capital	Additional Paid-in Capital IPO	Additional Paid-in Capital At The Market Offering	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ (142,542)				$ 1			$ 1,558			$ 26	$ (144,127)
Beginning balance (in shares) at Dec. 31, 2019				106,890
Beginning balance at Dec. 31, 2019				$ 417,359
Beginning balance (in shares) at Dec. 31, 2019					10,003
Issuance of Series B convertible preferred stock, net of $33 in issuance costs				$ 435,538
Issuance of convertible preferred stock, net of issuance costs, (in shares)				27,223
Issuance of common stock in connection with license agreements	680							680
'Issuance of common stock in connection with license agreement (in shares)					100
Vesting of restricted stock	1				$ 1
Vesting of restricted stock (in shares)					5,964
Stock-based compensation	5,829							5,829
Exercise of stock options	149							149
Exercise of stock options (in shares)					103
Unrealized gain (loss) on marketable securities, net	4										4
Net loss	(285,305)											(285,305)
Ending balance at Dec. 31, 2020	(421,184)				$ 2			8,216			30	(429,432)
Ending balance (in shares) at Dec. 31, 2020				134,113
Ending balance at Dec. 31, 2020				$ 852,897
Ending balance (in shares) at Dec. 31, 2020					16,170
Conversion of convertible preferred stock into common stock upon initial public offering	852,897				$ 13			852,884
Conversion of convertible preferred stock into common stock, upon initial public offering (in shares)				(134,113)
Conversion of convertible preferred stock into common stock, upon initial public offering (in shares)					134,113
Issuance of common stock, net of offering costs		$ 626,405				$ 3			$ 626,402
Issuance of common stock, net of offering costs (in shares)						27,025
Vesting of restricted stock (in shares)					5,916
Stock-based compensation	22,362							22,362
Exercise of stock options	3,167							3,167
Exercise of stock options (in shares)					1,586
Issuance of common stock related to employee stock purchase plan	2,179							2,179
Issuance of common stock related to employee stock purchase plan, Shares					119
Unrealized gain (loss) on marketable securities, net	(1,396)										(1,396)
Net loss	(355,928)											(355,928)
Ending balance at Dec. 31, 2021	$ 728,502				$ 18			1,515,210			(1,366)	(785,360)
Ending balance (in shares) at Dec. 31, 2021	184,929				184,929
Issuance of common stock, net of offering costs			$ 601							$ 601
Issuance of common stock, net of offering costs (in shares)							149
Vesting of restricted stock	$ 1				$ 1
Vesting of restricted stock (in shares)					4,395
Stock-based compensation	38,337							38,337
Exercise of stock options	$ 2,253							2,253
Exercise of stock options (in shares)	1,062				1,062
Issuance of common stock related to employee stock purchase plan	$ 2,058							2,058
Issuance of common stock related to employee stock purchase plan, Shares					487
Unrealized gain (loss) on marketable securities, net	(2,961)										(2,961)
Net loss	(269,476)											(269,476)
Ending balance at Dec. 31, 2022	$ 499,315				$ 19			$ 1,558,459			$ (4,327)	$ (1,054,836)
Ending balance (in shares) at Dec. 31, 2022	191,022				191,022

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
IPO
Issuance of common stock, net of offering costs		$ 49,220
At The Market Offering
Issuance of common stock, net of offering costs	$ 625
Series B Convertible Preferred Stock
Convertible preferred stock, issuance costs			$ 33

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES:
Net loss	$ (269,476)	$ (355,928)	$ (285,305)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	15,625	11,070	5,921
Stock-based compensation expense	38,337	22,362	5,828
Change in the estimated fair value of contingent consideration	(3,364)	31,842	52,793
Change in the estimated fair value of success payment liabilities	(81,518)	26,031	72,142
Non-cash expense for operating lease right-of-use assets	12,106	6,844	4,250
Other non-cash items, net	(9,302)	(3,076)	233
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(5,988)	(861)	(1,436)
Operating lease right-of-use assets and liabilities	1,562	5,088	91
Accounts payable	1,058	(266)	1,982
Accrued expenses and other liabilities	10,910	5,840	5,519
Net cash used in operating activities	(290,050)	(251,054)	(137,982)
INVESTING ACTIVITIES:
Purchases of marketable securities	(78,688)	(491,387)	(387,432)
Proceeds from maturities of marketable securities	310,126	280,025	158,741
Purchases of property and equipment	(20,876)	(29,862)	(23,872)
Other investing activities		(4,574)
Net cash provided by (used in) investing activities	210,562	(245,798)	(252,563)
FINANCING ACTIVITIES:
Proceeds from initial public offering, net of issuance costs		626,405
Proceeds from issuance of convertible preferred stock, net of issuance costs			435,538
Proceeds from employee stock purchase plan and exercise of stock options, net	4,312	5,346	149
Proceeds from at the market offering of common stock, net of issuance costs	601
Net cash provided by financing activities	4,913	631,751	435,687
Net (decrease) increase in cash, cash equivalents, and restricted cash	(74,575)	134,899	45,142
Cash, cash equivalents, and restricted cash at beginning of period	261,848	126,949	81,807
Cash, cash equivalents, and restricted cash at end of period	187,273	261,848	126,949
RECONCILITION OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	176,765	253,029	124,806
Restricted cash	6,100
Long-term restricted cash	4,408	8,819	2,143
Total cash, cash equivalents, and restricted cash	187,273	261,848	126,949
SUPPLEMENTAL CASH FLOW INFORMATION:
Operating lease right-of-use assets obtained in exchange for lease obligations	21,073	39,996	26,521
Purchases of property and equipment included in accounts payable and accrued liabilities	1,234	3,015	3,140
Cash received for amounts related to tenant improvement allowances	2,014	$ 5,445	$ 91
Remeasurement of operating lease right-of-use asset for lease modification	$ (12,801)

Organization

Organization	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Organization	1. Organization Sana Biotechnology, Inc. (the Company or Sana) is a biotechnology company focusing on utilizing engineered cells as medicines. The Company’s operations to date have included identifying and developing potential product candidates, executing preclinical studies, establishing manufacturing capabilities, preparing for clinical trials of our product candidates, acquiring technology, organizing and staffing the Company, business planning, establishing and maintaining the Company’s intellectual property portfolio, raising capital, and providing general and administrative support for these operations. Liquidity and capital resources The Company is subject to a number of risks and uncertainties similar to other biotechnology companies in the development stage, including, but not limited to, those related to the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, the need to obtain marketing approval for its product candidates, building out internal and external manufacturing capabilities, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s products, the need to protect the Company’s intellectual property and proprietary technologies, and the need to attract and retain key scientific and management personnel. If the Company does not successfully commercialize or partner any of its product candidates, it will be unable to generate product revenue or achieve profitability. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations with the proceeds from additional equity or debt financings or capital obtained in connection with strategic collaborations or licensing or other arrangements. In the event that additional financing is required, the Company may not be able to raise it on terms acceptable to it or at all. In November 2022, the Company underwent a portfolio prioritization and corporate restructuring designed to optimize development of programs at or nearing clinical development, to continue investments in core research platforms and innovation, and to maintain a strong balance sheet. That process was substantially completed in 2022 and resulted in a reduction of the Company’s workforce by approximately15%. During the year ended December 31, 2022, the Company recognized $6.8 million of expenses related to employee severance, benefits, and related costs, and a non-cash stock-based compensation charge of $1.9 million related to equity awards for employees impacted by the restructuring in general and administrative expense. In August 2022, the Company entered a sales agreement with Cowen and Company, LLC (Cowen), acting as sales agent, pursuant to which it may offer and sell through Cowen shares of the Company’s common stock having an aggregate offering price of up to $150.0 million from time to time in a series of one or more at the market equity offerings (collectively, the ATM facility). As of December 31, 2022, the Company had raised approximately $0.6 million in net proceeds under the ATM facility. In February 2021, the Company successfully completed its initial public offering (IPO) of its common stock. In connection with its IPO, the Company issued 27.0 million shares of its common stock, including 3.5 million shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a price of $25.00 per share, and received $626.4 million in net proceeds, after deducting underwriting discounts and commissions of $45.2 million and offering expenses of $4.0 million. The Company has incurred operating losses each year since inception and expects such losses to continue for the foreseeable future. As of December 31, 2022, the Company had cash, cash equivalents, and marketable securities of $434.0 million, and an accumulated deficit of $1.1 billion, which includes non-cash charges related to the revaluation of the success payment liabilities and contingent consideration of $18.6 million and $99.1 million, respectively.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies Basis of presentation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (GAAP). Certain prior period amounts have been reclassified to conform to current period presentation. Use of estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates. The most significant estimates in the Company’s consolidated financial statements relate to success payment liabilities, contingent consideration, business combinations, accrued expenses, and operating lease right of use assets and liabilities. Cash and cash equivalents Cash and cash equivalents include cash and highly liquid investments with original maturities of three months or less at acquisition. Cash equivalents include investments in money market funds with commercial banks and financial institutions and are stated at fair value. Marketable securities Marketable securities are classified as available-for-sale debt securities and are carried at fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities. Investments in securities with maturities of less than one year, or those for which management intends to use to fund current operations, are included in current assets. Unrealized gains and losses that are deemed to be temporary in nature are reported as a component of accumulated comprehensive income (loss). Amortization, accretion, and dividends are included in other income (expense), net on the consolidated statement of operations. The cost of securities sold is based on the specific-identification method. Each reporting period, the Company evaluates whether declines in fair value below carrying value are due to expected credit losses, as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs. Expected credit losses are recorded as an allowance through other income (expense), net. Concentrations of credit risk and off-balance sheet risk The Company maintains its cash, cash equivalents, and marketable securities with high quality, accredited financial institutions. These amounts, at times, may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to significant risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements. Fair value measurement The Company accounts for certain assets and liabilities at fair value and is required to disclose information that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The hierarchy applies only to the valuation inputs used to determine the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. The Company’s financial instruments include cash and cash equivalents, short- and long-term marketable securities, accounts payable, contingent consideration, success payment liabilities, and other accrued liabilities. The carrying amounts of cash, cash equivalents, accounts payable, and accrued liabilities approximate fair value due to the short-term nature of these instruments. To the extent the valuation of financial instruments is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. See Note 6, Fair value measurements for more information on how the Company determines fair value. Property and equipment, net Property and equipment are stated at cost, net of accumulated depreciation. Depreciation of property and equipment is computed using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Leasehold improvements are depreciated over the lesser of their useful lives or the remaining life of the lease. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is recorded in other income (expense), net in the period realized. Maintenance and repairs are expensed as incurred. Impairment of long-lived assets The Company reviews the carrying value and estimated lives of its long-lived assets whenever events or circumstances indicate the carrying values may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset’s carrying amount over its fair value. The Company has not recognized any impairment losses since inception. Acquisitions The Company accounts for business combinations using the acquisition method of accounting, which requires the assets acquired, including in-process research and development (IPR&D), and liabilities assumed be recorded at fair value as of the acquisition date. Any excess of the purchase price over the fair value of net assets acquired is recorded as goodwill. The determination of the estimated fair value of these items requires significant estimates and assumptions. Transaction costs associated with business combinations are recorded in general and administrative expense as they are incurred. If the Company determines the acquisition does not meet the definition of a business combination under the acquisition method of accounting, the transaction is accounted for as an asset acquisition. In an asset acquisition, up-front payments allocated to IPR&D are recorded in research and development expense if it is determined that there is no alternative future use, and subsequent milestone payments are recorded in research and development expense when achieved. Goodwill and intangible assets Goodwill represents the excess of the purchase price over the estimated fair value of the identifiable assets acquired and liabilities assumed in a business combination. The Company evaluates goodwill for impairment annually or when a triggering event occurs that could indicate a potential impairment. The evaluation for impairment includes assessing qualitative factors or performing a quantitative analysis to determine whether it is more-likely-than-not that the fair value of net assets is below the carrying amount. As of December 31, 2022, the Company had goodwill of $140.6 million related to its acquisition of Cobalt Biomedicine, Inc. (Cobalt) in 2019 (the Cobalt acquisition), which represents the excess of the purchase price over the estimated fair value of the net assets acquired. There have been no impairments of goodwill since the acquisition. Intangible assets acquired in a business combination are recognized separately from goodwill and are initially recognized at fair value at the acquisition date. The fair value of the IPR&D is estimated using the replacement cost method. Under this method, the Company estimates the cost to recreate the technology and derive an estimated value to develop the technology. IPR&D assets are required to be classified as indefinite-lived assets and are not amortized until they become finite-lived assets upon the successful completion of the associated research and development technology. At that time, the useful life of the asset will be determined, and amortization will begin. If the associated research and development technology is abandoned, the related IPR&D asset will be written off and an impairment charge recorded. Intangible assets are reviewed for impairment at least annually or when a triggering event occurs that could indicate a potential impairment. There has been no amortization or impairment of the intangible asset since the Cobalt acquisition. Contingent consideration from business combinations Contingent consideration from a business combination is recorded at fair value on the acquisition date and remeasured at each subsequent reporting period with changes in fair value recognized in research and development related success payments and contingent consideration. Changes in fair values reflect changes to the Company’s assumptions regarding probabilities of successful achievement of related milestones, the timing in which the milestones are expected to be achieved, and the discount rate used to estimate the fair value of the obligation. Pursuant to the terms and conditions of the Cobalt acquisition agreement, we are obligated to pay to certain former Cobalt stockholders contingent consideration (Cobalt Contingent Consideration). See Note 3, Acquisitions for more details on the Cobalt Consideration. Success payments The Company agreed to pay success payments to Cobalt (Cobalt Success Payment) pursuant to the terms of its acquisition agreement with Cobalt and to the President and Fellows of Harvard College (Harvard) (Harvard Success Payments) pursuant to the terms of its exclusive license agreement with Harvard. See Note 3, Acquisitions and Note 4, License and collaboration agreements for more details on these success payments. The success payments are accounted for under Accounting Standards Codification (ASC) 815, Derivatives and Hedging To determine the estimated fair value of the success payment liabilities, the Company uses a Monte Carlo simulation methodology , which models the value of the liabilities based on several key assumptions , including the remaining terms of the success payments, risk-free interest rate, estimated number and timing of valuation measurement dates on the basis of which payments may be triggered, and expected volatility of the Company’s common stock. Expected volatility is estimated using the volatility of peer companies for a period of time commensurate with the remaining terms of the success payments. Additionally, the computation of the estimated fair value of the Cobalt Success Payment liability incorporate s the market capitalization of the Company at the end of each reporting period , and the computation of the estimated fair value of the Harvard Success Payments incorporate s the per share fair market value of the Company’s common stock at the end of each reporting period. Leases At the inception of an arrangement with a third party, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Lease liabilities represent an obligation to make payments arising from a lease and are measured at the present value of the remaining future lease payments over the term of the lease. The present value of the lease payments is determined using an incremental borrowing rate (IBR), which reflects the fixed rate at which the Company could borrow the amount of the lease payments, on a collateralized basis, for a similar term and economic environment. The lease terms may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise the option. Assumptions made by the Company at the lease commencement date are re-evaluated upon the occurrence of certain events, including a lease modification. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease. Right-of-use (ROU) assets represent the right to use the underlying asset identified in the lease for the term of the agreement. The calculation of the ROU asset incorporates the value of the lease liability and excludes any lease incentives received and initial direct costs incurred. The Company’s lease portfolio consists of operating leases related to its facilities for office, laboratory, and industrial and manufacturing space. The Company does not have any financing leases. Leases with a term of 12 months or less are considered short-term and do not require recognition on the balance sheet, and payments associated with short-term leases are expensed as incurred. Rent expense for operating leases is recognized on a straight-line basis over the lease term. Claims and contingencies From time to time, the Company may become involved in litigation and proceedings relating to claims arising in the ordinary course of business. The Company accrues a liability if the likelihood of an adverse outcome is probable, and the amount can be reasonably estimated. If the likelihood of an adverse outcome is only reasonably possible, or if an adverse outcome is probable, but an estimate is not determinable, the Company provides disclosure of the material claim or contingency. Stock-based compensation The Company recognizes compensation costs related to restricted stock awards (RSAs), restricted stock units (RSUs), and stock options granted to employees and nonemployees based on the estimated fair value of the awards on the date of grant and recognizes expense on a straight-line basis over the requisite service period, which is generally the vesting period of the award. Forfeitures are recognized as they occur. For RSAs and RSUs, the fair value of the Company’s common stock is used to determine the resulting stock-based compensation expense. The fair value of stock options is estimated on the date of grant using a Black-Scholes option pricing model which requires management to apply judgment and make estimates, including: • Fair Value of Common Stock —The fair value of common stock is based on the closing price as reported on The Nasdaq Global Select Market on the date of grant. • Expected Term —The expected term represents the period that a stock-based award is expected to be outstanding. The Company uses the simplified method to determine the expected term, which is based on the average of the time-to-vesting and the contractual life of the option. • Expected Volatility — Due to the Company’s limited operating history and lack of company-specific historical and implied volatility data, the expected volatility is estimated based on the average historical volatilities of common stock of comparable publicly traded entities over a period of time commensurate with the expected term of the stock option grants. The comparable companies are chosen based on their size, stage in the product development cycle, or area of specialty. The Company will continue to apply this process until sufficient historical information regarding the volatility of its own stock price becomes available. • Risk-Free Interest Rate— The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the expected term of the awards. • Expected Dividend— The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero. Research and development expense The Company records expense for research and development costs as incurred. Nonrefundable, advance payments for goods or contracts for services are deferred, and expense is recognized in the period in which the goods are received or the services are rendered. Research and development expense consist of personnel-related costs, including salaries, benefits, and non-cash stock-based compensation, external research and development expenses incurred under arrangements with third parties, costs for laboratory supplies, costs to acquire and license technologies aligned with the Company’s goal of translating engineered cells to medicines, facility and other allocated expenses, including rent, depreciation, and allocated overhead costs. Research and development related success payment and contingent consideration Research and development related success payments and contingent consideration include the change in the estimated fair value of the Cobalt Success Payment and Harvard Success Payment liabilities and Cobalt Contingent Consideration. Research and development expense related to the success payment liabilities and contingent consideration is unpredictable and may vary significantly from quarter-to-quarter and year-to-year due to changes in the assumptions used in the calculations. General and administrative expenses General and administrative expenses consist of personnel costs, including salaries, benefits, and non-cash stock-based compensation, for employees in finance, legal, executive, human resources, information technology, and other administrative functions, legal and consulting fees, recruiting costs, and facility costs not otherwise included in research and development expenses. Legal fees include those related to corporate and patent matters. General and administrative expenses for the twelve months ended December 31, 2022 include costs related to the November 2022 restructuring and construction in progress costs incurred in connection with the write-off of our previously planned manufacturing facility in Fremont, California (Fremont facility), which we plan to replace with our manufacturing facility in Bothell, Washington (the Bothell facility). Income taxes The Company determines its deferred tax assets and liabilities based on the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that the deferred tax asset will not be recovered. The Company applies judgment in the determination of the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company recognizes any material interest and penalties related to unrecognized tax benefits in income tax expense. The Company is required to file income tax returns in the United States (U.S.) federal jurisdiction, and other state and local jurisdictions. The Company is generally subject to examination by U.S. federal and local income tax authorities for all tax years in which the loss carryforward is available. The Company is currently not under examination by the Internal Revenue Service or other jurisdictions for any tax years. Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. JOBS Act accounting election The Company is an emerging growth company (EGC), as defined in the Jumpstart Our Business Startups Act of 2012 (JOBS Act). Under the JOBS Act, an EGC can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies; however, the Company may adopt new or revised accounting standards early if the standard allows for early adoption. In addition, the Company will utilize other exemptions and reduced reporting requirements provided to EGCs by the JOBS Act. Subject to certain conditions set forth in the JOBS Act, an EGC is not required to, among other things, (i) provide an auditor’s attestation report on the company’s system of internal controls over financial reporting pursuant to Section 404(b) of the Sarbanes- Oxley Act of 2002, (ii) provide all of the compensation disclosure that may be required of non- EGC public companies under the Dodd-Frank Wall Street Reform and Consumer Protection Act, (iii) comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financial statements (auditor discussion and analysis) , or (iv) disclose certain executive compensation-related items , such as the correlation between executive compensation and performance and comparisons of the c hief e xecutive o fficer’s compensation to median employee compensation. Recent accounting pronouncements Recently adopted ASU No. 2017-04 , Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2022
Business Combinations [Abstract]
Acquisitions	3. Acquisitions Cobalt Biomedicine, Inc. In February 2019, the Company acquired 100% of the outstanding equity in Cobalt, a privately-held early-stage biotechnology company developing a platform technology using its fusogen technology to specifically and consistently deliver various biological payloads to cells (the Cobalt acquisition). As part of the Cobalt acquisition, the Company recorded an intangible asset of $59.2 million, which consists of IPR&D that is classified as indefinite-lived until the successful completion of the associated research and development technology, at which point it becomes a finite-lived asset and will be amortized over its estimated useful life. If the research and development technology is abandoned, an impairment charge will be recorded. The Company is actively developing the fusogen technology and, accordingly, the intangible asset is not complete. Amortization will begin when regulatory approval of a product candidate developed using the fusogen technology is obtained in a major market, typically either the United States or the European Union. The Company recognized $140.6 million of goodwill as a result of the Cobalt acquisition, which is primarily attributable to the value the acquisition provides the Company by complementing the Company’s ex vivo in vivo Pursuant to the terms and conditions in the Cobalt acquisition agreement, the Company has an obligation to pay to certain former Cobalt stockholders contingent consideration (Cobalt Contingent Consideration) of up to an aggregate of $500.0 million upon the achievement of certain pre-specified development milestones and a success payment (Cobalt Success Payment) of up to $500.0 million, each of which is payable in cash or stock. The Cobalt Success Payment is payable if, at pre-determined valuation measurement dates, the Company’s market capitalization equals or exceeds $8.1 billion, and the Company is advancing a program based on the fusogen technology in a clinical trial pursuant to an investigational new drug application (IND), or has filed for, or received approval for, a biologics license application (BLA) or new drug application (NDA) for a product developed using the fusogen technology. A valuation measurement date would also be triggered upon a change of control of the Company if at least one of the Company’s programs based on the fusogen technology is an active research program at the time of such change of control. If the Company’s market capitalization is below $8.1 billion as of the date of a change of control, the amount of the potential Cobalt Success Payment will decrease, and the amount of potential Cobalt Contingent Consideration will increase. As of December 31 , 202 2 , a Cobalt Success Payment had not been triggered. The following table sets forth various thresholds for the Company’s market capitalizations as of the date of a change of control and the resulting potential Cobalt Success Payment and additional potential Cobalt Contingent Consideration: Sana market capitalization upon a change of control and resulting impact to Cobalt Success Payment and additional potential Cobalt Contingent Consideration Cobalt Success Payment Additional potential Cobalt Contingent Consideration (in millions) Equal to or exceeds $8.1 billion $ 500 $ - Equal to or exceeds $7.4 billion, but less than $8.1 billion 150 350 Equal to or exceeds $6.8 billion, but less than $7.4 billion 100 400 Less than $6.8 billion - 500 The Cobalt Success Payment and Cobalt Contingent Consideration liabilities are carried at fair value with changes in fair value recognized in research and development related success payments and contingent consideration. As of December 31, 2022 and 2021, the estimated fair value of the Cobalt Success Payment liability was $19.0 million and $88.3 million, respectively, and was recorded in long-term liabilities. For the years ended December 31, 2022, 2021, and 2020 the Company recognized a gain of $69.3 million and expenses of $23.6 million and $62.3 million, respectively, As of December 31, 2022, the estimated fair value of the Cobalt Contingent Consideration was $150.4 million, of which $55.4 million was recorded in short-term liabilities and $95.0 million was recorded in long-term liabilities. As of December 31, 2021, the estimated fair value of the Cobalt Contingent Consideration was $153.7 million of which $51.4 million was recorded in short-term liabilities and $102.3 million was recorded in long-term liabilities. For the years ended December 31, 2022, 2021, and 2020, the Company recognized a gain of $3.4 million and expenses of $31.8 million and $52.8 million, respectively, in connection with the change in fair value of the Cobalt Contingent Consideration.

License and collaboration agree

License and collaboration agreements	12 Months Ended
	Dec. 31, 2022
License And Collaboration Agreements [Abstract]
License and Collaboration Agreements	4. License and collaboration agreements Beam Therapeutics Inc. In October 2021, the Company entered into an option and license agreement with Beam Therapeutics Inc. (Beam), pursuant to which the Company was granted a non-exclusive license to use Beam’s proprietary CRISPR Cas12b nuclease editing technology to research, develop, and commercialize engineered cell therapy products that (i) are directed to certain antigen targets, with respect to the Company’s allogeneic T cell programs, or (ii) comprise certain human cell types, with respect to the Company’s stem cell-derived programs. The Company made an upfront payment of $50.0 million to Beam, which was recorded in research and development expense for the year ended December 31, 2021. Additionally, under the terms of the agreement, the Company may be obligated to pay up to $65.0 million for each licensed product in specified developmental and commercial milestone payments and royalties on licensed products. At the time of the entry into the option and license agreement, a member of the Company’s board of directors was a beneficial owner of greater than 10% of the outstanding shares of Beam and is affiliated with a member of the board of directors of Beam. President and Fellows of Harvard College In March 2019, the Company entered into an exclusive license agreement with Harvard to access certain intellectual property for the development of hypoimmune cells. The Company paid aggregate consideration of $12.0 million, comprising $9.0 million in common stock and $3.0 million in cash. Under the terms of the agreement, the Company may be required to make up to an aggregate of $175.0 million in success payments to Harvard, payable in cash, based on increases in the fair value of the Company’s common stock. The potential Harvard Success Payments are based on multiples of increased value ranging from 5x to 40x, based on a comparison of the fair market value of the Company’s common stock relative to the original issuance price of $4.00 per share at ongoing pre-determined valuation measurement dates. As of December 31, 2022, a Harvard Success Payment had not been triggered. Multiple of Equity Value at Issuance 5x 10x 20x 30x 40x Per share common stock price required for payment $ 20.00 $ 40.00 $ 80.00 $ 120.00 $ 160.00 Success payment(s) (in millions) $ 5.0 $ 15.0 $ 30.0 $ 50.0 $ 75.0 The Harvard Success Payment liabilities are carried at fair value, with the initial value and changes in fair value recognized in the consolidated statements of operations in research and development related success payments and contingent consideration. As of December 31, 2022 the estimated fair value of the Harvard Success Payment liability was $2.0 million and was recorded in long-term liabilities. As of December 31, 2021 the estimated fair value of the Harvard Success Payment liability was $14.2 million, of which $5.0 million was recorded in short-term liabilities and $9.2 million was recorded in long-term liabilities. In connection with the change in the estimated fair value of the Harvard Success Payment liability the Company recognized a gain of $12.2 million, and expenses of $2.4 million, and $9.9 million, respectively, for the years ended December 31, 2022, 2021, and 2020.

Restricted Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2022
Restricted Cash And Cash Equivalents [Abstract]
Restricted Cash	5. Restricted cash As of December 31, 2022 and 2021, the Company maintained two standby letters of credit of $10.5 million and $8.8 million, respectively, which are collateralized with a bank account at a financial institution in accordance with the applicable lease agreements. The Company’s letter of credit related to its lease for industrial space located in Fremont, California will reduce from $6.7 million to $0.6 million in July 2023, and as such, $6.1 million in restricted cash is included in current assets on the balance sheet as of December 31, 2022.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair value measurements The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis based on the three-tier fair value hierarchy: December 31, 2022 Valuation Hierarchy Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Estimated Fair Value (in thousands) Financial assets: Cash equivalents: Money market funds Level 1 $ 114,363 $ - $ - $ 114,363 U.S. government and agency securities Level 2 40,532 10 - 40,542 Corporate debt securities Level 2 9,796 1 (2 ) 9,795 Total cash equivalents 164,691 11 (2 ) 164,700 Short-term marketable securities: U.S. government and agency securities Level 2 222,435 2 (3,711 ) 218,726 Corporate debt securities Level 2 28,836 - (364 ) 28,472 Total short-term marketable securities 251,271 2 (4,075 ) 247,198 Long-term marketable securities: U.S. government and agency securities Level 2 10,314 - (263 ) 10,051 Total long-term marketable securities 10,314 - (263 ) 10,051 Other assets Level 3 369 - - 369 Total financial assets $ 426,645 $ 13 $ (4,340 ) $ 422,318 Financial liabilities: Short-term financial liabilities: $ - Contingent consideration Level 3 $ 55,345 $ - $ - $ 55,345 Total short-term financial liabilities 55,345 - - 55,345 Long-term financial liabilities: Contingent consideration Level 3 95,034 - - 95,034 Success payment liabilities Level 3 21,007 - - 21,007 Total long-term financial liabilities 116,041 - - 116,041 Total financial liabilities $ 171,386 $ - $ - $ 171,386 December 31, 2021 Valuation Hierarchy Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Estimated Fair Value (in thousands) Financial assets: Cash equivalents: Money market funds Level 1 $ 224,671 $ - $ - $ 224,671 Corporate debt securities Level 2 2,345 - - 2,345 Total cash equivalents 227,016 - - 227,016 Short-term marketable securities: U.S. government and agency securities Level 2 162,854 1 (195 ) 162,660 Corporate debt securities Level 2 135,441 - (134 ) 135,307 Total short-term marketable securities 298,295 1 (329 ) 297,967 Long-term marketable securities: U.S. government and agency securities Level 2 176,492 - (925 ) 175,567 Corporate debt securities Level 2 20,427 - (113 ) 20,314 Total long-term marketable securities 196,919 - (1,038 ) 195,881 Other assets Level 3 426 - - 426 Total financial assets $ 722,656 $ 1 $ (1,367 ) $ 721,290 Financial liabilities: Short-term financial liabilities: Contingent consideration Level 3 $ 51,382 $ - $ - $ 51,382 Success payment liabilities Level 3 5,000 - - 5,000 Total short-term financial liabilities 56,382 - - 56,382 Long-term financial liabilities: Contingent consideration Level 3 102,361 - - 102,361 Success payment liabilities Level 3 97,525 - - 97,525 Total long-term financial liabilities 199,886 - - 199,886 Total financial liabilities $ 256,268 $ - $ - $ 256,268 The Company measures the fair value of money market funds based on quoted prices in active markets for identical assets or liabilities. The Level 2 marketable securities include U.S. government and agency securities and corporate debt securities and are valued based on either recent trades of securities in inactive markets or quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. The following table summarizes available-for-sale debt securities in a continuous unrealized loss position for less than and greater than twelve months, for the periods presented: Less than 12 months 12 months or greater Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses (in thousands) December 31, 2022 U.S. government and agency securities $ 49,253 $ (673 ) $ 172,845 $ (3,301 ) $ 222,098 $ (3,974 ) Corporate debt securities 13,333 (16 ) 19,664 (350 ) 32,997 (366 ) Total $ 62,586 $ (689 ) $ 192,509 $ (3,651 ) $ 255,095 $ (4,340 ) December 31, 2021 U.S. government and agency securities $ 329,883 $ (1,120 ) $ - $ - $ 329,883 $ (1,120 ) Corporate debt securities 156,662 (247 ) - - 156,662 (247 ) Total $ 486,545 $ (1,367 ) $ - $ - $ 486,545 $ (1,367 ) The Company determined that there was no material change in the credit risk of the above investments during the year ended December 31, 2022. As such, an allowance for credit losses has not been recognized. As of December 31, 2022, the Company does not intend to sell such securities, and it is not more-likely-than-not that the Company will be required to sell the securities prior to the recovery of the amortized cost basis. As of December 31, 2021, all marketable securities had an effective maturity date of two years or less. Investments in securities with maturities of less than , or those for which management intends to use to fund current operations, are included in current assets and classified as available-for-sale. The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities: Contingent Consideration Cobalt Success Payment Liability Harvard Success Payment Liability (in thousands) Balance as of December 31, 2021 $ 153,743 $ 88,353 $ 14,172 Changes in fair value - gain (528 ) (46,823 ) (8,087 ) Balance as of March 31, 2022 153,215 41,530 6,085 Changes in fair value - gain (3,830 ) (12,073 ) (2,025 ) Balance as of June 30, 2022 149,385 29,457 4,060 Changes in fair value - expense (gain) (8,255 ) 2,439 (246 ) Balance as of September 30, 2022 141,130 31,896 3,814 Changes in fair value - expense (gain) 9,249 (12,880 ) (1,823 ) Balance as of December 31, 2022 $ 150,379 $ 19,016 $ 1,991 Contingent consideration The Company utilizes significant estimates and assumptions it believes would be made by a market participant in determining the estimated fair value of the Cobalt Contingent Consideration at each balance sheet date. The fair value of the Cobalt Contingent Consideration was determined by calculating the probability-weighted estimated value of the pre-specified development milestone payments based on the assessment of the likelihood and estimated timing that the milestones would be achieved and the applicable discount rates. The discount rate captures the credit risk associated with the payment of the contingent consideration when earned and due. The Company assesses these estimates on an ongoing basis as additional data impacting the assumptions are obtained. The fair value of the Cobalt Contingent Consideration was calculated using the following unobservable inputs: December 31, 2022 2021 Unobservable Input Range Weighted-Average Range Weighted-Average Discount rates 13.4% - 15.1% 14.6% 10.9% - 11.6% 11.2% Probability of milestone achievement 5.0% - 85.0% 36.0% 5.0% - 75.0% 33.8% The weighted-average unobservable inputs were calculated based on the relative value of the pre-specified development milestones. The estimated fair value of the Cobalt Contingent Consideration may change significantly as development progresses and additional data are obtained, impacting the assumptions regarding probabilities of successful achievement of the milestones used to estimate the fair value of the liability and the timing in which they are expected to be achieved. In evaluating the fair value assumptions, judgment is required to interpret the market data used to develop the estimates. The estimates of fair value may not be indicative of the amounts that could be realized in a current market exchange. Accordingly, the use of different market assumptions, inputs, and/or different valuation techniques could result in materially different fair value estimates. Success payments The Company utilizes significant estimates and assumptions in determining the estimated fair value of the success payment liabilities and the associated expense or gain at each balance sheet date. The estimated fair value of the Cobalt Success Payment and Harvard Success Payment liabilities was determined using a Monte Carlo simulation methodology, which models the estimated fair value of the liability based on several key assumptions, including the expected volatility, remaining term, risk-free interest rate, estimated number and timing of valuation measurement dates on the basis of which payment may be triggered, and for the Cobalt Success Payment, the Company’s market capitalization, and for the Harvard Success Payments, the per share fair value of the Company’s common stock. The fair values of the Cobalt Success Payments and Harvard success Payments were calculated using the following unobservable inputs: December 31, 2022 2021 Unobservable Input Cobalt Harvard Cobalt Harvard Expected stock price volatility 70% 70% 70% 70% Expected term (years) 16.1 8.2 17.1 9.2

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2022
Property Plant And Equipment [Abstract]
Property and Equipment, Net	7. Property and equipment, net Property and equipment, net consists of the following: December 31, 2022 2021 (in thousands) Laboratory equipment $ 61,842 $ 47,684 Leasehold improvements 34,427 33,848 Construction in progress 1,711 1,388 Computer equipment, software, and other 2,914 1,318 Total property and equipment, at cost 100,894 84,238 Less: Accumulated depreciation (33,977 ) (18,774 ) Property and equipment, net $ 66,917 $ 65,464 Depreciation expense was $15.6 million, $11.1 million, and $5.9 million for the years ended December 31, 2022, 2021, and 2020, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2022
Payables And Accruals [Abstract]
Accrued liabilities	8. Accrued liabilities Accrued compensation and accrued expenses and other current liabilities consist of the following: December 31, 2022 2021 (in thousands) Accrued compensation: Accrued bonuses $ 16,455 $ 13,814 Accrued paid time off 4,794 4,429 Accrued payroll 5,113 2,888 Total accrued compensation $ 26,362 $ 21,131 Accrued expenses and other current liabilities: Accrued research and development services $ 8,733 $ 3,419 Accrued professional fees 1,158 1,971 Accrued property and equipment 1,790 2,566 Other accrued current liabilities 2,866 2,388 Total accrued expenses and other current liabilities $ 14,547 $ 10,344

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and contingencies Lease commitments The Company’s lease portfolio primarily comprises operating leases for office, laboratory, non-good manufacturing practices pilot plant manufacturing, and industrial space. These leases contain various rent abatement periods, after which they require monthly lease payments that may be subject to annual increases throughout the lease term. Certain leases include options to extend the term. The renewal option is considered in the remaining lease term for the lease only when the Company is reasonably certain it will renew the lease. Certain leases provide the Company with the right to make tenant improvements, including the addition of laboratory space or build-out of manufacturing capabilities, and include a lease incentive allowance. In June 2022, the Company entered into a lease agreement for 79,565 square feet of office, laboratory, and industrial space located in Bothell, Washington. The initial term of the lease is 16 years from the date the premises are delivered to the Company for construction of certain tenant improvements and includes the option to extend the lease for up to three additional five-year terms. The lease agreement also provides for up to $19.9 million for reimbursement of tenant improvements, as well as an additional $8.0 million for tenant improvements, available at the Company’s election, which the Company would be obligated to repay to the landlord monthly over the initial term of the lease with interest at a rate of 6.5% per annum. In July 2021, the Company entered into a lease for industrial space located in Fremont, California (the Fremont facility), with the intent to establish and develop its manufacturing operations at the Fremont facility. However, the Company determined in June 2022 to establish and develop its manufacturing operations at the Bothell facility rather than the Fremont facility. The original right-of-use asset and lease liability for the Fremont facility was calculated assuming the Company would exercise its option to renew the lease for two additional five-year terms. The Company remeasured the lease for the Fremont facility due to the shorter expected lease term, which resulted in a $12.8 million reduction in the related right-of-use asset and lease liability. Additionally, for the twelve months ended December 30, 2022, the Company wrote-off $4.5 million of construction in progress costs incurred in connection with the Fremont facility in general and administrative expense. The following table contains additional information related to the Company’s operating leases: Location Use Approximate Square Footage Commencement Dates Expiration Dates Seattle, WA Office/Laboratory 48,000 March 2019 to September 2020 December 2026 to April 2028 Cambridge, MA Office/Laboratory 60,000 March 2019 to January 2022 December 2025 to February 2028 South San Francisco, CA Office/Laboratory 100,000 December 2019 to April 2022 April 2024 to April 2030 Fremont, CA Industrial 163,000 July 2021 November 2031 Rochester, NY Office/Laboratory 3,000 January 2022 January 2025 Bothell, WA Office/Laboratory/Industrial 80,000 January 2023 January 2039 Throughout the term of the lease agreements, the Company is responsible for paying certain operating costs in addition to rent, such as common area maintenance, taxes, utilities, and insurance. These additional charges are considered variable lease costs and are recognized in the period in which the costs are incurred. The following table summarizes the Company’s lease costs: Year Ended December 31, 2022 2021 2020 (in thousands) Operating lease cost $ 23,881 $ 16,425 $ 10,757 Short-term lease cost - 512 1,886 Variable lease cost 7,193 5,230 3,081 Total lease cost $ 31,074 $ 22,167 $ 15,724 As of December 31, 2022, the weighted-average remaining lease term was 6.2 years and the weighted-average IBR was 9.68%. The following table reconciles the Company’s undiscounted operating lease cash flows by fiscal year to the present value of the operating lease liabilities as of December 31, 2022 (in thousands): 2023 $ 23,523 2024 24,321 2025 24,298 2026 21,343 2027 18,736 2028 and thereafter 36,367 Total undiscounted lease payments 148,588 Less: imputed interest (39,018 ) Less: tenant improvement allowances (1,317 ) Present value of operating lease liabilities 108,253 Less: current portion of operating lease liabilities (12,393 ) Operating lease liabilities, net of current portion $ 95,860

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ equity As of December 31, 2022, there were 191.0 million shares of the Company’s common stock outstanding. As of December 31, 2021, there were 184.9 million shares of the Company’s common stock outstanding, excluding 4.4 million shares of restricted common stock outstanding that are subject to vesting requirements. In August 2022, the Company put in place the ATM facility, under which the Company entered a sales agreement with Cowen, acting as sales agent, pursuant to which the Company may offer and sell through Cowen shares of the Company’s common stock having an aggregate offering price of up to $150.0 million from time to time in a series of one or more at the market equity offerings. As of December 31, 2022, the Company had raised approximately $0.6 million in net proceeds under the ATM facility.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation	11. Stock-based compensation Equity Incentive Plans In February 2021, the Company adopted the 2021 Incentive Award Plan (2021 Plan) and the 2021 Employee Stock Purchase Plan (2021 ESPP), both of which became effective on the completion of the Company’s IPO. The 2021 Plan provides for a variety of stock-based compensation awards, including stock options, restricted stock awards (RSAs), and restricted stock units (RSUs). The 2021 ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their earnings, subject to plan limitations. Unless otherwise determined by the Company’s board of directors, employees may purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first date of an offering period or on the purchase date. As of December 31, 2022, 14.4 million shares and 3.3 million shares were available for future issuance under the 2021 Plan and the 2021 ESPP, respectively. Stock-based compensation expense Stock-based compensation expense is recognized in the consolidated statements of operations as follows: Year Ended December 31, 2022 2021 2020 (in thousands) Research and development $ 26,583 $ 15,239 $ 4,888 General and administrative (1) 11,754 7,123 940 Total stock-based compensation expense $ 38,337 $ 22,362 $ 5,828 (1) Unrecognized stock-based compensation costs related to unvested awards and the weighted-average period over which the costs are expected to be recognized as of December 31, 2022 are as follows: Stock Options RSAs RSUs Unrecognized stock-based compensation expense (in thousands) $ 73,291 $ 13 $ 4,209 Weighted-average period costs expected to be recognized (in years) 2.7 0.3 2.2 Stock options A summary of the Company’s stock option activity is as follows: Stock Options (in thousands) Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2021 17,337 $ 8.96 8.7 $ 141,718 Granted 11,949 6.09 Exercised (1,062 ) 2.10 Forfeited/Cancelled (4,538 ) 9.12 Outstanding as of December 31, 2022 23,686 $ 7.79 8.3 $ 10,628 Exercisable as of December 31, 2022 7,402 $ 7.32 7.3 $ 7,648 The fair value of stock options granted to employees, directors, and consultants was estimated on the date of grant using the Black-Scholes option pricing model using the following assumptions: Assumptions 2022 2021 2020 Risk free interest rate 1.56% - 4.31% 0.46% - 1.38% 0.36% - 1.51% Expected volatility 70% 70% 70% Expected term (years) 5.50 - 6.25 5.50 - 6.40 6.25 - 6.75 Expected dividend 0% 0% 0% The following table summarizes additional information related to stock option activity: 2022 2021 2020 Weighted average grant date fair value per share for options granted $ 3.92 $ 14.22 $ 3.52 Aggregate intrinsic value of stock options exercised (in thousands) $ 6,133 $ 29,880 $ 605 Restricted stock A summary of the Company’s RSA and RSU activity is as follows: RSAs (in thousands) RSAs Weighted-Average Grant Date Fair Value per Share RSUs (in thousands) RSUs Weighted-Average Grant Date Fair Value per Share Unvested shares as of December 31, 2021 4,365 $ 0.43 141 $ 9.43 Granted - - 1,075 6.21 Vested (4,309 ) 0.42 (86 ) 9.52 Forfeited (44 ) 0.94 (245 ) 5.38 Unvested shares as of December 31, 2022 12 $ 1.44 885 $ 6.66 The fair value of vested RSAs was $1.8 million, $1.5 million, and $1.5 million, respectively, for the years ended December 31, 2022, 2021, and 2020. The fair value of vested RSUs was $0.5 million and $4.1 million for the years ended December 31, 2022 and 2021, and immaterial for the year ended December 31, 2020.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	12. Income taxes As of December 31, 2022, the Company had U.S. federal and state tax-effected net operating loss (NOL) carryforwards of $120.2 million and $34.6 million, respectively, which are available to reduce future taxable income. As of December 31, 2022, the Company also had federal and state research tax credits of $30.8 million and $13.3 million, respectively, which may be used to offset future liabilities. The Tax Cuts and Jobs Act enacted on December 22, 2017 altered the carryforward period for federal net operating losses and as a result, all net operating losses generated in 2018 and forward have an indefinite life. Of the federal net operating losses reported, we have accumulated $118.6 million with an indefinite life as of December 31, 2022. The state NOL will begin to expire in 2036. The federal tax credit carryforward will begin to expire in 2037, and the state tax credit will carry forward indefinitely. The NOL and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. Subsequent ownership changes may further affect the limitation in future years. A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows: Year Ended December 31, 2022 2021 2020 Federal statutory tax 21.00 % 21.00 % 21.00 % State income tax, net of federal benefit 13.49 2.75 2.09 Valuation allowance (43.69 ) (24.06 ) (15.18 ) Success payment liabilities 5.40 (1.40 ) (4.58 ) Contingent consideration 0.26 (1.88 ) (3.89 ) Tax credits 4.93 2.58 1.88 Other (1.39 ) 1.01 (1.32 ) Effective income tax rate 0.00 % 0.00 % 0.00 % The principal components of the Company’s net deferred tax assets are as follows: December 31, 2022 2021 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 154,888 $ 114,368 Capitalized research and development 49,687 - Tax credit carryforwards 44,051 24,008 Lease liabilities 28,050 25,754 Intangibles 7,949 5,986 Stock-based compensation 6,958 1,854 Accrued liabilities and allowances 6,807 4,401 Success payment liabilities 516 3,290 Other 155 - Gross deferred tax assets 299,061 179,661 Valuation allowance (274,348 ) (156,622 ) Deferred tax assets, net of valuation allowance 24,713 23,039 Deferred tax liabilities: Right-of-use assets (23,554 ) (21,940 ) Fixed assets (1,159 ) (1,050 ) Other - (49 ) Deferred tax liabilities (24,713 ) (23,039 ) Net deferred taxes assets $ - $ - The Tax Cuts and Jobs Act contained a provision which requires the capitalization of Section 174 costs incurred in years beginning on or after January 1, 2022. Section 174 costs are expenditures which represent research and development costs that are incident to the development or improvement of a product, process, formula, invention, computer software, or technique. This provision changes the treatment of Section 174 costs such that the expenditures are no longer allowed as an immediate deduction but rather must be capitalized and amortized. The valuation allowance relates primarily to net U.S. deferred tax assets from operating losses, research tax credit carryforwards, capitalized research and development, and amounts paid and accrued to enter into various agreements for which the tax treatment requires capitalization and amortization. The Company maintains a full valuation allowance on its net U.S. deferred tax assets. The assessment regarding whether a valuation allowance is required considers both positive and negative evidence when determining whether it is more likely than not that deferred tax assets are recoverable. In making this assessment, significant weight is given to evidence that can be objectively verified. In its evaluation, the Company considered its cumulative losses and its forecasted losses in the near term as significant negative evidence. Based upon a review of the four sources of income identified within ASC 740, Accounting for Income Taxes The Company determines its uncertain tax positions based on a determination of whether and how much of the tax benefit the Company takes in its tax filings or positions is more likely than not to be sustained upon examination by the relevant income tax authorities. The Company is generally subject to examination by U.S. federal and local income tax authorities for all tax years in which the loss carryforward is available. The Company applies judgment in its determination of the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. As of December 31, 2022 and 2021, the Company’s uncertain tax positions were immaterial.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	13. Net loss per share Basic and diluted net loss per common share are calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. The Company was in a loss position for all periods presented, and basic net loss per share and diluted net loss per share are therefore the same for all periods, as the inclusion of all potential common securities outstanding would have been anti-dilutive. The following securities were excluded from the computation of net loss per diluted share of common stock for periods presented as their effect would have been anti-dilutive: Year Ended December 31, 2022 2021 2020 (in thousands) Convertible preferred stock - - 134,113 Options to purchase common stock 23,686 17,337 15,677 Unvested restricted common stock 12 4,365 10,079 Unvested RSUs 885 141 326 Total 24,583 21,843 160,195

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2022
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	14. Employee benefit plan In January 2019, the Company adopted a 401(k) retirement and savings plan (the 401(k) Plan) covering all employees. The 401(k) Plan allows employees to make pre- and post-tax contributions up to the maximum allowable amount set by the IRS. Effective as of January 1, 2022, the Company began matching each participant’s 401(k) contributions, up to $4,000 per year per participant.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (GAAP). Certain prior period amounts have been reclassified to conform to current period presentation.
Use of estimates	Use of estimates The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates. The most significant estimates in the Company’s consolidated financial statements relate to success payment liabilities, contingent consideration, business combinations, accrued expenses, and operating lease right of use assets and liabilities.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents include cash and highly liquid investments with original maturities of three months or less at acquisition. Cash equivalents include investments in money market funds with commercial banks and financial institutions and are stated at fair value.
Marketable securities	Marketable securities Marketable securities are classified as available-for-sale debt securities and are carried at fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities. Investments in securities with maturities of less than one year, or those for which management intends to use to fund current operations, are included in current assets. Unrealized gains and losses that are deemed to be temporary in nature are reported as a component of accumulated comprehensive income (loss). Amortization, accretion, and dividends are included in other income (expense), net on the consolidated statement of operations. The cost of securities sold is based on the specific-identification method. Each reporting period, the Company evaluates whether declines in fair value below carrying value are due to expected credit losses, as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs. Expected credit losses are recorded as an allowance through other income (expense), net.
Concentrations of credit risk and off-balance sheet risk	Concentrations of credit risk and off-balance sheet risk The Company maintains its cash, cash equivalents, and marketable securities with high quality, accredited financial institutions. These amounts, at times, may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to significant risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements.
Fair value measurement	Fair value measurement The Company accounts for certain assets and liabilities at fair value and is required to disclose information that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The hierarchy applies only to the valuation inputs used to determine the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. The Company’s financial instruments include cash and cash equivalents, short- and long-term marketable securities, accounts payable, contingent consideration, success payment liabilities, and other accrued liabilities. The carrying amounts of cash, cash equivalents, accounts payable, and accrued liabilities approximate fair value due to the short-term nature of these instruments. To the extent the valuation of financial instruments is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. See Note 6, Fair value measurements for more information on how the Company determines fair value.
Property and equipment, net	Property and equipment, net Property and equipment are stated at cost, net of accumulated depreciation. Depreciation of property and equipment is computed using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Leasehold improvements are depreciated over the lesser of their useful lives or the remaining life of the lease. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is recorded in other income (expense), net in the period realized. Maintenance and repairs are expensed as incurred.
Impairment of long-lived assets	Impairment of long-lived assets The Company reviews the carrying value and estimated lives of its long-lived assets whenever events or circumstances indicate the carrying values may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset’s carrying amount over its fair value. The Company has not recognized any impairment losses since inception.
Acquisitions	Acquisitions The Company accounts for business combinations using the acquisition method of accounting, which requires the assets acquired, including in-process research and development (IPR&D), and liabilities assumed be recorded at fair value as of the acquisition date. Any excess of the purchase price over the fair value of net assets acquired is recorded as goodwill. The determination of the estimated fair value of these items requires significant estimates and assumptions. Transaction costs associated with business combinations are recorded in general and administrative expense as they are incurred. If the Company determines the acquisition does not meet the definition of a business combination under the acquisition method of accounting, the transaction is accounted for as an asset acquisition. In an asset acquisition, up-front payments allocated to IPR&D are recorded in research and development expense if it is determined that there is no alternative future use, and subsequent milestone payments are recorded in research and development expense when achieved.
Goodwill and intangible assets	Goodwill and intangible assets Goodwill represents the excess of the purchase price over the estimated fair value of the identifiable assets acquired and liabilities assumed in a business combination. The Company evaluates goodwill for impairment annually or when a triggering event occurs that could indicate a potential impairment. The evaluation for impairment includes assessing qualitative factors or performing a quantitative analysis to determine whether it is more-likely-than-not that the fair value of net assets is below the carrying amount. As of December 31, 2022, the Company had goodwill of $140.6 million related to its acquisition of Cobalt Biomedicine, Inc. (Cobalt) in 2019 (the Cobalt acquisition), which represents the excess of the purchase price over the estimated fair value of the net assets acquired. There have been no impairments of goodwill since the acquisition. Intangible assets acquired in a business combination are recognized separately from goodwill and are initially recognized at fair value at the acquisition date. The fair value of the IPR&D is estimated using the replacement cost method. Under this method, the Company estimates the cost to recreate the technology and derive an estimated value to develop the technology. IPR&D assets are required to be classified as indefinite-lived assets and are not amortized until they become finite-lived assets upon the successful completion of the associated research and development technology. At that time, the useful life of the asset will be determined, and amortization will begin. If the associated research and development technology is abandoned, the related IPR&D asset will be written off and an impairment charge recorded. Intangible assets are reviewed for impairment at least annually or when a triggering event occurs that could indicate a potential impairment. There has been no amortization or impairment of the intangible asset since the Cobalt acquisition.
Contingent consideration from business combinations	Contingent consideration from business combinations Contingent consideration from a business combination is recorded at fair value on the acquisition date and remeasured at each subsequent reporting period with changes in fair value recognized in research and development related success payments and contingent consideration. Changes in fair values reflect changes to the Company’s assumptions regarding probabilities of successful achievement of related milestones, the timing in which the milestones are expected to be achieved, and the discount rate used to estimate the fair value of the obligation. Pursuant to the terms and conditions of the Cobalt acquisition agreement, we are obligated to pay to certain former Cobalt stockholders contingent consideration (Cobalt Contingent Consideration). See Note 3, Acquisitions for more details on the Cobalt Consideration.
Success payments	Success payments The Company agreed to pay success payments to Cobalt (Cobalt Success Payment) pursuant to the terms of its acquisition agreement with Cobalt and to the President and Fellows of Harvard College (Harvard) (Harvard Success Payments) pursuant to the terms of its exclusive license agreement with Harvard. See Note 3, Acquisitions and Note 4, License and collaboration agreements for more details on these success payments. The success payments are accounted for under Accounting Standards Codification (ASC) 815, Derivatives and Hedging To determine the estimated fair value of the success payment liabilities, the Company uses a Monte Carlo simulation methodology , which models the value of the liabilities based on several key assumptions , including the remaining terms of the success payments, risk-free interest rate, estimated number and timing of valuation measurement dates on the basis of which payments may be triggered, and expected volatility of the Company’s common stock. Expected volatility is estimated using the volatility of peer companies for a period of time commensurate with the remaining terms of the success payments. Additionally, the computation of the estimated fair value of the Cobalt Success Payment liability incorporate s the market capitalization of the Company at the end of each reporting period , and the computation of the estimated fair value of the Harvard Success Payments incorporate s the per share fair market value of the Company’s common stock at the end of each reporting period.
Leases	Leases At the inception of an arrangement with a third party, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Lease liabilities represent an obligation to make payments arising from a lease and are measured at the present value of the remaining future lease payments over the term of the lease. The present value of the lease payments is determined using an incremental borrowing rate (IBR), which reflects the fixed rate at which the Company could borrow the amount of the lease payments, on a collateralized basis, for a similar term and economic environment. The lease terms may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise the option. Assumptions made by the Company at the lease commencement date are re-evaluated upon the occurrence of certain events, including a lease modification. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease. Right-of-use (ROU) assets represent the right to use the underlying asset identified in the lease for the term of the agreement. The calculation of the ROU asset incorporates the value of the lease liability and excludes any lease incentives received and initial direct costs incurred. The Company’s lease portfolio consists of operating leases related to its facilities for office, laboratory, and industrial and manufacturing space. The Company does not have any financing leases. Leases with a term of 12 months or less are considered short-term and do not require recognition on the balance sheet, and payments associated with short-term leases are expensed as incurred. Rent expense for operating leases is recognized on a straight-line basis over the lease term.
Claims and contingencies	Claims and contingencies From time to time, the Company may become involved in litigation and proceedings relating to claims arising in the ordinary course of business. The Company accrues a liability if the likelihood of an adverse outcome is probable, and the amount can be reasonably estimated. If the likelihood of an adverse outcome is only reasonably possible, or if an adverse outcome is probable, but an estimate is not determinable, the Company provides disclosure of the material claim or contingency.
Stock-based compensation	Stock-based compensation The Company recognizes compensation costs related to restricted stock awards (RSAs), restricted stock units (RSUs), and stock options granted to employees and nonemployees based on the estimated fair value of the awards on the date of grant and recognizes expense on a straight-line basis over the requisite service period, which is generally the vesting period of the award. Forfeitures are recognized as they occur. For RSAs and RSUs, the fair value of the Company’s common stock is used to determine the resulting stock-based compensation expense. The fair value of stock options is estimated on the date of grant using a Black-Scholes option pricing model which requires management to apply judgment and make estimates, including: • Fair Value of Common Stock —The fair value of common stock is based on the closing price as reported on The Nasdaq Global Select Market on the date of grant. • Expected Term —The expected term represents the period that a stock-based award is expected to be outstanding. The Company uses the simplified method to determine the expected term, which is based on the average of the time-to-vesting and the contractual life of the option. • Expected Volatility — Due to the Company’s limited operating history and lack of company-specific historical and implied volatility data, the expected volatility is estimated based on the average historical volatilities of common stock of comparable publicly traded entities over a period of time commensurate with the expected term of the stock option grants. The comparable companies are chosen based on their size, stage in the product development cycle, or area of specialty. The Company will continue to apply this process until sufficient historical information regarding the volatility of its own stock price becomes available. • Risk-Free Interest Rate— The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of grant for zero-coupon U.S. Treasury notes with maturities approximately equal to the expected term of the awards. • Expected Dividend— The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.
Research and development expense	Research and development expense The Company records expense for research and development costs as incurred. Nonrefundable, advance payments for goods or contracts for services are deferred, and expense is recognized in the period in which the goods are received or the services are rendered. Research and development expense consist of personnel-related costs, including salaries, benefits, and non-cash stock-based compensation, external research and development expenses incurred under arrangements with third parties, costs for laboratory supplies, costs to acquire and license technologies aligned with the Company’s goal of translating engineered cells to medicines, facility and other allocated expenses, including rent, depreciation, and allocated overhead costs.
Research and development related success payment and contingent consideration	Research and development related success payment and contingent consideration Research and development related success payments and contingent consideration include the change in the estimated fair value of the Cobalt Success Payment and Harvard Success Payment liabilities and Cobalt Contingent Consideration. Research and development expense related to the success payment liabilities and contingent consideration is unpredictable and may vary significantly from quarter-to-quarter and year-to-year due to changes in the assumptions used in the calculations.
General and administrative expenses	General and administrative expenses General and administrative expenses consist of personnel costs, including salaries, benefits, and non-cash stock-based compensation, for employees in finance, legal, executive, human resources, information technology, and other administrative functions, legal and consulting fees, recruiting costs, and facility costs not otherwise included in research and development expenses. Legal fees include those related to corporate and patent matters. General and administrative expenses for the twelve months ended December 31, 2022 include costs related to the November 2022 restructuring and construction in progress costs incurred in connection with the write-off of our previously planned manufacturing facility in Fremont, California (Fremont facility), which we plan to replace with our manufacturing facility in Bothell, Washington (the Bothell facility).
Income taxes	Income taxes The Company determines its deferred tax assets and liabilities based on the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that the deferred tax asset will not be recovered. The Company applies judgment in the determination of the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company recognizes any material interest and penalties related to unrecognized tax benefits in income tax expense. The Company is required to file income tax returns in the United States (U.S.) federal jurisdiction, and other state and local jurisdictions. The Company is generally subject to examination by U.S. federal and local income tax authorities for all tax years in which the loss carryforward is available. The Company is currently not under examination by the Internal Revenue Service or other jurisdictions for any tax years.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
JOBS Act accounting election	JOBS Act accounting election The Company is an emerging growth company (EGC), as defined in the Jumpstart Our Business Startups Act of 2012 (JOBS Act). Under the JOBS Act, an EGC can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies; however, the Company may adopt new or revised accounting standards early if the standard allows for early adoption. In addition, the Company will utilize other exemptions and reduced reporting requirements provided to EGCs by the JOBS Act. Subject to certain conditions set forth in the JOBS Act, an EGC is not required to, among other things, (i) provide an auditor’s attestation report on the company’s system of internal controls over financial reporting pursuant to Section 404(b) of the Sarbanes- Oxley Act of 2002, (ii) provide all of the compensation disclosure that may be required of non- EGC public companies under the Dodd-Frank Wall Street Reform and Consumer Protection Act, (iii) comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regarding mandatory audit firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financial statements (auditor discussion and analysis) , or (iv) disclose certain executive compensation-related items , such as the correlation between executive compensation and performance and comparisons of the c hief e xecutive o fficer’s compensation to median employee compensation.
Recent accounting pronouncements	Recent accounting pronouncements Recently adopted ASU No. 2017-04 , Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment

Acquisitions - (Tables)

Acquisitions - (Tables)	12 Months Ended
	Dec. 31, 2022
Cobalt Biomedicine, Inc
Business Acquisition [Line Items]
Schedule of Various Thresholds for Market Capitalizations Resulting Potential Success Payment and Additional Potential Contingent Consideration	The following table sets forth various thresholds for the Company’s market capitalizations as of the date of a change of control and the resulting potential Cobalt Success Payment and additional potential Cobalt Contingent Consideration: Sana market capitalization upon a change of control and resulting impact to Cobalt Success Payment and additional potential Cobalt Contingent Consideration Cobalt Success Payment Additional potential Cobalt Contingent Consideration (in millions) Equal to or exceeds $8.1 billion $ 500 $ - Equal to or exceeds $7.4 billion, but less than $8.1 billion 150 350 Equal to or exceeds $6.8 billion, but less than $7.4 billion 100 400 Less than $6.8 billion - 500

License and collaboration agr_2

License and collaboration agreements (Tables)	12 Months Ended
	Dec. 31, 2022
License And Collaboration Agreements [Abstract]
Summary of Potential Success Payments	Multiple of Equity Value at Issuance 5x 10x 20x 30x 40x Per share common stock price required for payment $ 20.00 $ 40.00 $ 80.00 $ 120.00 $ 160.00 Success payment(s) (in millions) $ 5.0 $ 15.0 $ 30.0 $ 50.0 $ 75.0

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Assets and Liabilities Measured on Recurring Basis	The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis based on the three-tier fair value hierarchy: December 31, 2022 Valuation Hierarchy Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Estimated Fair Value (in thousands) Financial assets: Cash equivalents: Money market funds Level 1 $ 114,363 $ - $ - $ 114,363 U.S. government and agency securities Level 2 40,532 10 - 40,542 Corporate debt securities Level 2 9,796 1 (2 ) 9,795 Total cash equivalents 164,691 11 (2 ) 164,700 Short-term marketable securities: U.S. government and agency securities Level 2 222,435 2 (3,711 ) 218,726 Corporate debt securities Level 2 28,836 - (364 ) 28,472 Total short-term marketable securities 251,271 2 (4,075 ) 247,198 Long-term marketable securities: U.S. government and agency securities Level 2 10,314 - (263 ) 10,051 Total long-term marketable securities 10,314 - (263 ) 10,051 Other assets Level 3 369 - - 369 Total financial assets $ 426,645 $ 13 $ (4,340 ) $ 422,318 Financial liabilities: Short-term financial liabilities: $ - Contingent consideration Level 3 $ 55,345 $ - $ - $ 55,345 Total short-term financial liabilities 55,345 - - 55,345 Long-term financial liabilities: Contingent consideration Level 3 95,034 - - 95,034 Success payment liabilities Level 3 21,007 - - 21,007 Total long-term financial liabilities 116,041 - - 116,041 Total financial liabilities $ 171,386 $ - $ - $ 171,386 December 31, 2021 Valuation Hierarchy Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Estimated Fair Value (in thousands) Financial assets: Cash equivalents: Money market funds Level 1 $ 224,671 $ - $ - $ 224,671 Corporate debt securities Level 2 2,345 - - 2,345 Total cash equivalents 227,016 - - 227,016 Short-term marketable securities: U.S. government and agency securities Level 2 162,854 1 (195 ) 162,660 Corporate debt securities Level 2 135,441 - (134 ) 135,307 Total short-term marketable securities 298,295 1 (329 ) 297,967 Long-term marketable securities: U.S. government and agency securities Level 2 176,492 - (925 ) 175,567 Corporate debt securities Level 2 20,427 - (113 ) 20,314 Total long-term marketable securities 196,919 - (1,038 ) 195,881 Other assets Level 3 426 - - 426 Total financial assets $ 722,656 $ 1 $ (1,367 ) $ 721,290 Financial liabilities: Short-term financial liabilities: Contingent consideration Level 3 $ 51,382 $ - $ - $ 51,382 Success payment liabilities Level 3 5,000 - - 5,000 Total short-term financial liabilities 56,382 - - 56,382 Long-term financial liabilities: Contingent consideration Level 3 102,361 - - 102,361 Success payment liabilities Level 3 97,525 - - 97,525 Total long-term financial liabilities 199,886 - - 199,886 Total financial liabilities $ 256,268 $ - $ - $ 256,268
Summary of Estimated Fair Value Available For Sale Debt Securities Continuous Unrealized Loss Position	The following table summarizes available-for-sale debt securities in a continuous unrealized loss position for less than and greater than twelve months, for the periods presented: Less than 12 months 12 months or greater Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses (in thousands) December 31, 2022 U.S. government and agency securities $ 49,253 $ (673 ) $ 172,845 $ (3,301 ) $ 222,098 $ (3,974 ) Corporate debt securities 13,333 (16 ) 19,664 (350 ) 32,997 (366 ) Total $ 62,586 $ (689 ) $ 192,509 $ (3,651 ) $ 255,095 $ (4,340 ) December 31, 2021 U.S. government and agency securities $ 329,883 $ (1,120 ) $ - $ - $ 329,883 $ (1,120 ) Corporate debt securities 156,662 (247 ) - - 156,662 (247 ) Total $ 486,545 $ (1,367 ) $ - $ - $ 486,545 $ (1,367 )
Changes in Estimated Fair Value of Level 3 Financial Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities: Contingent Consideration Cobalt Success Payment Liability Harvard Success Payment Liability (in thousands) Balance as of December 31, 2021 $ 153,743 $ 88,353 $ 14,172 Changes in fair value - gain (528 ) (46,823 ) (8,087 ) Balance as of March 31, 2022 153,215 41,530 6,085 Changes in fair value - gain (3,830 ) (12,073 ) (2,025 ) Balance as of June 30, 2022 149,385 29,457 4,060 Changes in fair value - expense (gain) (8,255 ) 2,439 (246 ) Balance as of September 30, 2022 141,130 31,896 3,814 Changes in fair value - expense (gain) 9,249 (12,880 ) (1,823 ) Balance as of December 31, 2022 $ 150,379 $ 19,016 $ 1,991
Success Payment Liabilities
Summary of Estimated Fair Value of Liabilities using Unobservable Inputs	The fair values of the Cobalt Success Payments and Harvard success Payments were calculated using the following unobservable inputs: December 31, 2022 2021 Unobservable Input Cobalt Harvard Cobalt Harvard Expected stock price volatility 70% 70% 70% 70% Expected term (years) 16.1 8.2 17.1 9.2
Cobalt Contingent Consideration
Summary of Estimated Fair Value of Liabilities using Unobservable Inputs	The fair value of the Cobalt Contingent Consideration was calculated using the following unobservable inputs: December 31, 2022 2021 Unobservable Input Range Weighted-Average Range Weighted-Average Discount rates 13.4% - 15.1% 14.6% 10.9% - 11.6% 11.2% Probability of milestone achievement 5.0% - 85.0% 36.0% 5.0% - 75.0% 33.8%

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consists of the following: December 31, 2022 2021 (in thousands) Laboratory equipment $ 61,842 $ 47,684 Leasehold improvements 34,427 33,848 Construction in progress 1,711 1,388 Computer equipment, software, and other 2,914 1,318 Total property and equipment, at cost 100,894 84,238 Less: Accumulated depreciation (33,977 ) (18,774 ) Property and equipment, net $ 66,917 $ 65,464

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Payables And Accruals [Abstract]
Schedule of Accrued Compensation and Accrued Expenses and Other Current Liabilities	Accrued compensation and accrued expenses and other current liabilities consist of the following: December 31, 2022 2021 (in thousands) Accrued compensation: Accrued bonuses $ 16,455 $ 13,814 Accrued paid time off 4,794 4,429 Accrued payroll 5,113 2,888 Total accrued compensation $ 26,362 $ 21,131 Accrued expenses and other current liabilities: Accrued research and development services $ 8,733 $ 3,419 Accrued professional fees 1,158 1,971 Accrued property and equipment 1,790 2,566 Other accrued current liabilities 2,866 2,388 Total accrued expenses and other current liabilities $ 14,547 $ 10,344

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Schedule of Additional Information Related to Operating Leases	The following table contains additional information related to the Company’s operating leases: Location Use Approximate Square Footage Commencement Dates Expiration Dates Seattle, WA Office/Laboratory 48,000 March 2019 to September 2020 December 2026 to April 2028 Cambridge, MA Office/Laboratory 60,000 March 2019 to January 2022 December 2025 to February 2028 South San Francisco, CA Office/Laboratory 100,000 December 2019 to April 2022 April 2024 to April 2030 Fremont, CA Industrial 163,000 July 2021 November 2031 Rochester, NY Office/Laboratory 3,000 January 2022 January 2025 Bothell, WA Office/Laboratory/Industrial 80,000 January 2023 January 2039
Summary of Lease Costs	The following table summarizes the Company’s lease costs: Year Ended December 31, 2022 2021 2020 (in thousands) Operating lease cost $ 23,881 $ 16,425 $ 10,757 Short-term lease cost - 512 1,886 Variable lease cost 7,193 5,230 3,081 Total lease cost $ 31,074 $ 22,167 $ 15,724
Reconciliation of Undiscounted Operating Lease Cash Flows by Fiscal Year to Present Value of Operating Lease Liabilities	The following table reconciles the Company’s undiscounted operating lease cash flows by fiscal year to the present value of the operating lease liabilities as of December 31, 2022 (in thousands): 2023 $ 23,523 2024 24,321 2025 24,298 2026 21,343 2027 18,736 2028 and thereafter 36,367 Total undiscounted lease payments 148,588 Less: imputed interest (39,018 ) Less: tenant improvement allowances (1,317 ) Present value of operating lease liabilities 108,253 Less: current portion of operating lease liabilities (12,393 ) Operating lease liabilities, net of current portion $ 95,860

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock Based Compensation Expense Recognized	Stock-based compensation expense is recognized in the consolidated statements of operations as follows: Year Ended December 31, 2022 2021 2020 (in thousands) Research and development $ 26,583 $ 15,239 $ 4,888 General and administrative (1) 11,754 7,123 940 Total stock-based compensation expense $ 38,337 $ 22,362 $ 5,828 (1)
Schedule of Unrecognized Stock-Based Compensation Costs Related to Unvested Awards and Weighted-Average Period Over Which Costs are Expected to be Recognized	Unrecognized stock-based compensation costs related to unvested awards and the weighted-average period over which the costs are expected to be recognized as of December 31, 2022 are as follows: Stock Options RSAs RSUs Unrecognized stock-based compensation expense (in thousands) $ 73,291 $ 13 $ 4,209 Weighted-average period costs expected to be recognized (in years) 2.7 0.3 2.2
Summary of Stock Option Activity	A summary of the Company’s stock option activity is as follows: Stock Options (in thousands) Weighted-Average Exercise Price per Share Weighted-Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2021 17,337 $ 8.96 8.7 $ 141,718 Granted 11,949 6.09 Exercised (1,062 ) 2.10 Forfeited/Cancelled (4,538 ) 9.12 Outstanding as of December 31, 2022 23,686 $ 7.79 8.3 $ 10,628 Exercisable as of December 31, 2022 7,402 $ 7.32 7.3 $ 7,648
Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Estimating Fair Value of Stock Options Granted	The fair value of stock options granted to employees, directors, and consultants was estimated on the date of grant using the Black-Scholes option pricing model using the following assumptions: Assumptions 2022 2021 2020 Risk free interest rate 1.56% - 4.31% 0.46% - 1.38% 0.36% - 1.51% Expected volatility 70% 70% 70% Expected term (years) 5.50 - 6.25 5.50 - 6.40 6.25 - 6.75 Expected dividend 0% 0% 0%
Summary of Additional Information Related to Stock Option Activity	The following table summarizes additional information related to stock option activity: 2022 2021 2020 Weighted average grant date fair value per share for options granted $ 3.92 $ 14.22 $ 3.52 Aggregate intrinsic value of stock options exercised (in thousands) $ 6,133 $ 29,880 $ 605
Summary of RSA and RSU Activity	A summary of the Company’s RSA and RSU activity is as follows: RSAs (in thousands) RSAs Weighted-Average Grant Date Fair Value per Share RSUs (in thousands) RSUs Weighted-Average Grant Date Fair Value per Share Unvested shares as of December 31, 2021 4,365 $ 0.43 141 $ 9.43 Granted - - 1,075 6.21 Vested (4,309 ) 0.42 (86 ) 9.52 Forfeited (44 ) 0.94 (245 ) 5.38 Unvested shares as of December 31, 2022 12 $ 1.44 885 $ 6.66

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Reconciliation of Income Taxes Computed Using U.S Federal Statutory Tax Rate	A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows: Year Ended December 31, 2022 2021 2020 Federal statutory tax 21.00 % 21.00 % 21.00 % State income tax, net of federal benefit 13.49 2.75 2.09 Valuation allowance (43.69 ) (24.06 ) (15.18 ) Success payment liabilities 5.40 (1.40 ) (4.58 ) Contingent consideration 0.26 (1.88 ) (3.89 ) Tax credits 4.93 2.58 1.88 Other (1.39 ) 1.01 (1.32 ) Effective income tax rate 0.00 % 0.00 % 0.00 %
Components of Net Deferred Tax Assets	The principal components of the Company’s net deferred tax assets are as follows: December 31, 2022 2021 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 154,888 $ 114,368 Capitalized research and development 49,687 - Tax credit carryforwards 44,051 24,008 Lease liabilities 28,050 25,754 Intangibles 7,949 5,986 Stock-based compensation 6,958 1,854 Accrued liabilities and allowances 6,807 4,401 Success payment liabilities 516 3,290 Other 155 - Gross deferred tax assets 299,061 179,661 Valuation allowance (274,348 ) (156,622 ) Deferred tax assets, net of valuation allowance 24,713 23,039 Deferred tax liabilities: Right-of-use assets (23,554 ) (21,940 ) Fixed assets (1,159 ) (1,050 ) Other - (49 ) Deferred tax liabilities (24,713 ) (23,039 ) Net deferred taxes assets $ - $ -

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following securities were excluded from the computation of net loss per diluted share of common stock for periods presented as their effect would have been anti-dilutive: Year Ended December 31, 2022 2021 2020 (in thousands) Convertible preferred stock - - 134,113 Options to purchase common stock 23,686 17,337 15,677 Unvested restricted common stock 12 4,365 10,079 Unvested RSUs 885 141 326 Total 24,583 21,843 160,195

Organization - Additional Infor

Organization - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Aug. 31, 2022
Description Of Organization [Line Items]
Stock-based compensation expense		$ 38,337,000	$ 22,362,000	$ 5,828,000
Net proceeds from issuance of common stock		601,000
Proceeds from public offering of common stock, net of offering costs			626,405,000
Accumulated deficit		1,054,836,000	$ 785,360,000
Cash, cash equivalents and marketable securities		434,000,000
Success payment liabilities		18,600,000
Contingent consideration		$ 99,100,000
At The Market Offering | Common Stock
Description Of Organization [Line Items]
Issuance of common stock, net of offering costs (in shares)		149
IPO | Common Stock
Description Of Organization [Line Items]
Issuance of common stock, net of offering costs (in shares)	27,000		27,025
Common stock price per share	$ 25
Proceeds from public offering of common stock, net of offering costs	$ 626,400,000
Payments of underwriting discounts and commissions	45,200,000
Offering expenses	$ 4,000,000
Underwriters' Option To Purchase Additional Shares | Common Stock
Description Of Organization [Line Items]
Issuance of common stock, net of offering costs (in shares)	3,500
Cowen | At The Market Offering
Description Of Organization [Line Items]
Common stock maximum aggregate offering price					$ 150,000,000
Net proceeds from issuance of common stock		$ 600,000
Portfolio Prioritization and Corporate Restructuring
Description Of Organization [Line Items]
Reduction workforce percentage		15%
Expenses related to employee severance, benefits, and related costs		$ 6,800,000
Stock-based compensation expense		$ 1,900,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020	Feb. 28, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Off-balance sheet concentrations of credit risk, description	The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts, or other hedging arrangements.
Goodwill	$ 140,627,000	$ 140,627,000
Amortization of intangible asset	0
Impairments of intangible asset	$ 0
Expected dividend yield	0%	0%	0%
Number of operating segment | Segment	1
Acquisition Agreement | Cobalt Biomedicine, Inc
Summary Of Significant Accounting Policies [Line Items]
Goodwill	$ 140,600,000			$ 140,600,000
Impairments of goodwill	$ 0
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	5 years

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 28, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill		$ 140,627,000	$ 140,627,000
Estimated fair value of contingent consideration, short term liabilities		55,345,000	51,382,000
Estimated fair value of contingent consideration, long-term liabilities		95,034,000	102,361,000
Change in fair value of contingent consideration		(3,364,000)	31,842,000	$ 52,793,000
Cobalt Biomedicine, Inc | Acquisition Agreement
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	100%
Goodwill	$ 140,600,000	140,600,000
Maximum contingent consideration upon achievement of certain pre-specified development milestones	500,000,000
Cobalt Biomedicine, Inc | Acquisition Agreement | Research and Development Expense
Business Acquisition [Line Items]
Estimated fair value of contingent consideration		150,400,000	153,700,000
Estimated fair value of contingent consideration, short term liabilities		55,400,000	51,400,000
Estimated fair value of contingent consideration, long-term liabilities		95,000,000	102,300,000
Change in estimated fair value of success payment		69,300,000	(23,600,000)	(62,300,000)
Change in fair value of contingent consideration		3,400,000	31,800,000	$ 52,800,000
Cobalt Biomedicine, Inc | Acquisition Agreement | Research and Development Expense | Long-term Liabilities
Business Acquisition [Line Items]
Estimated fair value of success payment liability		$ 19,000,000	$ 88,300,000
Cobalt Biomedicine, Inc | Acquisition Agreement | Minimum
Business Acquisition [Line Items]
Threshold market capitalization	8,100,000,000
Cobalt Biomedicine, Inc | Acquisition Agreement | Market Capitalization Equal to or Exceeds $8.1 billion
Business Acquisition [Line Items]
Cobalt success payment	500,000,000
Cobalt Biomedicine, Inc | Acquisition Agreement | IPR&D
Business Acquisition [Line Items]
Business combination, intangible assets	$ 59,200,000

Acquisitions - Schedule of Vari

Acquisitions - Schedule of Various Thresholds for Market Capitalizations Resulting Potential Success Payment and Additional Potential Contingent Consideration (Details) - Cobalt Biomedicine, Inc $ in Millions	1 Months Ended
	Feb. 28, 2019 USD ($)
Market Capitalization Equal to or Exceeds $8.1 billion
Business Acquisition [Line Items]
Cobalt Success Payment	$ 500
Market Capitalization Equal to or exceeds $7.4 billion, but less than $8.1 billion
Business Acquisition [Line Items]
Cobalt Success Payment	150
Additional potential Cobalt Contingent Consideration	350
Market Capitalization Equal to or exceeds $6.8 billion, but less than $7.4 billion
Business Acquisition [Line Items]
Cobalt Success Payment	100
Additional potential Cobalt Contingent Consideration	400
Market Capitalization Less than $6.8 billion
Business Acquisition [Line Items]
Additional potential Cobalt Contingent Consideration	$ 500

Acquisitions - Schedule of Va_2

Acquisitions - Schedule of Various Thresholds for Market Capitalizations Resulting Potential Success Payment and Additional Potential Contingent Consideration (Parenthetical) (Details) - Sana $ in Billions	Feb. 28, 2019 USD ($)
Market Capitalization Equal to or Exceeds $8.1 billion
Business Acquisition [Line Items]
Threshold market capitalization	$ 8.1
Market Capitalization Equal to or exceeds $7.4 billion, but less than $8.1 billion
Business Acquisition [Line Items]
Threshold market capitalization	7.4
Market Capitalization Equal to or exceeds $6.8 billion, but less than $7.4 billion
Business Acquisition [Line Items]
Threshold market capitalization	6.8
Market Capitalization Less than $6.8 billion
Business Acquisition [Line Items]
Threshold market capitalization	$ 6.8

License and Collaboration Agr_3

License and Collaboration Agreements - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Oct. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock shares issued				$ 680,000
Beam Therapeutics Inc. (Beam) | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment to collaborators			$ 50,000,000
Beam Therapeutics Inc. (Beam) | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Developmental and commercial milestone payments and royalties on licensed products payable					$ 65,000,000
Beam Therapeutics Inc. (Beam) | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Beneficial ownership percentage held by a member of board of directors					10%
Harvard College
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregated consideration paid	$ 12,000,000
Common stock shares issued	9,000,000
Payment to collaborators	$ 3,000,000
Share issue price	$ 4
Maximum period expected to achieve for success payments	12 years
Estimated fair value of success payment liability			14,200,000
Harvard College | Short-term Liabilities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Estimated fair value of success payment liability			5,000,000
Harvard College | Long-term Liabilities
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Estimated fair value of success payment liability		$ 2,000,000	9,200,000
Harvard College | Research and Development Expense
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Expense in connection with change in estimated fair value of success payment liability		$ 12,200,000	$ (2,400,000)	$ (9,900,000)
Harvard College | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cobalt success payment	$ 175,000,000

License and Collaboration Agr_4

License and Collaboration Agreements - Summary of Potential Success Payments (Details) - Harvard College $ / shares in Units, $ in Millions	1 Months Ended
	Mar. 31, 2019 USD ($) $ / shares
Multiple of Equity Value at Issuance, 5x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Per share common stock price required for payment | $ / shares	$ 20
Success payment(s) | $	$ 5
Multiple of Equity Value at Issuance, 10x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Per share common stock price required for payment | $ / shares	$ 40
Success payment(s) | $	$ 15
Multiple of Equity Value at Issuance, 20x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Per share common stock price required for payment | $ / shares	$ 80
Success payment(s) | $	$ 30
Multiple of Equity Value at Issuance, 30x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Per share common stock price required for payment | $ / shares	$ 120
Success payment(s) | $	$ 50
Multiple of Equity Value at Issuance, 40x
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Per share common stock price required for payment | $ / shares	$ 160
Success payment(s) | $	$ 75

Restricted Cash - Additional In

Restricted Cash - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) LettersOfCredit	Jul. 31, 2023 USD ($)	Dec. 31, 2021 USD ($)
Restricted Cash And Cash Equivalents Items [Line Items]
Standby letters of credit	$ 10,500		$ 8,800
Number of standby letters of credit | LettersOfCredit	2
Restricted cash and cash equivalents, noncurrent, nature of restriction, description	standby letters of credit
Restricted cash	$ 6,100
Fremont, California
Restricted Cash And Cash Equivalents Items [Line Items]
Standby letters of credit	$ 6,700
Fremont, California | Forecast
Restricted Cash And Cash Equivalents Items [Line Items]
Future letter of credit amount		$ 600

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	$ 164,691	$ 227,016
Gross Unrealized Holding Gains	11
Gross Unrealized Holding Losses	(2)
Estimated Fair Value	164,700	227,016
Cash Equivalents | Money Market Funds | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	114,363	224,671
Estimated Fair Value	114,363	224,671
Cash Equivalents | US Government Agencies Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	40,532
Gross Unrealized Holding Gains	10
Estimated Fair Value	40,542
Cash Equivalents | Corporate Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	9,796	2,345
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	(2)
Estimated Fair Value	9,795	2,345
Short-term Marketable Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	251,271	298,295
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	(4,075)	(329)
Estimated Fair Value	247,198	297,967
Short-term Marketable Securities | US Government Agencies Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	222,435	162,854
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	(3,711)	(195)
Estimated Fair Value	218,726	162,660
Short-term Marketable Securities | Corporate Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	28,836	135,441
Gross Unrealized Holding Losses	(364)	(134)
Estimated Fair Value	28,472	135,307
Long-term Marketable Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	10,314	196,919
Gross Unrealized Holding Losses	(263)	(1,038)
Estimated Fair Value	10,051	195,881
Long-term Marketable Securities | US Government Agencies Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	10,314	176,492
Gross Unrealized Holding Losses	(263)	(925)
Estimated Fair Value	10,051	175,567
Long-term Marketable Securities | Corporate Debt Securities | Fair Value, Inputs, Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost		20,427
Gross Unrealized Holding Losses		(113)
Estimated Fair Value		20,314
Other Assets | Fair Value, Inputs, Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	369	426
Estimated Fair Value	369	426
Financial Assets
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	426,645	722,656
Gross Unrealized Holding Gains	13	1
Gross Unrealized Holding Losses	(4,340)	(1,367)
Estimated Fair Value	422,318	721,290
Short-term Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	55,345	56,382
Estimated Fair Value	55,345	56,382
Short-term Financial Liabilities | Contingent consideration | Fair Value, Inputs, Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	55,345	51,382
Estimated Fair Value	55,345	51,382
Short-term Financial Liabilities | Success Payment Liabilities | Fair Value, Inputs, Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost		5,000
Estimated Fair Value		5,000
Long-term Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	116,041	199,886
Estimated Fair Value	116,041	199,886
Long-term Financial Liabilities | Contingent consideration | Fair Value, Inputs, Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	95,034	102,361
Estimated Fair Value	95,034	102,361
Long-term Financial Liabilities | Success Payment Liabilities | Fair Value, Inputs, Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	21,007	97,525
Estimated Fair Value	21,007	97,525
Financial Liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	171,386	256,268
Estimated Fair Value	$ 171,386	$ 256,268

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Estimated Fair Value Available For Sale Debt Securities Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value less than 12 months	$ 62,586	$ 486,545
Unrealized losses less than 12 months	(689)	(1,367)
Fair value 12 months or greater	192,509
Unrealized losses 12 months or greater	3,651
Total fair value	255,095	486,545
Total unrealized losses	4,340	1,367
US Government Agencies Debt Securities
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value less than 12 months	49,253	329,883
Unrealized losses less than 12 months	(673)	(1,120)
Fair value 12 months or greater	172,845
Unrealized losses 12 months or greater	3,301
Total fair value	222,098	329,883
Total unrealized losses	3,974	1,120
Corporate Debt Securities
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value less than 12 months	13,333	156,662
Unrealized losses less than 12 months	(16)	(247)
Fair value 12 months or greater	19,664
Unrealized losses 12 months or greater	350
Total fair value	32,997	156,662
Total unrealized losses	$ 366	$ 247

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Maximum	12 Months Ended
	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities maturity period	2 years
Investments in securities with maturities period	1 year

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Estimated Fair Value of Level 3 Financial Liabilities (Details) - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Contingent Consideration
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 141,130	$ 149,385	$ 153,215	$ 153,743
Changes in fair value - expense (gain)	9,249	(8,255)	(3,830)	(528)
Ending Balance	150,379	141,130	149,385	153,215
Cobalt Success Payment Liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	31,896	29,457	41,530	88,353
Changes in fair value - expense (gain)	(12,880)	2,439	(12,073)	(46,823)
Ending Balance	19,016	31,896	29,457	41,530
Harvard Success Payment Liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	3,814	4,060	6,085	14,172
Changes in fair value - expense (gain)	(1,823)	(246)	(2,025)	(8,087)
Ending Balance	$ 1,991	$ 3,814	$ 4,060	$ 6,085

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Estimated Fair Value of Contingent Consideration Unobservable Inputs (Details)	Dec. 31, 2022	Dec. 31, 2021
Minimum | Discount Rates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.134	0.109
Minimum | Probability of Milestone Achievement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.050	0.050
Maximum | Discount Rates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.151	0.116
Maximum | Probability of Milestone Achievement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.850	0.750
Weighted-Average | Discount Rates
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.146	0.112
Weighted-Average | Probability of Milestone Achievement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value contingent consideration measurement input	0.360	0.338

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Estimated Fair Value of Success Payment Liabilities Unobservable Inputs (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cobalt | Expected Stock Price Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input	0.70	0.70
Cobalt | Expected Term (Years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input expected term (years)	16 years 1 month 6 days	17 years 1 month 6 days
Harvard | Expected Stock Price Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input	0.70	0.70
Harvard | Expected Term (Years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input expected term (years)	8 years 2 months 12 days	9 years 2 months 12 days

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 100,894	$ 84,238
Less: Accumulated depreciation	(33,977)	(18,774)
Property and equipment, net	66,917	65,464
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	61,842	47,684
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, at cost	34,427	33,848
Construction In Progress
Property Plant And Equipment [Line Items]
Property and equipment, at cost	1,711	1,388
Computer Equipment, Software and Other
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 2,914	$ 1,318

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation expense	$ 15,625	$ 11,070	$ 5,921

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Compensation and Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued compensation:
Accrued bonuses	$ 16,455	$ 13,814
Accrued paid time off	4,794	4,429
Accrued payroll	5,113	2,888
Total accrued compensation	26,362	21,131
Accrued expenses and other current liabilities:
Accrued research and development services	8,733	3,419
Accrued professional fees	1,158	1,971
Accrued property and equipment	1,790	2,566
Other accrued current liabilities	2,866	2,388
Total accrued expenses and other current liabilities	$ 14,547	$ 10,344

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($) ft²	Dec. 31, 2022 USD ($)
Lessee Lease Description [Line Items]
Obligation to pay base rent		$ 148,588
Weighted-average remaining lease term		6 years 2 months 12 days
Weighted-average incremental borrowing rate		9.68%
Bothell, Washington
Lessee Lease Description [Line Items]
Square feet | ft²	79,565
Initial lease term	16 years
Option to extend the lease term		the option to extend the lease for up to three additional five-year terms.
Reimbursement of tenant improvements	$ 19,900
Optional additional tenant improvement allowance	$ 8,000
Optional additional tenant improvement allowance, interest rate	6.50%
Obligation to pay base rent	$ 68,800
Letter of credit	$ 1,600
Fremont, California
Lessee Lease Description [Line Items]
Option to extend the lease term		option to renew the lease for two additional five-year terms.
Increase decrease in operating lease right-of-use assets		$ 12,800
Increase decrease in operating lease right-of-use liabilities		12,800
Construction in progress costs write-off		$ 4,500

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Additional Information Related to Operating Leases (Details) - ft²	1 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2022
Seattle, WA | Office/Laboratory
Lessee Lease Description [Line Items]
Square feet		48,000
Commencement Dates, Beginning		2019-03
Commencement Dates, Ending		2020-09
Lease arrangement, contractual expiration period, beginning year		2026-12
Lease arrangement, contractual expiration period, ending year		2028-04
Cambridge, MA | Office/Laboratory
Lessee Lease Description [Line Items]
Square feet		60,000
Commencement Dates, Beginning		2019-03
Commencement Dates, Ending		2022-01
Lease arrangement, contractual expiration period, beginning year		2025-12
Lease arrangement, contractual expiration period, ending year		2028-02
South San Francisco, CA | Office/Laboratory
Lessee Lease Description [Line Items]
Square feet		100,000
Commencement Dates, Beginning		2019-12
Commencement Dates, Ending		2022-04
Lease arrangement, contractual expiration period, beginning year		2024-04
Lease arrangement, contractual expiration period, ending year		2030-04
Fremont, CA | Industrial
Lessee Lease Description [Line Items]
Square feet		163,000
Commencement Dates, Beginning		2021-07
Lease arrangement, contractual expiration period, ending year		2031-11
Rochester, NY | Office/Laboratory
Lessee Lease Description [Line Items]
Square feet		3,000
Commencement Dates, Beginning		2022-01
Lease arrangement, contractual expiration period, ending year		2025-01
Bothell, WA
Lessee Lease Description [Line Items]
Square feet	79,565
Bothell, WA | Office/Laboratory/Industrial
Lessee Lease Description [Line Items]
Square feet		80,000
Commencement Dates, Beginning		2023-01
Lease arrangement, contractual expiration period, ending year		2039-01

Commitments and Contingencies_3

Commitments and Contingencies - Summary of Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lease, Cost [Abstract]
Operating lease cost	$ 23,881	$ 16,425	$ 10,757
Short-term lease cost		512	1,886
Variable lease cost	7,193	5,230	3,081
Total lease cost	$ 31,074	$ 22,167	$ 15,724

Commitments and Contingencies_4

Commitments and Contingencies - Reconciliation of Undiscounted Operating Lease Cash Flows by Fiscal Year to Present Value of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
2023	$ 23,523
2024	24,321
2025	24,298
2026	21,343
2027	18,736
2028 and thereafter	36,367
Total undiscounted lease payments	148,588
Less: imputed interest	(39,018)
Less: tenant improvement allowances	(1,317)
Present value of operating lease liabilities	108,253
Less: current portion of operating lease liabilities	(12,393)	$ (9,159)
Operating lease liabilities, net of current portion	$ 95,860	$ 101,784

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2022	Aug. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common stock, shares outstanding	191,022		184,929
Net proceeds from issuance of common stock	$ 601,000
Cowen | At The Market Offering
Class Of Stock [Line Items]
Common stock maximum aggregate offering price		$ 150,000,000
Net proceeds from issuance of common stock	$ 600,000
Restricted Stock
Class Of Stock [Line Items]
Common stock outstanding	12		4,365

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense		$ 38,337	$ 22,362	$ 5,828
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of vested		1,800	1,500	$ 1,500
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of vested		$ 500	$ 4,100
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage related to employees able to purchase shares at lower of fair market value	85%
Number of shares available for future issuance		3.3
2021 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage allowed for eligible employees to purchase shares of common stock	15%
2021 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance		14.4
Total stock-based compensation expense		$ 1,900

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense		$ 38,337	$ 22,362	$ 5,828
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense		26,583	15,239	4,888
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	[1]	$ 11,754	$ 7,123	$ 940
[1]During the year ended December 31, 2022 the Company recognized stock-based compensation expense of $1.9 million related to equity awards for employees impacted by the November 2022 restructuring.

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Unrecognized Stock-Based Compensation Costs Related to Unvested Awards and Weighted-Average Period Over Which Costs are Expected to be Recognized (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense (in thousands)	$ 73,291
Weighted-average period costs expected to be recognized (in years)	2 years 8 months 12 days
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense (in thousands)	$ 13
Weighted-average period costs expected to be recognized (in years)	3 months 18 days
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense (in thousands)	$ 4,209
Weighted-average period costs expected to be recognized (in years)	2 years 2 months 12 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock Options
Stock Options Outstanding, Beginning Balance	17,337
Stock Options, Granted	11,949
Stock Options, Exercised	(1,062)
Stock Options, Forfeited/Cancelled	(4,538)
Stock Options Outstanding, Ending Balance	23,686	17,337
Stock Options Exercisable	7,402
Weighted-Average Exercise Price per Share
Weighted-Average Exercise Price per Share Outstanding, Beginning Balance	$ 8.96
Weighted-Average Exercise Price per Share, Granted	6.09
Weighted-Average Exercise Price per Share, Exercised	2.10
Weighted-Average Exercise Price per Share, Forfeited/Cancelled	9.12
Weighted-Average Exercise Price per Share Outstanding, Ending Balance	7.79	$ 8.96
Weighted-Average Exercise Price Per Share Exercisable	$ 7.32
Weighted-Average Remaining Contractual Life (years)
Weighted-Average Remaining Contractual Life (years), Outstanding	8 years 3 months 18 days	8 years 8 months 12 days
Weighted-Average Remaining Contractual Life (years), Exercisable	7 years 3 months 18 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding	$ 10,628	$ 141,718
Aggregate Intrinsic Value, Exercisable	$ 7,648

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Assumptions Used in Black-Scholes Option-Pricing Model for Estimating Fair Value of Stock Options Granted (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk free interest rate, minimum	1.56%	0.46%	0.36%
Risk free interest rate, maximum	4.31%	1.38%	1.51%
Expected volatility	70%	70%	70%
Expected dividend	0%	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	5 years 6 months	5 years 6 months	6 years 3 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 years 3 months	6 years 4 months 24 days	6 years 9 months

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Additional Information Related to Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted average grant date fair value per share for options granted	$ 3.92	$ 14.22	$ 3.52
Aggregate intrinsic value of stock options exercised (in thousands)	$ 6,133	$ 29,880	$ 605

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of RSA and RSU Activity (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Restricted Stock
RSAs
Unvested shares as of December 31, 2021 | shares	4,365
Vested | shares	(4,309)
Forfeited | shares	(44)
Unvested shares as of December 31, 2022 | shares	12
Weighted-Average Grant Date Fair Value per Share
Unvested shares as of December 31, 2021 | $ / shares	$ 0.43
Vested | $ / shares	0.42
Forfeited | $ / shares	0.94
Unvested shares as of December 31, 2022 | $ / shares	$ 1.44
Restricted Stock Units (RSUs)
RSAs
Unvested shares as of December 31, 2021 | shares	141
Granted | shares	1,075
Vested | shares	(86)
Forfeited | shares	(245)
Unvested shares as of December 31, 2022 | shares	885
Weighted-Average Grant Date Fair Value per Share
Unvested shares as of December 31, 2021 | $ / shares	$ 9.43
Granted | $ / shares	6.21
Vested | $ / shares	9.52
Forfeited | $ / shares	5.38
Unvested shares as of December 31, 2022 | $ / shares	$ 6.66

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Income Taxes [Line Items]
Net operating loss carryforwards, federal	$ 120,200
Net operating loss carryforwards, state	34,600
Deferred tax asset capitalized research and development	$ 49,687
State
Income Taxes [Line Items]
Net tax operating losses, expiration	begin to expire in 2036
Tax credit carryforward, expiration	begin to expire in 2037
Research tax credits	$ 13,300
Federal
Income Taxes [Line Items]
Research tax credits	30,800
Federal net operating losses, indefinite life	$ 118,600

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Taxes Computed Using U.S Federal Statutory Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]
Federal statutory tax	21%	21%	21%
State income tax, net of federal benefit	13.49%	2.75%	2.09%
Valuation allowance	(43.69%)	(24.06%)	(15.18%)
Success payment liabilities	5.40%	(1.40%)	(4.58%)
Contingent consideration	0.26%	(1.88%)	(3.89%)
Tax credits	4.93%	2.58%	1.88%
Other	(1.39%)	1.01%	(1.32%)
Effective income tax rate	0%	0%	0%

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforwards	$ 154,888	$ 114,368
Capitalized research and development	49,687
Tax credit carryforwards	44,051	24,008
Lease liabilities	28,050	25,754
Intangibles	7,949	5,986
Stock-based compensation	6,958	1,854
Accrued liabilities and allowances	6,807	4,401
Success payment liabilities	516	3,290
Other	155
Gross deferred tax assets	299,061	179,661
Valuation allowance	(274,348)	(156,622)
Deferred tax assets, net of valuation allowance	24,713	23,039
Deferred tax liabilities:
Right-of-use assets	(23,554)	(21,940)
Fixed assets	(1,159)	(1,050)
Other		(49)
Deferred tax liabilities	$ (24,713)	$ (23,039)

Net Loss Per Share - Anti-dilut

Net Loss Per Share - Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of dilutive net loss per share	24,583	21,843	160,195
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of dilutive net loss per share			134,113
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of dilutive net loss per share	23,686	17,337	15,677
Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of dilutive net loss per share	12	4,365	10,079
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of dilutive net loss per share	885	141	326

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Maximum
Defined Contribution Plan Disclosure [Line Items]
Matching contribution by employer under retirement and savings plan	$ 4,000