Relay Therapeutics (RLAY) 10-K22 Feb 242023 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Registrant Name	RELAY THERAPEUTICS, INC.
Entity Central Index Key	0001812364
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 1.5
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		131,179,034
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	RLAY
Security Exchange Name	NASDAQ
Entity File Number	001-39385
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3923475
Entity Address, Address Line One	399 Binney Street
Entity Address, Address Line Two	2nd Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	370-8837
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE The Registrant intends to file a definitive proxy statement pursuant to Regulation 14A relating to the 2024 Annual Meeting of Stockholders within 120 days of the end of the registrant’s fiscal year ended December 31, 2023 . Portions of such definitive proxy statement are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts
Document Financial Statement Error Correction [Flag]	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 143,736	$ 151,794
Investments	606,350	847,123
Accounts receivable		306
Contract asset		4,913
Prepaid expenses	16,702	12,110
Other current assets	3,315	3,259
Total current assets	770,103	1,019,505
Property and equipment, net	10,901	11,634
Operating lease assets	57,969	63,754
Restricted cash	2,707	2,578
Intangible asset	2,300	2,300
Total assets	843,980	1,099,771
Current liabilities:
Accounts payable	9,211	10,578
Accrued expenses	14,890	22,703
Operating lease liabilities	4,964	4,276
Other current liabilities	1,204	26,152
Total current liabilities	30,269	63,709
Operating lease liabilities, net of current portion	48,502	53,466
Contingent consideration liability	13,206	32,378
Total liabilities	91,977	149,553
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized as of December 31, 2023, and December 31, 2022;127,462,409 and 121,112,234 shares issued and outstanding as of December 31, 2023 and December 31, 2022, respectively	127	121
Additional paid-in capital	2,152,654	2,019,126
Accumulated other comprehensive loss	(196)	(10,420)
Accumulated deficit	(1,400,582)	(1,058,609)
Total stockholders' equity	752,003	950,218
Total liabilities and stockholders' equity	$ 843,980	$ 1,099,771

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Common stock par value	$ 0.001	$ 0.001
Common stock shares authorized	300,000,000	300,000,000
Common stock shares issued	127,462,409	121,112,234
Common stock shares outstanding	127,462,409	121,112,234
Undesignated Preferred Stock [Member]
Preferred stock par value	$ 0.001	$ 0.001
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue:
License and other revenue	$ 25,546	$ 1,381	$ 3,029
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Total revenue	$ 25,546	$ 1,381	$ 3,029
Operating expenses:
Research and development expenses	330,018	246,355	172,650
In-process research and development expenses			123,000
Loss on initial consolidation of variable interest entity			11,855
Change in fair value of contingent consideration liability	(6,422)	(11,677)	2,836
General and administrative expenses	74,950	65,978	57,386
Total operating expenses	398,546	300,656	367,727
Loss from operations	(373,000)	(299,275)	(364,698)
Other income:
Interest income	31,045	8,786	830
Other expense	(18)	(20)	(4)
Total other income, net	31,027	8,766	826
Net loss	$ (341,973)	$ (290,509)	$ (363,872)
Net loss per share, basic	$ (2.79)	$ (2.59)	$ (3.82)
Net loss per share, diluted	$ (2.79)	$ (2.59)	$ (3.82)
Weighted average shares of common stock, basic	122,576,527	112,233,649	95,136,719
Weighted average shares of common stock, diluted	122,576,527	112,233,649	95,136,719
Other comprehensive loss:
Unrealized holding gain (loss)	$ 10,224	$ (9,332)	$ (1,152)
Total other comprehensive gain (loss)	10,224	(9,332)	(1,152)
Total comprehensive loss	$ (331,749)	$ (299,841)	$ (365,024)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2020	$ 763,293	$ 90	$ 1,167,367	$ 64	$ (404,228)
Beginning balance, shares at Dec. 31, 2020		89,906,835
Issuance of common stock upon acquisition of ZebiAI	62,992	$ 2	62,990
Issuance of common stock upon acquisition of ZebiAI, shares		1,914,219
Issuance of common stock through follow-on/at-the-market offerings, net	382,210	$ 15	382,195
Issuance of common stock through follow-on/at-the-market offerings, net shares		15,188,679
Issuance of common stock through exercise of stock options	4,739	$ 1	4,738
Issuance of common stock through exercise of stock options, shares		996,536
Issuance of common stock via employee stock purchase plan	1,141	$ 1	1,140
Issuance of common stock via employee stock purchase plan, shares		43,685
Vesting of restricted common stock	3		3
Vesting of restricted common stock ,shares		84,489
Vesting of restricted stock units, Shares		75,875
Stock compensation expense	48,454		48,454
Unrealized (loss) gain on investments	(1,152)			(1,152)
Net loss	(363,872)				(363,872)
Ending balance at Dec. 31, 2021	897,808	$ 109	1,666,887	(1,088)	(768,100)
Ending balance, shares at Dec. 31, 2021		108,210,318
Issuance of common stock upon milestone achievement,shares		301,939
Issuance of common stock upon milestone achievement	6,203		6,203
Issuance of common stock through follow-on/at-the-market offerings, net	284,744	$ 11	284,733
Issuance of common stock through follow-on/at-the-market offerings, net shares		11,320,755
Issuance of common stock through exercise of stock options	3,480	$ 1	3,479
Issuance of common stock through exercise of stock options, shares		757,873
Issuance of common stock via employee stock purchase plan	1,686		1,686
Issuance of common stock via employee stock purchase plan, shares		123,019
Vesting of restricted stock units, Shares		398,330
Stock compensation expense	56,138		56,138
Unrealized (loss) gain on investments	(9,332)			(9,332)
Net loss	(290,509)				(290,509)
Ending balance at Dec. 31, 2022	950,218	$ 121	2,019,126	(10,420)	(1,058,609)
Ending balance, shares at Dec. 31, 2022		121,112,234
Issuance of common stock upon milestone achievement,shares		1,797,064
Issuance of common stock upon milestone achievement	12,750	$ 2	12,748
Issuance of common stock through follow-on/at-the-market offerings, net	30,281	$ 3	30,278
Issuance of common stock through follow-on/at-the-market offerings, net shares		3,026,072
Issuance of common stock through exercise of stock options	1,986	$ 1	1,985
Issuance of common stock through exercise of stock options, shares		399,498
Issuance of common stock via employee stock purchase plan	2,486		2,486
Issuance of common stock via employee stock purchase plan, shares		244,125
Vesting of restricted stock units, Shares		883,416
Stock compensation expense	86,031		86,031
Unrealized (loss) gain on investments	10,224			10,224
Net loss	(341,973)				(341,973)
Ending balance at Dec. 31, 2023	$ 752,003	$ 127	$ 2,152,654	$ (196)	$ (1,400,582)
Ending balance, shares at Dec. 31, 2023		127,462,409

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (341,973)	$ (290,509)	$ (363,872)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock compensation expense	86,031	56,138	48,454
Depreciation expense	5,269	4,130	3,925
Net amortization of premiums and discounts on investments	(10,763)	1,182	2,052
Acquired in-process research and development			123,000
Loss on initial consolidation of variable interest entity			11,855
Change in fair value of contingent consideration liability	(6,422)	(11,677)	2,836
Changes in assets and liabilities:
Accounts receivable	306	97	74,677
Contract asset	4,913	(376)	3,117
Prepaid expenses and other current assets	(4,648)	(2,140)	(2,681)
Operating lease assets and liabilities, net	1,509	(8,132)	277
Other assets			22
Accounts payable	(2,394)	1,989	930
Accrued expenses and other liabilities	(32,144)	20,056	21,002
Deferred revenue		(248)
Net cash used in operating activities	(300,316)	(229,490)	(74,406)
Cash flows from investing activities:
Purchases of property and equipment	(4,126)	(9,062)	(3,471)
Purchases of investments	(385,542)	(535,419)	(980,665)
Proceeds from maturities of investments	647,302	355,736	529,923
Cash paid for acquisition of ZebiAI, net of cash acquired			(25,298)
Net cash provided by (used in) investing activities	257,634	(188,745)	(479,511)
Cash flows from financing activities:
Proceeds from issuance of common stock through follow-on offering, net		284,744	382,210
Proceeds from issuance of common stock through at-the-market offerings, net	30,281
Proceeds from issuance of common stock through exercise of stock options	1,986	3,480	4,739
Proceeds from issuance of common stock via employee stock purchase plan	2,486	1,686	1,141
Net cash provided by financing activities	34,753	289,910	388,090
Net decrease in cash, cash equivalents, and restricted cash	(7,929)	(128,325)	(165,827)
Cash, cash equivalents and restricted cash at beginning of period	154,372	282,697	448,524
Cash, cash equivalents and restricted cash at end of period	146,443	154,372	282,697
Supplemental disclosure of non-cash activities:
Periodic change to additions of property and equipment in current liabilities	410	159	1,010
Reclassification of restricted stock liability to additional paid-in capital			3
Issuance of common stock upon milestone achievement	$ 12,750	6,203
Operating lease assets obtained in exchange for operating lease liabilities		$ 46,626
ZebiAI [Member]
Supplemental disclosure of non-cash activities:
Assets obtained in asset acquisition of ZebiAI			662
Liabilities assumed in asset acquisition of ZebiAI			2,330
Fair value of common stock issued in asset acquisition of ZebiAI			$ 62,992

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Restricted Cash And Cash Equivalents At Carrying Value [Abstract]
Cash and cash equivalents	$ 143,736	$ 151,794
Restricted cash	2,707	2,578
Cash, cash equivalents, and restricted cash per statements of cash flows	$ 146,443	$ 154,372

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (341,973)	$ (290,509)	$ (363,872)

Insider Trading Arrangements

Insider Trading Arrangements - Directors and Officers [Member]	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Nature of Business and Basis of

Nature of Business and Basis of Presentation	12 Months Ended
Nature of Business and Basis of Presentation	Dec. 31, 2023
Text Block [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Relay Therapeutics, Inc. (the "Company") was incorporated in Delaware on May 4, 2015 and is headquartered in Cambridge, Massachusetts. The Company is a clinical-stage, precision medicine company transforming the drug discovery process by combining leading-edge computational and experimental technologies with the goal of bringing life-changing therapies to patients. As the Company believes it is among the first of a new breed of biotech created at the intersection of complementary techniques and technologies, the Company aims to push the boundaries of what’s possible in drug discovery. The Company’s Dynamo platform integrates an array of leading-edge computational and experimental approaches designed to drug protein targets that have previously been intractable or inadequately addressed. The Company’s initial focus is on enhancing small molecule therapeutic discovery in targeted oncology and genetic disease indications. The Company’s lead product candidates, RLY-2608, RLY-4008 (lirafugratinib), and GDC-1971 (migoprotafib, formerly known as RLY-1971), are in clinical development. The Company also has more than seven active discovery stage programs across both precision oncology and genetic diseases. The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations, and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities. The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval, or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. The Company has devoted substantially all of its resources to developing its product candidates by developing its computation and experimental approaches, building its intellectual property portfolio, business planning, raising capital and providing general and administrative support for these operations. The Company has incurred net operating losses since inception and had an accumulated deficit of $ 1.4 billion as of December 31, 2023. The Company expects that its existing cash, cash equivalents, and investments as of December 31, 2023 will enable it to fund its planned operating expenses and capital expenditure requirements for at least one year from the date of the issuance of these consolidated financial statements. The future viability of the Company is dependent on its ability to generate cash from operating activities or to raise additional capital to finance its operations. The Company’s failure to raise capital as and when needed could have a material adverse effect on its financial condition and ability to pursue its business strategies. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into license or collaboration arrangements or obtain government grants. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce, or eliminate its research and development programs, product portfolio expansion, or commercialization efforts, which could adversely affect its business prospects. In the event the Company requires additional funding, there can be no assurance that it will be successful in obtaining sufficient funding on terms acceptable to the Company to fund its continuing operations, if at all.

Significant Accounting Policie

Significant Accounting Policies	12 Months Ended
Significant Accounting Policies	Dec. 31, 2023
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") for reporting on Form 10-K. The Company’s consolidated financial statements include the accounts of Relay Therapeutics, Inc. and its wholly-owned subsidiaries, Relay Securities Corporation and Relay ML Discovery, LLC. All intercompany balances and transactions have been eliminated. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the fair value of contingent milestone payments in connection with the acquisition of ZebiAI Therapeutics, Inc. ("ZebiAI"), the determination of the transaction price and standalone selling price of performance obligations under Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 606, Revenue from Contracts with Customers ("ASC 606"), the accrual of research and development and manufacturing expenses, the valuation of equity instruments, and the incremental borrowing rate for determining operating lease assets and liabilities. Estimates are periodically reviewed in light of changes in circumstances, facts, and experience. Segment Information In general, 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 on how to allocate resources and assess performance. The Company's chief operating decision maker is the president and chief executive officer. The Company and the chief operating decision maker view the Company's operations as one operating segment. The Company's singular focus is on using innovative experimental and computational approaches on protein motion for making medicines to drug protein targets that have previously been intractable or inadequately addressed. The Company operates in the United States and all tangible assets are held in the United States. Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents. Cash equivalents, which consist of money market funds, are stated at fair value. Restricted Cash As of December 31, 2023 and 2022, the Company had restricted cash of $ 2.7 million and $ 2.6 million, respectively, to secure letters of credit in connection with operating leases of the Company’s facilities, as detailed in Note 13, Leases . The Company classified the restricted cash as a noncurrent asset on its consolidated balance sheets, consistent with the terms of the lease agreements. Investments Investments in marketable securities are classified as available-for-sale. Available-for-sale securities are measured and reported at fair value using quoted prices in active markets for similar securities. Premiums or discounts from par value are amortized to investment income over the life of the underlying investment. In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). Certain amendments thereto were also issued by the FASB. The Company adopted ASU 2016-13, as well as the related amendments thereto, on January 1, 2022, pursuant to which the Company reviews investments whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. In connection therewith, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors, considering the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security is compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded on the consolidated balance sheet, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that is not related to credit is recognized in other comprehensive loss as a separate component of stockholders' equity. Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense in general and administrative expenses within the consolidated statements of operations and comprehensive loss. Losses are charged against the allowance when the Company believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. All of the Company’s available-for-sale securities are available to the Company for use in current operations. As a result, the Company classified all such securities as current assets as of December 31, 2023 and 2022, although the stated maturity of some individual securities may be one year or more beyond the balance sheet dates. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in general and administrative expenses within the consolidated statements of operations and comprehensive loss. Concentration of Credit Risk and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and investments. From time to time, the Company has maintained all of its cash, cash equivalents, and investments at certain accredited financial institutions in amounts that exceed federally insured limits. The Company generally invests its excess capital in money market funds, U.S. treasury bonds, U.S. treasury bills, and agency bonds, all of which are subject to minimal credit and market risk. Management has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The investment portfolio is maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards, and limits the credit exposure of any single issuer. The Company is dependent on third-party suppliers for research and development activities of its programs, including preclinical and clinical testing. In particular, the Company relies and expects to continue to rely on a small number of these suppliers, including D. E. Shaw Research, LLC, as discussed in Note 12, Commitments and Contingencies , to meet its requirements for certain of its programs. These programs could be adversely affected by a significant interruption in preclinical and clinical testing, as well as the supply of active pharmaceutical ingredients and formulated drugs. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies, and similar techniques. Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the useful life of the asset. Laboratory and computer equipment are depreciated over three years . Furniture and fixtures are depreciated over five years . Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the underlying asset. Expenditures for repairs and maintenance of assets are charged to expense as incurred. Upon retirement or sale, the cost and related accumulated depreciation of assets disposed of are removed from the accounts and any resulting gain or loss is included in loss from operations. Impairment of Long-Lived Assets The Company continually evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book values of the assets to the expected future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured in an amount by which the book values of the assets exceed their fair value. The Company did no t recognize any impairment losses for the years ended December 31, 2023, 2022, and 2021 . Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include salaries, stock compensation and benefits of employees, third-party license fees, and other operational costs related to the Company’s research and development activities, including allocated facility-related expenses and external costs of outside vendors engaged to conduct both preclinical studies and clinical trials. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses. Stock Compensation For stock options and restricted stock units ("RSUs") granted to employees, directors, and other consultants with vesting over specified periods of continued service, the Company measures their fair value on the grant date using (a) the Black-Scholes Option Pricing Model for stock options and (b) the Company’s closing stock price on such date for RSUs. In connection therewith, compensation expense for such awards is recognized under the straight-line method over the requisite service period, which is generally the vesting period. The Company recognizes the impact of forfeitures on compensation expense as they occur. For stock options and RSUs granted to employees, directors, and other consultants with vesting over specified periods of continued service and contingent upon achievement of certain performance conditions, the Company measures their fair value on the grant date using (a) the Black-Scholes Option Pricing Model for stock options and (b) the Company’s closing stock price on such date for RSUs. In connection therewith, compensation expense for such awards is recognized under the accelerated attribution method over the requisite service period, which is generally the vesting period. The Company recognizes the impact of forfeitures on compensation expense as they occur. During the year ended December 31, 2023 , the Company granted stock options and RSUs to certain employees, with vesting over specified periods of continued service and contingent upon achievement of certain market conditions. The Company measured the fair value of such awards on the grant date using a Monte Carlo Simulation, incorporating various option pricing inputs. In connection therewith, compensation expense for such awards is recognized under the accelerated attribution method over the requisite service period, regardless of whether the market conditions have been achieved. The Company recognizes the impact of forfeitures from market-based awards on compensation expense as they occur. Revenue Recognition The Company accounts for revenue recognition in accordance with ASC 606, pursuant to which an entity recognizes revenue when its customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with customer(s); (ii) identify the performance obligation(s) in the contract(s); (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract(s); and (v) recognize revenue when (or as) the entity satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within the contract and determines those that are performance obligations. The Company then determines the transaction price and allocates it to the performance obligations. As part of the accounting for such arrangements, the Company must use judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above, including the determination of whether milestones or other variable consideration should be included in the transaction price; and (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company utilizes key assumptions and judgments in (a) determining the stand-alone selling price for each performance obligation, which may include discounted cash flow models, evaluation of comparable transactions, and pricing considered in negotiating the transaction and estimated costs, and (b) determining how the transaction price is allocated amongst the performance obligations. The Company also uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. As part of management’s evaluation of the transaction price, the Company considers numerous factors, including whether the achievement of the milestones is outside of the Company's control, contingent upon the efforts of others, or subject to scientific risks of success. If the Company concludes it is probable that a significant revenue reversal would not occur, the associated milestone payment is included in the transaction price. Milestone payments that are not within the Company's control, such as regulatory approvals, are generally not considered probable until those milestones are achieved. The Company re-evaluates the transaction price, including estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as uncertain events are resolved or other changes in circumstances occur. For revenue-based royalties, including milestone payments based on the level of sales, the Company will include royalties in the transaction price at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty is allocated has been satisfied (or partially satisfied). Once the performance obligations are identified, the transaction price is allocated to each performance obligation based on the relative stand-alone selling price. The Company then recognizes as revenue the amount of the transaction price allocated to the respective performance obligation when (or as) it is satisfied, either at a point in time or over time. If the performance obligation is satisfied over time, the Company recognizes revenue based on the use of either an output or input method. Collaboration Agreements The Company enters into collaborative agreements with third parties to research, develop, and commercialize drug candidates, pursuant to which the risks and rewards for such activities are shared between the parties. Such arrangements also provide for cost sharing between the parties during the research and development phase, as well as potential future profit share payments during the commercialization phase. In general, such contracts are evaluated under the provisions of FASB ASC 808, Collaborative Arrangements ("ASC 808"). The amounts receivable and payable for research and development activities are presented net within research and development expense on the consolidated statements of operations and comprehensive loss. As such, the net costs reflect the Company’s share of the ongoing research and development efforts. The amounts receivable and payable for commercialization activities are presented net as either collaboration revenue, separate from revenue from contracts with customers, or collaboration expense on the consolidated statements of operations, as appropriate. Research and Manufacturing Contracts The Company has entered into various research and development contracts with research institutions and other companies whose costs are included in research and development expense in the accompanying consolidated statements of operations and comprehensive loss. These agreements are generally cancelable and related payments are recorded as research and development expenses as the underlying services are performed. When evaluating the adequacy of the expense recognized, the Company analyzes progress of the services, including the phase or completion of events, invoices received, and contracted costs. Judgments and estimates are made in determining the expense recognized and the related prepaid or accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical estimates have not been materially different from the actual costs. Lease Agreements Pursuant to ASC 842, Leases , the Company determines if an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company does not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on its consolidated balance sheets as other noncurrent assets, other current liabilities, and other noncurrent liabilities. The Company does not have any finance leases. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. Operating lease right-of-use assets also include the effect of any lease payments made prior to commencement and exclude lease incentives. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. The Company has lease agreements with lease and non-lease components, which are accounted for as a combined element. Acquired In-Process Research and Development In an asset acquisition, the cost allocated to acquire in-process research and development ("IPR&D") with no alternative future use is charged to expense at the acquisition date. Please refer to Note 10, Acquisition of ZebiAI , for a more detailed description of the accounting policies applied to the Company's only asset acquisition during the three years ended December 31, 2023 . Comprehensive Loss Comprehensive loss includes net loss, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2023, 2022, and 2021 , other comprehensive income (loss) consisted of changes in unrealized gains and losses from available-for-sale investments. Net Loss per Common Share Basic net loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed using the sum of the weighted-average number of common shares outstanding during the period and the effect of any dilutive securities. For periods in which the Company reports a net loss, diluted net loss per share is the same as basic net loss per share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. For additional discussion of net loss per common share, please refer to Note 9, Net Loss per Share. Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts and the tax bases of the assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Recently Adopted Accounting Pronouncements As noted above, the Company adopted ASU 2016-13, as well as the related amendments thereto, on January 1, 2022. The adoption of ASU 2016-13, as well as the related amendments thereto, did not have a material impact on the Company’s consolidated financial statements or disclosures. Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which is intended to provide enhancements to segment disclosures, even for entities with only one reportable segment. In particular, the standard will require disclosures of significant segment expenses regularly provided to the chief operating decision maker and included within each reported measure of segment profit and loss. The standard will also require disclosure of all other segment items by reportable segment and a description of its composition. Finally, the standard will require disclosure of the title and position of the chief operating decision maker and an explanation of how the chief operating decision maker uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. The standard is effective for annual periods beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of the standard on the presentation of its consolidated financial statements and footnotes. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which is intended to provide enhancements to annual income tax disclosures. In particular, the standard will require more detailed information in the income tax rate reconciliation, as well as the disclosure of income taxes paid disaggregated by jurisdiction, among other enhancements. The standard is effective for years beginning after December 15, 2024 and early adoption is permitted. The Company is currently evaluating the impact of the standard on the presentation of its consolidated financial statements and footnotes.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total (in thousands) Assets Cash equivalents: Money market funds $ 140,466 $ — $ — $ 140,466 Total cash equivalents 140,466 — — 140,466 Investments: U.S. treasury bills — 416,008 — 416,008 U.S. agency securities — 190,342 — 190,342 Total investments — 606,350 — 606,350 Total assets $ 140,466 $ 606,350 $ — $ 746,816 Liabilities Contingent Milestone Payments $ — $ — $ 8,206 $ 8,206 Total liabilities $ — $ — $ 8,206 $ 8,206 Fair Value Measurements as of Level 1 Level 2 Level 3 Total (in thousands) Assets Cash equivalents: Money market funds $ 118,446 $ — $ — $ 118,446 U.S. treasury bills — 9,950 — 9,950 Total cash equivalents 118,446 9,950 — 128,396 Investments: U.S. treasury bills — 466,603 — 466,603 U.S. agency securities — 380,520 — 380,520 Total investments — 847,123 — 847,123 Total assets $ 118,446 $ 857,073 $ — $ 975,519 Liabilities Contingent Milestone Payments $ — $ — $ 27,378 $ 27,378 Total liabilities $ — $ — $ 27,378 $ 27,378 In determining the fair value of its investments at each date presented above, the Company relied on quoted prices for similar securities in active markets or using other inputs that are observable or can be corroborated by observable market data. Fair Value of Contingent Consideration In April 2021, the Company acquired ZebiAI, as detailed further in Note 10, Acquisition of ZebiAI . The Company’s Level 3 contingent consideration liability is related to $ 85.0 million of platform and program milestones ("Contingent Milestone Payments") payable to ZebiAI’s former equity holders upon achievement. The contingent consideration liability for the Contingent Milestone Payments is measured at fair value at each reporting date pursuant to FASB ASC Topic 480, Distinguishing Liabilities from Equity ("ASC 480"). The Company determines the fair value of the Contingent Milestone Payments based on the probability of achieving the milestones, the related timing, and, to a lesser extent, an appropriate discount rate. Significant judgment is used in determining the underlying assumptions. Due to the uncertainties associated with the development of platforms and drug candidates in the pharmaceutical industry and the effects of changes in assumptions, including probability of success and related timing, the Company expects its estimates regarding the fair value of Contingent Milestone Payments to continue to change, resulting in adjustments to the fair value of the Company’s Contingent Milestone Payments. The effect of any such adjustments could be material through the date on which the milestones must either be achieved or contractually expire. The Company also has a contingent consideration liability related to the fair value of $ 100.0 million in earnout payments ("Contingent Earnout Payments"). Because the Contingent Earnout Payments were not accounted for as derivatives under FASB ASC Topic 815, Derivatives and Hedging ("ASC 815"), they were only measured at fair value as of the acquisition date and are not re-assessed at fair value at each reporting period. The Contingent Earnout Payments will be adjusted when the contingency is resolved and the consideration is pai d or becomes payable. The following table reconciles the change in the contingent consideration liability: Year Ended December 31, 2023 2022 2021 (in thousands) Balance at beginning of period $ 32,378 $ 50,258 $ — Fair value of contingent consideration upon acquisition — — 47,422 Change in fair value of Contingent Milestone Payments ( 6,422 ) ( 11,677 ) 2,836 Common stock issued upon milestone achievement ( 12,750 ) ( 6,203 ) — $ 13,206 $ 32,378 $ 50,258 The outstanding Contingent Milestone Payments are payable in shares of the Company's common stock based on a fixed amount assigned to each milestone and the volume weighted-average closing price of the Company’s common stock for a specified period prior to the milestone achievement. Accordingly, the number of shares of common stock to be issued upon a milestone achievement varies dependent on the Company’s common stock price. If the outstanding milestones were achieved in full on December 31, 2023 , the number of shares of common stock to be issued would have been 5,272,112 based on a volume weighted-average closing price of the Company's common stock of $ 11.29 for a specified period prior to December 31, 2023 .

Investments

Investments	12 Months Ended
Investments	Dec. 31, 2023
Schedule of Investments [Abstract]
Investments	4. Investments The following tables present the fair value of available-for-sale investments by type of security: December 31, 2023 Amortized Unrealized Unrealized Fair (in thousands) Investments: U.S. treasury bills $ 314,957 $ 83 $ ( 482 ) $ 314,558 U.S. agency securities 185,672 24 ( 353 ) 185,343 Total investments with a maturity of one year or less 500,629 107 ( 835 ) 499,901 U.S. treasury bills 100,917 591 ( 58 ) 101,450 U.S. agency securities 5,000 — ( 1 ) 4,999 Total investments with a maturity of one to two years 105,917 591 ( 59 ) 106,449 Total investments $ 606,546 $ 698 $ ( 894 ) $ 606,350 December 31, 2022 Amortized Unrealized Unrealized Fair (in thousands) Investments: U.S. treasury bills $ 356,728 $ 9 $ ( 5,523 ) $ 351,214 U.S. agency securities 236,483 49 ( 3,104 ) 233,428 Total investments with a maturity of one year or less 593,211 58 ( 8,627 ) 584,642 U.S. treasury bills 116,290 14 ( 915 ) 115,389 U.S. agency securities 148,042 36 ( 986 ) 147,092 Total investments with a maturity of one to two years 264,332 50 ( 1,901 ) 262,481 Total investments $ 857,543 $ 108 $ ( 10,528 ) $ 847,123 The following tables summarize the Company's available-for-sale debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by major security type and length of time in a continuous unrealized loss position: December 31, 2023 Less than 12 Months 12 Months or Longer Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (in thousands) U.S. treasury bills $ 172,625 $ ( 371 ) $ 27,822 $ ( 169 ) $ 200,447 $ ( 540 ) U.S. agency securities 136,356 ( 207 ) 36,742 ( 147 ) 173,098 ( 354 ) Total $ 308,981 $ ( 578 ) $ 64,564 $ ( 316 ) $ 373,545 $ ( 894 ) December 31, 2022 Less than 12 Months 12 Months or Longer Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (in thousands) U.S. treasury bills $ 143,089 $ ( 1,860 ) $ 275,445 $ ( 4,578 ) $ 418,534 $ ( 6,438 ) U.S. agency securities 190,468 ( 1,649 ) 97,305 ( 2,441 ) 287,773 ( 4,090 ) Total $ 333,557 $ ( 3,509 ) $ 372,750 $ ( 7,019 ) $ 706,307 $ ( 10,528 ) As summarized in the tables immediately above, the Company held 70 and 126 debt securities that were in an unrealized loss position as of December 31, 2023 and 2022, respectively. The unrealized losses at December 31, 2023 and 2022 were attributable to changes in interest rates and the unrealized losses do not represent credit losses. The Company does not intend to sell these securities and it is not more likely than not that it will be required to sell them before recovery of their amortized cost basis.

Property and Equipment

Property and Equipment	12 Months Ended
Property and Equipment	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	5. Property and Equipment Property and equipment, net consisted of the following: December 31, 2023 2022 (in thousands) Property and equipment: Laboratory equipment $ 25,558 $ 21,472 Leasehold improvements 3,826 3,826 Computer equipment 1,743 1,743 Furniture and fixtures 1,779 1,762 Construction in process 1,577 1,220 34,483 30,023 Less: accumulated depreciation ( 23,582 ) ( 18,389 ) Total property and equipment, net $ 10,901 $ 11,634 The Company recorded $ 5.3 million, $ 4.1 million, and $ 3.9 million of depreciation expense for the years ended December 31, 2023, 2022, and 2021 , respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
Accrued Expenses	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following: December 31, 2023 2022 (in thousands) External research and development costs $ 12,509 $ 19,276 Consulting and professional services 886 831 Compensation costs 702 1,043 Other 793 1,553 Total accrued expenses $ 14,890 $ 22,703

Common Stock

Common Stock	12 Months Ended
Common Stock	Dec. 31, 2023
Stockholders' Equity Note [Abstract]
Common Stock	7. Common Stock Each share of common stock entitles the stockholder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Company’s board of directors. As of December 31, 2023 , no dividends had been declared. Restricted Common Stock In prior years, the Company issued restricted shares of common stock to its founders and consultants. The Company also issued restricted shares of common stock upon the early exercise of stock options under the Company’s 2016 Stock Option and Grant Plan (the "2016 Stock Plan"). The restrictions on the common shares generally lapsed over vesting terms of four years . The Company included the proceeds from the issuance of the restricted shares of common stock as a restricted stock liability on the accompanying consolidated balance sheets. Amounts were reclassified to additional paid-in capital as the restrictions lapsed. The Company had the right to repurchase any unvested shares of restricted common stock at the original cost upon termination. As of December 31, 2021, the restrictions had lapsed on each share of restricted common stock issued in prior years. At-the-Market Offerings In August 2021, the Company entered into a sales agreement, (the "Sales Agreement"), with Cowen and Company, LLC ("Cowen"), pursuant to which the Company may offer and sell shares of its common stock having aggregate gross proceeds of up to $ 300.0 million from time to time in "at-the-market" offerings through Cowen, as the Company’s sales agent ("At-the-Market Offerings"). As of December 31, 2022 , no shares of common stock had been sold via At-the-Market Offerings under the Sales Agreement. During the year ended December 31, 2023 , the Company sold 3,026,072 shares of common stock via At-the-Market Offerings under the Sales Agreement at a weighted-average average price of $ 10.26 per share. The Company received proceeds of $ 30.3 million, which was net of $ 0.8 million in commissions paid to Cowen and other offering expenses. Follow-On Offerings In October 2021, the Company completed a public offering of 15,188,679 shares of common stock, including the exercise in full of the underwriters’ option to purchase an additional 1,981,132 shares, at an offering price of $ 26.50 per share. The Company received proceeds of $ 382.2 million, which was net of $ 20.3 million in underwriting discounts and commissions, as well as other offering expenses. In September 2022, the Company completed a public offering of 11,320,755 shares of common stock at an offering price of $ 26.50 per share. The Company received proceeds of $ 284.7 million, which was net of $ 15.3 million in underwriting discounts and commissions, as well as other offering expenses. Private Placement In January 2024, the Company entered into a securities purchase agreement with Nextech Crossover I SCP for the private placement of 2,500,000 shares of common stock at $ 12.00 per share (the "Private Placement"). The aggregate gross proceeds for the Private Placement were approximately $ 30.0 million, before deducting offering expenses payable by the Company in 2024.

Stock Compensation

Stock Compensation	12 Months Ended
Stock Compensation	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock Compensation	8. Stock Compensation In 2016, the Company adopted the 2016 Stock Plan. Subsequent to July 2020, no further awards have been granted under the 2016 Stock Plan and all equity-based awards have been and will continue to be granted under the 2020 Stock Option and Incentive Plan (the "2020 Stock Plan"). To the extent outstanding options granted under the 2016 Stock Plan are cancelled, forfeited, or otherwise terminated without being exercised and would otherwise have been returned to the share reserve under the 2016 Stock Plan, the number of shares underlying such awards will be available for future grant under the 2020 Stock Plan. In 2020, the Company’s stockholders approved the 2020 Stock Plan. All of the Company’s employees, officers, directors, and consultants are eligible to be granted options, restricted stock units, and other stock-based awards under the terms of the 2020 Stock Plan, which originally provided for the issuance of up to 8,376,080 of stock-based awards. The 2020 Stock Plan is also subject to annual increases to be added on the first day of each fiscal year, commencing on January 1, 2021, equal to 5 % of the number of outstanding shares on the immediately preceding December 31 or such lesser number of shares approved by the Company’s board of directors or compensation committee of the board of directors. On January 1, 2023, the number of shares available for issuance under the 2020 Stock Plan was increased by 6,056,111 shares of common stock. There were 9,160,736 stock-based awards available for grant at December 31, 2023 under the 2020 Stock Plan. In 2020, the Company adopted an Employee Stock Purchase Plan ("ESPP") that permits eligible employees to enroll in six-month offering periods. Participants may purchase shares of the Company’s common stock, through after-tax payroll deductions, at a price equal to 85 % of the fair market value of the common stock on the first or last day of the applicable six-month offering period, whichever is lower. Purchase dates under the ESPP occur on or about June 30 and December 31 each year, with the initial purchase date under the ESPP on December 31, 2021. The Company’s stockholders originally authorized 1,092,532 shares for issuance pursuant to the ESPP, which is subject to annual increases to be added on the first day of each fiscal year, commencing on January 1, 2021, equal to the lesser of 2,185,064 shares of the Company’s common stock, 1 % of the number of outstanding shares on the immediately preceding December 31, or an amount determined by the Company’s board of directors. On January 1, 2023, the number of shares available for issuance under the ESPP was increased by 1,211,222 shares of common stock. There were 3,874,096 shares available for grant at December 31, 2023 under the ESPP. In connection with all stock-based payments, total stock compensation expense recognized was as follows: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 48,351 $ 30,671 $ 24,922 General and administrative expenses 37,680 25,467 23,532 $ 86,031 $ 56,138 $ 48,454 Time-Based Stock Options The Company has historically granted stock options to employees, directors, and consultants with vesting conditions based on continued service over time. Accordingly, stock compensation expense for such awards is recognized using a straight-line attribution model over the vesting term of each option. The following table summarizes activity for time-based stock options under the 2016 Stock Plan and the 2020 Stock Plan for the year ended December 31, 2023: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2022 9,276,552 $ 18.33 7.85 $ 34,647 Granted 4,129,710 18.64 Exercised ( 366,025 ) 4.95 Cancelled ( 648,422 ) 23.52 Outstanding at December 31, 2023 12,391,815 $ 18.56 7.58 $ 18,907 Vested at December 31, 2023 6,651,356 $ 16.57 6.68 $ 18,559 Unvested at December 31, 2023 5,740,459 $ 20.87 8.62 $ 348 The total intrinsic value of time-based stock options exercised was $ 4.4 million, $ 15.5 million, and $ 32.4 million for the years ended December 31, 2023, 2022, and 2021, respectively. The fair value of each time-based stock option granted is estimated on the date of grant using the Black-Scholes option pricing model, pursuant to which the weighted-average grant date fair values were $ 12.83 , $ 13.67 , and $ 22.95 during the years ended December 31, 2023, 2022, and 2021 , respectively. The following table summarizes the assumptions used in calculating the fair value of the time-based stock options granted. Year Ended December 31, 2023 2022 2021 Expected term (in years) 6.25 6.25 6.25 Risk-free interest rate 3.3 % to 5.0 % 1.6 % to 4.2 % 0.6 % to 1.6 % Expected volatility 74.1 % to 79.8 % 72.7 % to 76.2 % 74.7 % to 76.6 % Expected dividend yield 0.0 % 0.0 % 0.0 % The Company uses the simplified method to calculate the expected term, as it does not have sufficient historical exercise data as a public company to provide a reasonable basis upon which to estimate the expected term for time-based stock options granted. The expected term is applied to the time-based stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among the Company’s employees, directors, and consultants. The risk-free interest rate is based on a U.S. treasury instrument, whose term is consistent with the expected term of the time-based stock options. The Company’s stock price volatility assumption is based on historical volatility of a group of peer companies with similar characteristics to the Company and who have similar risk profiles and positions within the industry. The Company accounts for forfeitures as they occur. As of December 31, 2023 , the total unrecognized stock compensation related to unvested time-based stock options was $ 73.1 million, which the Company expects to recognize over a weighted-average period of approximately 1.35 years. Performance-Based Stock Options In March 2020 and September 2021, the Company granted options to certain employees with performance-based vesting conditions under the 2016 Stock Plan and 2020 Stock Plan. In both instances, the commencement of vesting is based on the achievement of various scientific and operational milestones during specified periods, subject to the discretion and approval of either the Company’s board of directors or President and Chief Executive Officer. For the performance-based stock options, the Company applies variable accounting until the performance criteria are determined to be achieved, at which time vesting commences over contractual service periods. Furthermore, because (a) the awards were authorized prior to the accounting grant date in the context of ASC 718, Stock Compensation , (b) the recipients were providing service prior to the accounting grant date, and (c) there were performance conditions that, if not met by the accounting grant date, would have resulted in the forfeiture of the award, the service inception dates preceded the accounting grant dates. Ultimately, the stock compensation expense for the options is determined based on the fair value of the awards on the accounting grant dates, which is then recognized using an accelerated attribution model over the vesting term commencing upon the actual or expected accounting grant dates. For the performance-based stock options granted in March 2020 and September 2021, all performance conditions were resolved in prior periods and the grant dates were set at or prior to December 31, 2023 The following table summarizes activity for performance-based stock options for the year ended December 31, 2023: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2022 1,774,183 $ 5.41 7.18 $ 17,128 Exercised ( 33,473 ) 5.22 Cancelled ( 34,759 ) 5.22 Outstanding at December 31, 2023 1,705,951 $ 5.42 6.18 $ 9,808 Vested at December 31, 2023 1,330,460 $ 5.27 6.17 $ 7,691 Unvested at December 31, 2023 375,491 $ 5.96 6.21 $ 2,117 The total intrinsic value of performance-based stock options exercised was $ 0.3 million, $ 0.4 million, and $ 1.1 million, for the years ended December 31, 2023, 2022, and 2021, respectively. The fair value of each performance-based stock option granted is estimated on the accounting grant date, or at the end of each reporting period if variable accounting is applied, using the Black-Scholes option-pricing model, pursuant to which the grant date fair value was $ 20.28 for performance-based stock options granted during the year ended December 31, 2021 . There were no performance-based stock options granted during the years ended December 31, 2023 and 2022. The assumptions and methodologies used in calculating the fair value of performance-based stock options granted during the year ended December 31, 2021 was similar to the assumptions and methodologies used in calculating the fair value of time-based stock options granted during the year ended December 31, 2021. As of December 31, 2023 , the total unrecognized stock compensation related to unvested performance-based stock options was $ 1.9 million, which the Company expects to recognize over a weighted-average period of approximately 0.48 years. RSUs Starting in 2021, the Company has granted RSUs to employees, directors, and consultants under the 2020 Stock Plan. Each of the RSUs represents the right to receive one share of the Company’s common stock upon vesting. The majority of RSUs granted to date have vesting conditions based on continued service over time. Accordingly, stock compensation expense for the majority of such awards is recognized using a straight-line attribution model over the vesting term of each RSU. The fair value of each RSU is based on the closing price of the Company’s common stock on the date of grant. The following table summarizes activity for RSUs under the 2020 Stock Plan for the year ended December 31, 2023: Number of Shares Underlying RSUs Weighted-Average Unvested at December 31, 2022 1,566,760 $ 24.62 Granted 2,591,453 17.74 Vested ( 883,652 ) 21.50 Cancelled ( 282,314 ) 24.00 Unvested at December 31, 2023 2,992,247 19.14 The fair value of RSUs that vested during the year ended December 31, 2023 was $ 10.5 million. As of December 31, 2023 , the total unrecognized compensation related to unvested RSUs granted was $ 51.3 million, which the Company expects to recognize over a weighted-average period of approximately 1.41 years. Market-Based Awards During the year ended December 31, 2023 , the Company granted 1,512,820 stock options and 405,770 RSUs under the 2020 Stock Plan to certain employees, with vesting over three years of continued service and contingent upon achievement of certain market conditions ("2023 Market-Based Awards"). The Company measured the fair value of the 2023 Market-Based Awards on the grant date using a Monte Carlo Simulation, incorporating various option pricing inputs, including (a) the contractual term, or 10.0 years, (b) exercise price for the stock options and stock price on the grant date for the RSUs, or $ 20.45 , (c) estimated expected term, or 6.5 years, (d) risk-free interest rate, or 3.5 %, (e) historical volatility, or 75.0 %, and (f) dividend yield, or 0.0 %. Ultimately, the fair value of the 2023 Market-Based Awards was estimated as $ 12.53 per share for the stock options and $ 16.11 per share for the RSUs, yielding a total of $ 25.5 million. The total compensation expense, or $ 25.5 million, is being recognized pursuant to the accelerated attribution method over the requisite service period of three years , regardless of whether the market conditions have been achieved. The impact of forfeitures, if any, will be recognized upon occurrence. As of December 31, 2023, the market conditions underlying the 2023 Market-Based Awards had not been achieved. During the year ended December 31, 2023 , none of the 2023 Market-Based Awards vested and, therefore, none of the options were exercised and none of the RSUs were released. There were also no cancellations of the 2023 Market-Based Awards through December 31, 2023 As of December 31, 2023 , the total unrecognized compensation related to unvested market-based awards granted was $ 9.0 million, which the Company expects to recognize over a period of 2.07 years. Employee Stock Purchase Plan The following table summarizes activity under the Company's ESPP from the initial offering period, or July 1, 2021 through December 31, 2023, including (a) after-tax contributions from employees, (b) shares purchased, and (c) weighted-average assumptions used in the Black-Scholes option pricing model to estimate the fair value of the option component of the shares purchased under the ESPP in each period. Year Ended December 31, 2023 2022 2021 After-tax contributions (in thousands) $ 2,486 $ 1,686 $ 1,141 Shares of common stock purchased 244,125 123,019 43,685 Expected term (in years) 0.50 0.50 0.50 Risk-free interest rate 5.0 % 1.0 % 0.1 % Expected volatility 86.8 % 74.4 % 65.1 % Expected dividend yield 0.0 % 0.0 % 0.0 % As of December 31, 2023 , there was no unrecognized stock compensation expense related to ESPP, since the purchase for the offering period between July 1, 2023 and December 31, 2023 was transacted on December 31, 2023 .

Net Loss Per Share

Net Loss Per Share	12 Months Ended
Net Loss Per Share	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net Loss per Share The following table summarizes the computation of basic and diluted net loss per share of the Company: Year Ended December 31, 2023 2022 2021 (in thousands, except share and per share data) Net loss $ ( 341,973 ) $ ( 290,509 ) $ ( 363,872 ) Net loss per share, basic and diluted $ ( 2.79 ) $ ( 2.59 ) $ ( 3.82 ) Weighted average shares of common stock, basic and diluted 122,576,527 112,233,649 95,136,719 For the years ended December 31, 2023, 2022, and 2021, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same. In computing diluted net loss per share for the years ended December 31, 2023, 2022, and 2021, the Company excluded the following potentially dilutive securities, as the effect would be anti-dilutive and reduce the net loss per share calculated for each period. Year Ended December 31, 2023 2022 2021 Options outstanding to purchase common stock 15,610,586 11,050,735 8,719,627 Unvested and outstanding restricted stock units 3,398,017 1,566,760 691,205 Common stock issued upon milestone achievement 1,535,404 201,569 — 20,544,007 12,819,064 9,410,832 The amounts included in the table above for options and RSUs are presented based on amounts outstanding at each period end. The amounts included in the table above for common stock issued upon milestone achievement are presented based on the weighted-average anti-dilutive effect from shares issued in connection with Contingent Milestone Payments in each of the periods presented.

Acquisition of ZebiAI

Acquisition of ZebiAI	12 Months Ended
Acquisition of ZebiAI	Dec. 31, 2023
Business Combination, Description [Abstract]
Acquisition of ZebiAI	10. Acquisition of ZebiAI On April 22, 2021 (the "Acquisition Date"), the Company acquired ZebiAI, a privately held company focused on using machine learning combined with DNA encoded library data sets for drug discovery. Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), upfront consideration included (a) payment of approximately $ 20.0 million in cash and (b) issuance of 1,914,219 shares of the Company’s common stock at an aggregate fair value of $ 61.8 million, both transferred to ZebiAI’s former stockholders, option holders, and warrant holders (the "ZebiAI Holders") upon closing. In addition, (i) the ZebiAI Holders are eligible to receive up to $ 85.0 million in other payments upon the achievement of certain platform or program milestones within a specified period from the closing date of the Merger Agreement, payable in shares of the Company's common stock (the "Contingent Milestone Payments"), a portion of which was paid to the ZebiAI Holders in 2022 and 2023 , and (ii) the Company will pay 10 % of payments it receives within a specified period from the closing date of the Merger Agreement from partnering, collaboration, or other agreements related to ZebiAI’s platform, up to an aggregate maximum amount of $ 100.0 million, payable in cash (the "Contingent Earnout Payments"), to the ZebiAI Holders. In accounting for the transaction, the Company assessed if ZebiAI represented an asset or business under ASC 805, Business Combinations ("ASC 805"), as amended by ASU 2017-01. Pursuant to the guidance noted, the Company concluded ZebiAI did not constitute a business, since substantially all of the fair value of the gross assets acquired was concentrated in a single asset, which was the intellectual property for the AI platform and the related data sets in development by ZebiAI. The intellectual property acquired from ZebiAI was at an early stage of development and continues to require a significant investment of time and capital for development. There is no assurance the Company will be successful in completing the additional research and development activities. The Company also concluded the acquisition represented an initial consolidation of a variable interest entity that does not constitute a business in accordance with ASC 810, Consolidation ("ASC 810"). In connection therewith, the Company determined ZebiAI was considered to be a variable interest entity, as it did not have sufficient equity to finance its activities without additional subordinated financial support. Prior to the Acquisition Date, the primary source of funding for ZebiAl had been preferred stock financings and convertible notes. The Company acquired all of the outstanding shares of ZebiAI and, therefore, is the sole equity holder. The Company will absorb the losses of ZebiAI, has the rights to the benefits derived from the ZebiAI platform, and the power to direct all activities. Therefore, the Company is the primary beneficiary. The net assets acquired and liabilities assumed in connection with the acquisition were recorded at their estimated fair values as of the Acquisition Date. Total consideration transferred of $ 135.5 million included the cash and shares of the Company's common stock issued to ZebiAI Holders, the fair value of the Contingent Milestone Payments, and the fair value of the Contingent Earnout Payments, as well as an insignificant amount attributed to the replacement of stock options to ZebiAI Holders. The Contingent Milestone Payments were determined to be liabilities pursuant to ASC 480 and, therefore, included in consideration transferred. The Contingent Earnout Payments were required to be included in total consideration transferred as a result of the guidance under ASC 810. The difference between total consideration transferred and the fair value of net assets acquired and liabilities assumed of $ 11.9 million was recorded as loss on initial consolidation of a variable interest entity pursuant to ASC 810. The following table summarizes net assets acquired based on their estimated fair values as of the Acquisition Date: Amount (in thousands) Acquired IPR&D asset $ 123,000 Loss on initial consolidation of VIE 11,855 Assets obtained in asset acquisition 662 Liabilities assumed in asset acquisition ( 2,330 ) Intangible asset 2,300 Net acquired assets $ 135,487 In estimating the fair value of the acquired tangible assets and liabilities assumed, the Company used the carrying value of the net working capital balances as the most reliable indicator of fair value based on the associated short-term nature of the balances. The remaining fair value was attributable to the acquired IPR&D and an intangible asset. The fair value attributable to the IPR&D asset was determined using an Avoided Cost Method, which includes all costs to develop the IPR&D asset, including appropriate mark-ups on the cost estimate and an expected return related to developing the IPR&D asset over a period of time. The fair value of the IPR&D asset was expensed in the Company’s consolidated statements of operations and comprehensive loss for the year ended December 31, 2021, as the acquired IPR&D had no alternative future use, which was determined by the Company in accordance with U.S. GAAP, including ASC 730, Research and Development ("ASC 730"). The intangible asset represents the assembled workforce, for which the Company concluded there were no indicators of impairment through December 31, 2023 . The Company recognized stock compensation expense of $ 4.6 million associated with accelerated vesting for certain stock options in connection with the acquisition within the consolidated statements of operations and comprehensive loss for the year ended December 31, 2021 , with no incremental charges in connection therewith for the years ended December 31, 2023 and 2022 . Finally, the Company recognized other acquisition costs of $ 0.9 million within general and administrative expenses in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2021 , with no incremental charges in connection therewith for the years ended December 31, 2023 and 2022. For the Contingent Milestone Payments and Contingent Earnout Payments, the Company recorded contingent consideration liabilities of $ 42.4 million and $ 5.0 million, respectively, representing the fair value of the payment provisions noted as of the Acquisition Date. The Company is required to re-assess the fair value of the Contingent Milestone Payments at each reporting period pursuant to ASC 480, as summarized within Note 3, Fair Value Measurements . However, the Contingent Earnout Payments were not accounted for as derivatives under ASC 815 and, therefore, are not re-assessed at fair value at each reporting period. The Contingent Earnout Payments will be adjusted when the contingency is resolved and the consideration is paid or becomes payable.

Collaboration and License Arran

Collaboration and License Arrangements	12 Months Ended
Collaboration and License Arrangements	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreement with Genentech, Inc.	11. Collaboration and License Agreement with Genentech, Inc. Summary of Terms In December 2020, the C ompany and Genentech, Inc. ("Genentech") entered into the Collaboration and License Agreement (as amended from time to time, the "Genentech Agreement"), which granted Genentech a license to develop and commercialize GDC-1971 (migoprotafib, formerly known as RLY-1971). Under the terms of the Genentech Agreement, the Company had the option, exercisable one time at the Company’s sole discretion, to share half of the net profits or net losses of commercializing migoprotafib in the U.S., subject to certain terms and conditions (such option, the "Opt-In Right"). During the year ended December 31, 2023, the Company elected to not exercise the Opt-In Right. As of December 31, 2023 , consideration under the Genentech Agreement included (a) $ 86.8 million in non-refundable payments ("Genentech Non-Refundable Payments") and (b) $ 25.0 million in payments upon achievement of certain milestones, which were refundable if the Company had exercised the Opt-In Right ("Genentech Milestones Paid"). In February 2024, the Company received an additional payment of $ 10.0 million in connection with a milestone achievement occurring after December 31, 2023 . The Company is eligible to receive up to an aggregate of $ 675.0 million in additional payments upon achievement of other specified development, commercialization, and sales-based milestones for migoprotafib worldwide, as well as tiered royalties ranging from low-to-mid teens on annual worldwide net sales of migoprotafib, on a country-by-country basis, subject to reduction in certain circumstances. Due to the nature of the payments noted, such variable consideration was constrained and excluded from the transaction price of the Genentech Agreement as of December 31, 2023. Accounting Analysis Identification of the Contract The Company concluded Genentech is a customer and, as such, the Genentech Agreement is within the scope of the revenue recognition guidance under ASC 606. Identification of Performance Obligations At the commencement of the Genentech Agreement, the Company identified the following performance obligations: • License to develop and commercialize migoprotafib and the related know-how; • Research and development services to complete the Phase 1a Trial for migoprotafib; and • Transfer of active pharmaceutical ingredient and other materials related to migoprotafib. The Company concluded the performance obligations outlined above are both capable of being distinct and distinct within the context of the contract, given such rights and activities are independent of each other. The license can be used by Genentech without the research and development services or active pharmaceutical ingredient outlined above. Similarly, such services and inventory provide distinct benefit to Genentech within the context of the contract, separate from the license. Determination of Transaction Price As of December 31, 2023 , the Company concluded the transaction price for the Genentech Agreement was $ 111.8 million, which includes both the Genentech Non-Refundable Payments and Genentech Milestones Paid. Upon the Company’s election to not exercise the Opt-In Right during the year ended December 31, 2023 , the $ 25.0 million in Genentech Milestones Paid, which had been received by the Company before the year ended December 31, 2023, were removed from other current liabilities on the condensed consolidated balance sheet and incorporated into the transaction price, since the constraint on such variable consideration had been resolved. No other milestone payments are included in the transaction price, as such payments are variable consideration fully constrained as of December 31, 2023. As part of management’s evaluation of the constraint, the Company considered numerous factors, including consideration of the fact that achievement of the milestones is outside of the Company’s control, contingent upon Genentech’s efforts, the receipt of regulatory approval, and subject to scientific risks of success. Allocation of Transaction Price to Performance Obligations The Company allocated the transaction price of $ 111.8 million based on the stand-alone selling prices ("SSP") of each of the performance obligations as follows: • $ 107.6 million for the transfer of the license; • $ 3.8 million for research and development services; and • $ 0.4 million for the transfer of active pharmaceutical ingredient. The SSP for the license was determined using an approach that considered discounted, probability-weighted cash flows related to the license transferred. The Company also reviewed comparable market transactions in determining the SSP of the license. The SSP for the research and development services and the transfer of active pharmaceutical ingredient were based on estimates of the associated effort and cost of these services and cost to manufacture active pharmaceutical ingredient, adjusted for a reasonable profit margin that would be expected to be realized under similar contracts. Recognition of Revenue The Company is recognizing revenue for each of the performance obligations as follows. • Upon execution of the Genentech Agreement in 2020, the license and related know-how were transferred. Therefore, the full amount allocated to the license and related know-how at such time was recognized immediately in 2020. As the transaction price has been updated through December 31, 2023, any changes to the amount allocated to the performance obligation for transfer of the license and related know-how have also been recognized immediately. Revenue recognized related to the performance obligation during the years ended December 31, 2023, 2022, and 2021 was $ 24.0 million, $ 0.3 million, and $ 0.6 million, respectively. • The performance obligation for research and development services consisted of the Company completing the Phase 1a clinical trial initiated in 2020. The Company fully satisfied the performance obligation during the year ended December 31, 2023, recognizing revenue over time using a cost-based input method by calculating actual costs incurred to date at each period end relative to total estimated costs expected to be incurred. Revenue recognized related to the performance obligation during the years ended December 31, 2023, 2022, and 2021 was $ 1.4 million, $ 0.7 million, and $ 1.7 million, respectively. • The amount of the transaction price originally allocated to the performance obligation for active pharmaceutical ingredient was recognized in full upon transfer of such material to Genentech in 2021. As the transaction price has been updated through December 31, 2023, any changes to the amount allocated to the performance obligation for transfer of active pharmaceutical ingredient have also been recognized immediately. Revenue recognized related to the performance obligation during the years ended December 31, 2023, 2022, and 2021 was $ 0.1 million, $ 0.1 million, and $ 0.3 million, respectively. During the years ended December 31, 2023, 2022, and 2021 , the Company recognized an aggregate of $ 25.5 million, $ 1.0 million, and $ 2.6 million, respectively, of revenue from the Genentech Agreement. As of December 31, 2022 , the Company also had recorded a contract asset of $ 4.9 million, which was classified as a current asset on the condensed consolidated balance sheet. The contract asset related to the amount of revenue recognized for which the right to payment was contingent upon conditions besides the passage of time. During the year ended December 31, 2023 , such conditions were satisfied and $ 5.0 million was paid in cash to the Company in June 2023, at which point the contract asset was removed. As of December 31, 2023 , no amounts from such payment are recorded on the condensed consolidated balance sheet.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Intellectual Property License The Company has a Collaboration and License Agreement with D. E. Shaw Research, LLC ("D. E. Shaw Research"), which held 9,999,999 shares of Series A preferred stock and 1,557,875 shares of Series C preferred stock at December 31, 2019. In conjunction with the Company's initial public offering in 2020, such shares were converted into 3,281,253 shares of common stock of the Company. The contract provides that the parties will jointly conduct research efforts with the goal of identifying and developing product candidates. The original term of the contract was three years and required the Company to pay an annual fee of $ 1.0 million. On June 15, 2020, the Company and D. E. Shaw Research agreed to amend the Collaboration and License Agreement (the "DESRES Agreement"). The DESRES Agreement extended the term of the agreement to August 16, 2025 and increased the annual fee from $ 1.0 million to $ 9.9 million. The DESRES Agreement also automatically renews for successive one-year periods, unless either party provides at least one year notice of non-renewal. The annual fee during each of the one-year renewal terms is subject to mutual agreement of the Company and D. E. Shaw Research. The Company is obligated to pay potential development milestone payments under the terms of the DESRES Agreement up to $ 7.3 million per target, plus sales milestones and royalties, upon the achievement of certain specified contingent events. Such payments for achievement of development and regulatory milestones total up to $ 7.3 million in the aggregate for each of the first three products the Company develops and up to $ 6.3 million, in the aggregate, for each product the Company develops after the first three. The Company assessed the milestone and royalty events under the DESRES Agreement as of December 31, 2023 and 2022, concluding no such payments were due. For the years ended December 31, 2023, 2022, and 2021 , the Company recorded research and development expenses of $ 9.5 million, $ 9.4 million, and $ 9.5 million, respectively, under the DESRES Agreement on its consolidated statements of operations and comprehensive loss. As of December 31, 2023 and 2022 , the Company had prepaid balances of $ 5.4 million and $ 4.9 million, respectively, under the DESRES Agreement on its consolidated balance sheets. As of December 31, 2023 and 2022 , the Company had no accrued expense and accounts payable balances under the DESRES Agreement on its consolidated balance sheets. Other Research Arrangements The Company has certain other research and license arrangements and other collaborations with third parties, which provide the Company with specified research and/or development services.

Leases

Leases	12 Months Ended
Leases	Dec. 31, 2023
Leases [Abstract]
Leases	13. Leases 399 Binney Street In December 2017, the Company entered into an operating lease agreement for 44,336 square feet of office and laboratory space at 399 Binney Street, Cambridge, Massachusetts, which was increased to 44,807 square feet in January 2018. The Company gained control of the leased space in January 2019 and, accordingly, recorded an operating lease right-of-use asset and liability at such time. The operating lease expires in April 2029 , subject to certain renewal options, which have not been included in the Company’s operating lease right-of-use asset and liability, as the Company is not reasonably certain to exercise such options as of December 31, 2023. In September 2020, the Company entered into an amendment to its operating lease agreement to expand the leased area by 1,824 square feet of office space at 399 Binney Street, Cambridge, Massachusetts. The amendment to the operating lease agreement met the criteria to be accounted for as a separate operating lease. The Company gained control of the leased space in October 2020 and, accordingly, recorded an operating lease right-of-use asset and liability at such time. The operating lease right-of-use asset and lease liability recorded in connection with the amendment were not material. The amended operating lease expires in April 2029, subject to certain renewal options. As discussed in Note 2, Significant Accounting Policies , the Company provided a letter of credit in the amount of $ 0.9 million with a financial institution, which expires commensurate with the lease in April 2029 . The following table summarizes the presentation of amounts recorded on the Company’s consolidated balance sheets for the operating lease at 399 Binney Street as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 (in thousands) Assets: Operating lease assets $ 16,670 $ 18,828 Liabilities: Operating lease liabilities $ 2,535 $ 2,170 Operating lease liabilities, net of current portion 16,352 18,886 Total operating lease liabilities $ 18,887 $ 21,056 The following table summarizes the effect of lease costs for the Company's operating lease at 399 Binney Street on the Company’s condensed consolidated statements of operations and comprehensive loss for the years ended December 31, 2023, 2022, and 2021: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 3,631 $ 3,350 $ 3,262 General and administrative expenses 614 893 1,002 $ 4,245 $ 4,243 $ 4,264 The Company made cash payments of $ 4.3 million, $ 4.1 million, and $ 4.0 million under the operating lease agreement for 399 Binney Street during the years ended December 31, 2023, 2022, and 2021, respectively. As of December 31, 2023 , t he minimum lease payments for the Company’s operating lease at 399 Binney Street for the next five years and thereafter are expected to be as follows: Year Ending December 31, Amount (in thousands) 2024 4,377 2025 4,503 2026 4,634 2027 4,768 2028 4,906 Thereafter 1,651 Total lease payments 24,839 Less: interest ( 5,952 ) Present value of operating lease liabilities $ 18,887 The weighted-average remaining lease term and weighted-average discount rate of the Company's operating lease at 399 Binney Street were 5.33 years and 10.4 %, respectively, at December 31, 2023. The weighted-average remaining lease term and weighted-average discount rate of the Company's operating lease at 399 Binney Street were 6.33 years and 10.4 %, respectively, at December 31, 2022. 60 Hampshire Street In May 2021, the Company entered into an operating lease agreement for 41,474 square feet of office and laboratory space at 60 Hampshire Street, Cambridge, Massachusetts. The Company gained control of the leased space in July 2022 and, accordingly, recorded an operating lease right-of-use asset and liability at such time. The operating lease expires in June 2032 and there are no renewal options. As discussed in Note 2, Significant Accounting Policies , the Company provided a letter of credit in the amount of $ 1.8 million with a financial institution, which expires commensurate with the lease in June 2032 . The following table summarizes the presentation of amounts recorded on the Company’s consolidated balance sheets for the operating lease at 60 Hampshire Street as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 (in thousands) Assets: Operating lease assets $ 41,299 $ 44,926 Liabilities: Current operating lease liabilities $ 2,429 $ 2,106 Operating lease liabilities, net of current portion 32,150 34,580 Total operating lease liabilities $ 34,579 $ 36,686 The following table summarizes the effect of lease costs for the Company's operating lease at 60 Hampshire Street on the Company’s condensed consolidated statements of operations and comprehensive loss for the years ended December 31, 2023, 2022, and 2021: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 5,549 $ 2,675 $ — General and administrative expenses 938 564 — $ 6,487 $ 3,239 $ — The Company made cash payments of $ 5.0 million, $ 11.5 million, and $ 0 under the operating lease agreement for 60 Hampshire Street during the years ended December 31, 2023, 2022, and 2021, respectively. As of December 31, 2023 , t he minimum lease payments for the Company’s operating lease at 60 Hampshire Street for the next five years and thereafter are expected to be as follows: Year Ending December 31, Amount (in thousands) 2024 5,109 2025 5,257 2026 5,409 2027 5,565 2028 5,726 Thereafter 21,358 Total lease payments 48,424 Less: interest ( 13,845 ) Present value of operating lease liabilities $ 34,579 The weighted-average remaining lease term and weighted-average discount rate of the Company's operating lease at 60 Hampshire Street were 8.50 years and 8.0 %, respectively, at December 31, 2023. The weighted-average remaining lease term and weighted-average discount rate of the Company's operating lease at 60 Hampshire Street were 9.50 years and 8.0 %, respectively, at December 31, 2022 .

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes During the years ended December 31, 2023, 2022, and 2021 , the Company recorded no income tax benefits due to losses incurred and the uncertainty of future taxable income. A reconciliation of the expected income tax (benefit) computed using the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023, 2022, and 2021: December 31, 2023 2022 2021 Income tax computed at federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit ( 3.7 )% 6.5 % 5.7 % Change in valuation allowance ( 20.3 )% ( 30.2 )% ( 20.5 )% IPR&D 0.0 % 0.0 % ( 7.0 )% R&D credit carryovers 4.5 % 4.2 % 2.2 % Stock compensation ( 1.7 )% ( 2.1 )% ( 0.4 )% Permanent differences 0.2 % ( 0.6 )% ( 1.0 )% Total 0.0 % 0.0 % 0.0 % The Company’s deferred tax assets and liabilities at December 31, 2023 and 2022, consist of the following: December 31, 2023 2022 (in thousands) Deferred tax assets: Net operating losses $ 141,453 $ 119,688 Tax credit carryforwards 45,969 30,593 Capitalized R&D 90,273 55,303 Lease liability 12,914 18,307 Stock compensation 19,448 14,510 Intangibles 1,261 1,875 Depreciation and amortization 505 568 Other 263 7,270 Total gross deferred tax assets 312,086 248,114 Valuation allowance ( 299,829 ) ( 230,518 ) Net deferred tax assets 12,257 17,596 Deferred tax liabilities Operating lease assets ( 12,257 ) ( 17,596 ) Total deferred tax liabilities ( 12,257 ) ( 17,596 ) $ — $ — The Company has incurred net operating losses ("NOLs") since inception. As of December 31, 2023 and 2022 , the Company had federal NOL carryforwards of $ 498.0 million and $ 412.1 million, respectively, available to reduce taxable income, of which $ 43.1 million expire beginning in 2035 and $ 454.9 million do not expire. The Company also has state NOL carryforwards of $ 559.7 million and $ 501.7 million as of December 31, 2023 and 2022 , respectively, available to reduce future state taxable income, which expire at various dates beginning in 2035 . As of December 31, 2023 and 2022 , the Company also had available federal research and development tax credit carryforwards of $ 38.9 million and $ 25.9 million, respectively, available to reduce future tax liabilities, which begin to expire beginning in 2035 . The Company also has state research and development tax credit carryforwards of $ 8.5 million and $ 5.6 million as of December 31, 2023 and 2022 , respectively, available to reduce future state tax liabilities, which expire at various dates beginning in 2030 . Utilization of NOL and research and development credit carryforwards may generally be subject to limitation under Sections 382 and 383 of the Internal Revenue Code of 1986 ("Sections 382 and 383") due to ownership changes that have occurred previously or could occur in the future. Such ownership changes may limit the amount of NOL and research and development credit carryforwards that can be utilized annually to offset any post-ownership change in taxable income and tax, respectively. The most recent Section 382 study was performed by the Company up to December 31, 2023, through which it was noted that a historic ownership change has likely occurred. Nonetheless, the Company has concluded that, as of December 31, 2023, the prospective utilization of NOL and research and development credit carryforwards from inception through December 31, 2023 (and, therefore, the corresponding Federal and state deferred tax assets) should not be restricted by Sections 382 and 383, although ownership changes after December 31, 2023 could impact the Company’s ability to utilize such tax attributes in the future. The Company recorded a valuation allowance against its deferred tax assets for the years ended December 31, 2023 and 2022 , because the Company’s management believes it is more likely than not that such assets will not be realized. The valuation allowance increased by approximately $ 69.3 million and $ 87.8 million for the years ended December 31, 2023 and 2022, respectively, primarily as a result of operating losses generated with no corresponding financial statement benefit. The Company had no unrecognized tax benefits as of December 31, 2023 and 2022. The Company files tax returns, as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by Federal and state jurisdictions, where applicable. There are currently no pending tax examinations. The Company’s tax years are still open under statute from inception to the present. In 2017, the Tax Cuts and Jobs Act of 2017 ("2017 Tax Act") was signed into law. Amongst other provisions, the 2017 Tax Act requires taxpayers to capitalize and amortize research and experimental (R&D) expenditures under Section 174 for tax years beginning after December 31, 2021. As such, the rule noted became effective for the Company during the year ended December 31, 2022, ultimately resulting in the capitalization of certain R&D costs within its tax provision. The Company will amortize such costs for tax purposes over 5 years if the R&D was performed in the United States and over 15 years if the R&D was performed outside the United States. In 2020, the Coronavirus Aid, Relief and Economic Security Act ("CARES Act") was signed into law. The CARES Act lifts certain deduction limitations originally imposed by the 2017 Tax Act. Corporate taxpayers may carryback NOLs originating during 2018 through 2020 for up to five years , which was not previously allowed under the 2017 Tax Act. The CARES Act also eliminates the 80 % of taxable income limitations by allowing corporate entities to fully utilize NOL carryforwards to offset taxable income in 2018, 2019, or 2020. Taxpayers may generally deduct interest up to the sum of 50 % of adjusted taxable income plus business interest income ( 30 % limit under the 2017 Tax Act) for tax years beginning January 1, 2019 and 2020. The CARES Act allows taxpayers with alternative minimum tax credits to claim a refund in 2020 for the entire amount of the credits instead of recovering the credits through refunds over a period of years, as originally enacted by the 2017 Tax Act. In addition, the CARES Act raises the corporate charitable deduction limit to 25 % of taxable income and makes qualified improvement property generally eligible for 15-year cost-recovery and 100 % bonus depreciation. The enactment of the CARES Act did not result in any adjustments to the Company’s income tax provision for the years ended December 31, 2023, 2022, and 2021, or to the Company’s net deferred tax assets as of December 31, 2023 and 2022 , since the Company has no t recorded any U.S. Federal or state income tax benefits for the net losses incurred in any year due to the uncertainty of realizing a benefit from such items.

Employee Benefits

Employee Benefits	12 Months Ended
Employee Benefits	Dec. 31, 2023
Postemployment Benefits [Abstract]
Retirement Benefits	15. Employee Benefits In 2016, the Company established a defined-contribution plan under Section 401(k) of the Internal Revenue Code (the "401(k) Plan"). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. The Company made matching contributions to the 401(k) Plan of $ 2.6 million, $ 2.3 million, and $ 1.2 million for the years ended December 31, 2023, 2022, and 2021 .

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events In preparing the consolidated financial statements as of December 31, 2023 , the Company evaluated subsequent events for recognition and measurement purposes through the filing date of this Annual Report on Form 10-K. The Company concluded that no events or transactions have occurred that require disclosure in the accompanying consolidated financial statements, except as otherwise described in the notes above.

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") for reporting on Form 10-K. The Company’s consolidated financial statements include the accounts of Relay Therapeutics, Inc. and its wholly-owned subsidiaries, Relay Securities Corporation and Relay ML Discovery, LLC. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the fair value of contingent milestone payments in connection with the acquisition of ZebiAI Therapeutics, Inc. ("ZebiAI"), the determination of the transaction price and standalone selling price of performance obligations under Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 606, Revenue from Contracts with Customers ("ASC 606"), the accrual of research and development and manufacturing expenses, the valuation of equity instruments, and the incremental borrowing rate for determining operating lease assets and liabilities. Estimates are periodically reviewed in light of changes in circumstances, facts, and experience.
Segment Information	Segment Information In general, 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 on how to allocate resources and assess performance. The Company's chief operating decision maker is the president and chief executive officer. The Company and the chief operating decision maker view the Company's operations as one operating segment. The Company's singular focus is on using innovative experimental and computational approaches on protein motion for making medicines to drug protein targets that have previously been intractable or inadequately addressed. The Company operates in the United States and all tangible assets are held in the United States.
Cash Equivalents	Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents. Cash equivalents, which consist of money market funds, are stated at fair value.
Restricted Cash	Restricted Cash As of December 31, 2023 and 2022, the Company had restricted cash of $ 2.7 million and $ 2.6 million, respectively, to secure letters of credit in connection with operating leases of the Company’s facilities, as detailed in Note 13, Leases . The Company classified the restricted cash as a noncurrent asset on its consolidated balance sheets, consistent with the terms of the lease agreements.
Investments	Investments Investments in marketable securities are classified as available-for-sale. Available-for-sale securities are measured and reported at fair value using quoted prices in active markets for similar securities. Premiums or discounts from par value are amortized to investment income over the life of the underlying investment. In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). Certain amendments thereto were also issued by the FASB. The Company adopted ASU 2016-13, as well as the related amendments thereto, on January 1, 2022, pursuant to which the Company reviews investments whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. In connection therewith, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors, considering the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security is compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded on the consolidated balance sheet, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that is not related to credit is recognized in other comprehensive loss as a separate component of stockholders' equity. Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense in general and administrative expenses within the consolidated statements of operations and comprehensive loss. Losses are charged against the allowance when the Company believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. All of the Company’s available-for-sale securities are available to the Company for use in current operations. As a result, the Company classified all such securities as current assets as of December 31, 2023 and 2022, although the stated maturity of some individual securities may be one year or more beyond the balance sheet dates. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in general and administrative expenses within the consolidated statements of operations and comprehensive loss.
Concentration of Credit Risk and Significant Suppliers	Concentration of Credit Risk and Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and investments. From time to time, the Company has maintained all of its cash, cash equivalents, and investments at certain accredited financial institutions in amounts that exceed federally insured limits. The Company generally invests its excess capital in money market funds, U.S. treasury bonds, U.S. treasury bills, and agency bonds, all of which are subject to minimal credit and market risk. Management has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The investment portfolio is maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards, and limits the credit exposure of any single issuer. The Company is dependent on third-party suppliers for research and development activities of its programs, including preclinical and clinical testing. In particular, the Company relies and expects to continue to rely on a small number of these suppliers, including D. E. Shaw Research, LLC, as discussed in Note 12, Commitments and Contingencies , to meet its requirements for certain of its programs. These programs could be adversely affected by a significant interruption in preclinical and clinical testing, as well as the supply of active pharmaceutical ingredients and formulated drugs.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies, and similar techniques.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the useful life of the asset. Laboratory and computer equipment are depreciated over three years . Furniture and fixtures are depreciated over five years . Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the underlying asset. Expenditures for repairs and maintenance of assets are charged to expense as incurred. Upon retirement or sale, the cost and related accumulated depreciation of assets disposed of are removed from the accounts and any resulting gain or loss is included in loss from operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company continually evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book values of the assets to the expected future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured in an amount by which the book values of the assets exceed their fair value. The Company did no t recognize any impairment losses for the years ended December 31, 2023, 2022, and 2021 .
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include salaries, stock compensation and benefits of employees, third-party license fees, and other operational costs related to the Company’s research and development activities, including allocated facility-related expenses and external costs of outside vendors engaged to conduct both preclinical studies and clinical trials. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made.
Patent Costs	Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.
Stock Compensation	Stock Compensation For stock options and restricted stock units ("RSUs") granted to employees, directors, and other consultants with vesting over specified periods of continued service, the Company measures their fair value on the grant date using (a) the Black-Scholes Option Pricing Model for stock options and (b) the Company’s closing stock price on such date for RSUs. In connection therewith, compensation expense for such awards is recognized under the straight-line method over the requisite service period, which is generally the vesting period. The Company recognizes the impact of forfeitures on compensation expense as they occur. For stock options and RSUs granted to employees, directors, and other consultants with vesting over specified periods of continued service and contingent upon achievement of certain performance conditions, the Company measures their fair value on the grant date using (a) the Black-Scholes Option Pricing Model for stock options and (b) the Company’s closing stock price on such date for RSUs. In connection therewith, compensation expense for such awards is recognized under the accelerated attribution method over the requisite service period, which is generally the vesting period. The Company recognizes the impact of forfeitures on compensation expense as they occur. During the year ended December 31, 2023 , the Company granted stock options and RSUs to certain employees, with vesting over specified periods of continued service and contingent upon achievement of certain market conditions. The Company measured the fair value of such awards on the grant date using a Monte Carlo Simulation, incorporating various option pricing inputs. In connection therewith, compensation expense for such awards is recognized under the accelerated attribution method over the requisite service period, regardless of whether the market conditions have been achieved. The Company recognizes the impact of forfeitures from market-based awards on compensation expense as they occur.
Revenue Recognition	Revenue Recognition The Company accounts for revenue recognition in accordance with ASC 606, pursuant to which an entity recognizes revenue when its customer obtains control of promised goods or services in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with customer(s); (ii) identify the performance obligation(s) in the contract(s); (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract(s); and (v) recognize revenue when (or as) the entity satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within the contract and determines those that are performance obligations. The Company then determines the transaction price and allocates it to the performance obligations. As part of the accounting for such arrangements, the Company must use judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above, including the determination of whether milestones or other variable consideration should be included in the transaction price; and (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of the transaction price in step (iv) above. The Company utilizes key assumptions and judgments in (a) determining the stand-alone selling price for each performance obligation, which may include discounted cash flow models, evaluation of comparable transactions, and pricing considered in negotiating the transaction and estimated costs, and (b) determining how the transaction price is allocated amongst the performance obligations. The Company also uses judgment to determine whether milestones or other variable consideration should be included in the transaction price. As part of management’s evaluation of the transaction price, the Company considers numerous factors, including whether the achievement of the milestones is outside of the Company's control, contingent upon the efforts of others, or subject to scientific risks of success. If the Company concludes it is probable that a significant revenue reversal would not occur, the associated milestone payment is included in the transaction price. Milestone payments that are not within the Company's control, such as regulatory approvals, are generally not considered probable until those milestones are achieved. The Company re-evaluates the transaction price, including estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as uncertain events are resolved or other changes in circumstances occur. For revenue-based royalties, including milestone payments based on the level of sales, the Company will include royalties in the transaction price at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty is allocated has been satisfied (or partially satisfied). Once the performance obligations are identified, the transaction price is allocated to each performance obligation based on the relative stand-alone selling price. The Company then recognizes as revenue the amount of the transaction price allocated to the respective performance obligation when (or as) it is satisfied, either at a point in time or over time. If the performance obligation is satisfied over time, the Company recognizes revenue based on the use of either an output or input method.
Collaboration Agreements	Collaboration Agreements The Company enters into collaborative agreements with third parties to research, develop, and commercialize drug candidates, pursuant to which the risks and rewards for such activities are shared between the parties. Such arrangements also provide for cost sharing between the parties during the research and development phase, as well as potential future profit share payments during the commercialization phase. In general, such contracts are evaluated under the provisions of FASB ASC 808, Collaborative Arrangements ("ASC 808"). The amounts receivable and payable for research and development activities are presented net within research and development expense on the consolidated statements of operations and comprehensive loss. As such, the net costs reflect the Company’s share of the ongoing research and development efforts. The amounts receivable and payable for commercialization activities are presented net as either collaboration revenue, separate from revenue from contracts with customers, or collaboration expense on the consolidated statements of operations, as appropriate.
Research and Manufacturing Contracts	Research and Manufacturing Contracts The Company has entered into various research and development contracts with research institutions and other companies whose costs are included in research and development expense in the accompanying consolidated statements of operations and comprehensive loss. These agreements are generally cancelable and related payments are recorded as research and development expenses as the underlying services are performed. When evaluating the adequacy of the expense recognized, the Company analyzes progress of the services, including the phase or completion of events, invoices received, and contracted costs. Judgments and estimates are made in determining the expense recognized and the related prepaid or accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical estimates have not been materially different from the actual costs.
Lease Agreements	Lease Agreements Pursuant to ASC 842, Leases , the Company determines if an arrangement is or contains a lease at inception. For leases with a term of 12 months or less, the Company does not recognize a right-of-use asset or lease liability. The Company’s operating leases are recognized on its consolidated balance sheets as other noncurrent assets, other current liabilities, and other noncurrent liabilities. The Company does not have any finance leases. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As the Company’s leases typically do not provide an implicit rate, the Company uses an estimate of its incremental borrowing rate based on the information available at the lease commencement date in determining the present value of lease payments. Operating lease right-of-use assets also include the effect of any lease payments made prior to commencement and exclude lease incentives. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. The Company has lease agreements with lease and non-lease components, which are accounted for as a combined element.
Acquired In-Process Research and Development	Acquired In-Process Research and Development In an asset acquisition, the cost allocated to acquire in-process research and development ("IPR&D") with no alternative future use is charged to expense at the acquisition date. Please refer to Note 10, Acquisition of ZebiAI , for a more detailed description of the accounting policies applied to the Company's only asset acquisition during the three years ended December 31, 2023 .
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2023, 2022, and 2021 , other comprehensive income (loss) consisted of changes in unrealized gains and losses from available-for-sale investments.
Net Loss Per Common Share	Net Loss per Common Share Basic net loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed using the sum of the weighted-average number of common shares outstanding during the period and the effect of any dilutive securities. For periods in which the Company reports a net loss, diluted net loss per share is the same as basic net loss per share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. For additional discussion of net loss per common share, please refer to Note 9, Net Loss per Share.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts and the tax bases of the assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements As noted above, the Company adopted ASU 2016-13, as well as the related amendments thereto, on January 1, 2022. The adoption of ASU 2016-13, as well as the related amendments thereto, did not have a material impact on the Company’s consolidated financial statements or disclosures.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which is intended to provide enhancements to segment disclosures, even for entities with only one reportable segment. In particular, the standard will require disclosures of significant segment expenses regularly provided to the chief operating decision maker and included within each reported measure of segment profit and loss. The standard will also require disclosure of all other segment items by reportable segment and a description of its composition. Finally, the standard will require disclosure of the title and position of the chief operating decision maker and an explanation of how the chief operating decision maker uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. The standard is effective for annual periods beginning after December 15, 2023, and interim periods within annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of the standard on the presentation of its consolidated financial statements and footnotes. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which is intended to provide enhancements to annual income tax disclosures. In particular, the standard will require more detailed information in the income tax rate reconciliation, as well as the disclosure of income taxes paid disaggregated by jurisdiction, among other enhancements. The standard is effective for years beginning after December 15, 2024 and early adoption is permitted. The Company is currently evaluating the impact of the standard on the presentation of its consolidated financial statements and footnotes.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis and Level of the Fair Value Hierarchy	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total (in thousands) Assets Cash equivalents: Money market funds $ 140,466 $ — $ — $ 140,466 Total cash equivalents 140,466 — — 140,466 Investments: U.S. treasury bills — 416,008 — 416,008 U.S. agency securities — 190,342 — 190,342 Total investments — 606,350 — 606,350 Total assets $ 140,466 $ 606,350 $ — $ 746,816 Liabilities Contingent Milestone Payments $ — $ — $ 8,206 $ 8,206 Total liabilities $ — $ — $ 8,206 $ 8,206 Fair Value Measurements as of Level 1 Level 2 Level 3 Total (in thousands) Assets Cash equivalents: Money market funds $ 118,446 $ — $ — $ 118,446 U.S. treasury bills — 9,950 — 9,950 Total cash equivalents 118,446 9,950 — 128,396 Investments: U.S. treasury bills — 466,603 — 466,603 U.S. agency securities — 380,520 — 380,520 Total investments — 847,123 — 847,123 Total assets $ 118,446 $ 857,073 $ — $ 975,519 Liabilities Contingent Milestone Payments $ — $ — $ 27,378 $ 27,378 Total liabilities $ — $ — $ 27,378 $ 27,378
Schedule of Changes in Contingent Consideration Liability	The following table reconciles the change in the contingent consideration liability: Year Ended December 31, 2023 2022 2021 (in thousands) Balance at beginning of period $ 32,378 $ 50,258 $ — Fair value of contingent consideration upon acquisition — — 47,422 Change in fair value of Contingent Milestone Payments ( 6,422 ) ( 11,677 ) 2,836 Common stock issued upon milestone achievement ( 12,750 ) ( 6,203 ) — $ 13,206 $ 32,378 $ 50,258

Investments (Tables)

Investments (Tables)	12 Months Ended
Investments (Tables)	Dec. 31, 2023
Schedule of Investments [Abstract]
Summary of Fair Value of Available-for-Sale Investments by Type of Security	The following tables present the fair value of available-for-sale investments by type of security: December 31, 2023 Amortized Unrealized Unrealized Fair (in thousands) Investments: U.S. treasury bills $ 314,957 $ 83 $ ( 482 ) $ 314,558 U.S. agency securities 185,672 24 ( 353 ) 185,343 Total investments with a maturity of one year or less 500,629 107 ( 835 ) 499,901 U.S. treasury bills 100,917 591 ( 58 ) 101,450 U.S. agency securities 5,000 — ( 1 ) 4,999 Total investments with a maturity of one to two years 105,917 591 ( 59 ) 106,449 Total investments $ 606,546 $ 698 $ ( 894 ) $ 606,350 December 31, 2022 Amortized Unrealized Unrealized Fair (in thousands) Investments: U.S. treasury bills $ 356,728 $ 9 $ ( 5,523 ) $ 351,214 U.S. agency securities 236,483 49 ( 3,104 ) 233,428 Total investments with a maturity of one year or less 593,211 58 ( 8,627 ) 584,642 U.S. treasury bills 116,290 14 ( 915 ) 115,389 U.S. agency securities 148,042 36 ( 986 ) 147,092 Total investments with a maturity of one to two years 264,332 50 ( 1,901 ) 262,481 Total investments $ 857,543 $ 108 $ ( 10,528 ) $ 847,123
Available-for-sale Debt Securities in an Unrealized Loss Position	The following tables summarize the Company's available-for-sale debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by major security type and length of time in a continuous unrealized loss position: December 31, 2023 Less than 12 Months 12 Months or Longer Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (in thousands) U.S. treasury bills $ 172,625 $ ( 371 ) $ 27,822 $ ( 169 ) $ 200,447 $ ( 540 ) U.S. agency securities 136,356 ( 207 ) 36,742 ( 147 ) 173,098 ( 354 ) Total $ 308,981 $ ( 578 ) $ 64,564 $ ( 316 ) $ 373,545 $ ( 894 ) December 31, 2022 Less than 12 Months 12 Months or Longer Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (in thousands) U.S. treasury bills $ 143,089 $ ( 1,860 ) $ 275,445 $ ( 4,578 ) $ 418,534 $ ( 6,438 ) U.S. agency securities 190,468 ( 1,649 ) 97,305 ( 2,441 ) 287,773 ( 4,090 ) Total $ 333,557 $ ( 3,509 ) $ 372,750 $ ( 7,019 ) $ 706,307 $ ( 10,528 )

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
Property and Equipment (Tables)	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following: December 31, 2023 2022 (in thousands) Property and equipment: Laboratory equipment $ 25,558 $ 21,472 Leasehold improvements 3,826 3,826 Computer equipment 1,743 1,743 Furniture and fixtures 1,779 1,762 Construction in process 1,577 1,220 34,483 30,023 Less: accumulated depreciation ( 23,582 ) ( 18,389 ) Total property and equipment, net $ 10,901 $ 11,634

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
Accrued Expenses (Tables)	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following: December 31, 2023 2022 (in thousands) External research and development costs $ 12,509 $ 19,276 Consulting and professional services 886 831 Compensation costs 702 1,043 Other 793 1,553 Total accrued expenses $ 14,890 $ 22,703

Stock Compensation (Tables)

Stock Compensation (Tables)	12 Months Ended
Stock Compensation (Tables)	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Schedule of Total Stock Compensation Expense Recognized	In connection with all stock-based payments, total stock compensation expense recognized was as follows: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 48,351 $ 30,671 $ 24,922 General and administrative expenses 37,680 25,467 23,532 $ 86,031 $ 56,138 $ 48,454
Schedule of Restricted Stock Units Activity	The following table summarizes activity for RSUs under the 2020 Stock Plan for the year ended December 31, 2023: Number of Shares Underlying RSUs Weighted-Average Unvested at December 31, 2022 1,566,760 $ 24.62 Granted 2,591,453 17.74 Vested ( 883,652 ) 21.50 Cancelled ( 282,314 ) 24.00 Unvested at December 31, 2023 2,992,247 19.14
Schedule of Estimated Fair Value of Employee Stock Purchase Plan	The following table summarizes activity under the Company's ESPP from the initial offering period, or July 1, 2021 through December 31, 2023, including (a) after-tax contributions from employees, (b) shares purchased, and (c) weighted-average assumptions used in the Black-Scholes option pricing model to estimate the fair value of the option component of the shares purchased under the ESPP in each period. Year Ended December 31, 2023 2022 2021 After-tax contributions (in thousands) $ 2,486 $ 1,686 $ 1,141 Shares of common stock purchased 244,125 123,019 43,685 Expected term (in years) 0.50 0.50 0.50 Risk-free interest rate 5.0 % 1.0 % 0.1 % Expected volatility 86.8 % 74.4 % 65.1 % Expected dividend yield 0.0 % 0.0 % 0.0 %
Time-Based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Schedule of Stock Option Activity	The following table summarizes activity for time-based stock options under the 2016 Stock Plan and the 2020 Stock Plan for the year ended December 31, 2023: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2022 9,276,552 $ 18.33 7.85 $ 34,647 Granted 4,129,710 18.64 Exercised ( 366,025 ) 4.95 Cancelled ( 648,422 ) 23.52 Outstanding at December 31, 2023 12,391,815 $ 18.56 7.58 $ 18,907 Vested at December 31, 2023 6,651,356 $ 16.57 6.68 $ 18,559 Unvested at December 31, 2023 5,740,459 $ 20.87 8.62 $ 348
Schedule of Estimated Fair Value of Stock Options	The following table summarizes the assumptions used in calculating the fair value of the time-based stock options granted. Year Ended December 31, 2023 2022 2021 Expected term (in years) 6.25 6.25 6.25 Risk-free interest rate 3.3 % to 5.0 % 1.6 % to 4.2 % 0.6 % to 1.6 % Expected volatility 74.1 % to 79.8 % 72.7 % to 76.2 % 74.7 % to 76.6 % Expected dividend yield 0.0 % 0.0 % 0.0 %
Performance-Based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Schedule of Stock Option Activity	The following table summarizes activity for performance-based stock options for the year ended December 31, 2023: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2022 1,774,183 $ 5.41 7.18 $ 17,128 Exercised ( 33,473 ) 5.22 Cancelled ( 34,759 ) 5.22 Outstanding at December 31, 2023 1,705,951 $ 5.42 6.18 $ 9,808 Vested at December 31, 2023 1,330,460 $ 5.27 6.17 $ 7,691 Unvested at December 31, 2023 375,491 $ 5.96 6.21 $ 2,117

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
Net Loss Per Share (Tables)	Dec. 31, 2023
Earnings Per Share [Abstract]
Summary of Computation of Basic and Diluted Net Loss Per Share	The following table summarizes the computation of basic and diluted net loss per share of the Company: Year Ended December 31, 2023 2022 2021 (in thousands, except share and per share data) Net loss $ ( 341,973 ) $ ( 290,509 ) $ ( 363,872 ) Net loss per share, basic and diluted $ ( 2.79 ) $ ( 2.59 ) $ ( 3.82 ) Weighted average shares of common stock, basic and diluted 122,576,527 112,233,649 95,136,719
Summary of Antidilutive Securities Excluded From Computation of Earnings Per Share	For the years ended December 31, 2023, 2022, and 2021, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same. In computing diluted net loss per share for the years ended December 31, 2023, 2022, and 2021, the Company excluded the following potentially dilutive securities, as the effect would be anti-dilutive and reduce the net loss per share calculated for each period. Year Ended December 31, 2023 2022 2021 Options outstanding to purchase common stock 15,610,586 11,050,735 8,719,627 Unvested and outstanding restricted stock units 3,398,017 1,566,760 691,205 Common stock issued upon milestone achievement 1,535,404 201,569 — 20,544,007 12,819,064 9,410,832

Acquisition of ZebiAI (Tables)

Acquisition of ZebiAI (Tables)	12 Months Ended
Acquisition of ZebiAI (Tables)	Dec. 31, 2023
Business Combination, Description [Abstract]
Summary of Net Assets Acquired Based on Estimated Fair Values	The following table summarizes net assets acquired based on their estimated fair values as of the Acquisition Date: Amount (in thousands) Acquired IPR&D asset $ 123,000 Loss on initial consolidation of VIE 11,855 Assets obtained in asset acquisition 662 Liabilities assumed in asset acquisition ( 2,330 ) Intangible asset 2,300 Net acquired assets $ 135,487

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Summary of Reconciliation of Expected Income Tax (Benefit) Computed Using Federal Statutory Income Tax Rate to Effective Income Tax Rate	A reconciliation of the expected income tax (benefit) computed using the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023, 2022, and 2021: December 31, 2023 2022 2021 Income tax computed at federal statutory rate 21.0 % 21.0 % 21.0 % State taxes, net of federal benefit ( 3.7 )% 6.5 % 5.7 % Change in valuation allowance ( 20.3 )% ( 30.2 )% ( 20.5 )% IPR&D 0.0 % 0.0 % ( 7.0 )% R&D credit carryovers 4.5 % 4.2 % 2.2 % Stock compensation ( 1.7 )% ( 2.1 )% ( 0.4 )% Permanent differences 0.2 % ( 0.6 )% ( 1.0 )% Total 0.0 % 0.0 % 0.0 %
Summary of Deferred Tax Assets and Liabilities	The Company’s deferred tax assets and liabilities at December 31, 2023 and 2022, consist of the following: December 31, 2023 2022 (in thousands) Deferred tax assets: Net operating losses $ 141,453 $ 119,688 Tax credit carryforwards 45,969 30,593 Capitalized R&D 90,273 55,303 Lease liability 12,914 18,307 Stock compensation 19,448 14,510 Intangibles 1,261 1,875 Depreciation and amortization 505 568 Other 263 7,270 Total gross deferred tax assets 312,086 248,114 Valuation allowance ( 299,829 ) ( 230,518 ) Net deferred tax assets 12,257 17,596 Deferred tax liabilities Operating lease assets ( 12,257 ) ( 17,596 ) Total deferred tax liabilities ( 12,257 ) ( 17,596 ) $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2023
399 Binney Street [Member]
Operating Leased Assets [Line Items]
Schedule of Operating Leases Presentation in Consolidated Balance Sheets	The following table summarizes the presentation of amounts recorded on the Company’s consolidated balance sheets for the operating lease at 399 Binney Street as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 (in thousands) Assets: Operating lease assets $ 16,670 $ 18,828 Liabilities: Operating lease liabilities $ 2,535 $ 2,170 Operating lease liabilities, net of current portion 16,352 18,886 Total operating lease liabilities $ 18,887 $ 21,056
Summary of Operating Lease Presentation in Consolidated Statements of Operations and Comprehensive Loss	The following table summarizes the effect of lease costs for the Company's operating lease at 399 Binney Street on the Company’s condensed consolidated statements of operations and comprehensive loss for the years ended December 31, 2023, 2022, and 2021: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 3,631 $ 3,350 $ 3,262 General and administrative expenses 614 893 1,002 $ 4,245 $ 4,243 $ 4,264
Summary of Future Minimum Lease Payments	he minimum lease payments for the Company’s operating lease at 399 Binney Street for the next five years and thereafter are expected to be as follows: Year Ending December 31, Amount (in thousands) 2024 4,377 2025 4,503 2026 4,634 2027 4,768 2028 4,906 Thereafter 1,651 Total lease payments 24,839 Less: interest ( 5,952 ) Present value of operating lease liabilities $ 18,887
60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Schedule of Operating Leases Presentation in Consolidated Balance Sheets	The following table summarizes the presentation of amounts recorded on the Company’s consolidated balance sheets for the operating lease at 60 Hampshire Street as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 (in thousands) Assets: Operating lease assets $ 41,299 $ 44,926 Liabilities: Current operating lease liabilities $ 2,429 $ 2,106 Operating lease liabilities, net of current portion 32,150 34,580 Total operating lease liabilities $ 34,579 $ 36,686
Summary of Operating Lease Presentation in Consolidated Statements of Operations and Comprehensive Loss	The following table summarizes the effect of lease costs for the Company's operating lease at 60 Hampshire Street on the Company’s condensed consolidated statements of operations and comprehensive loss for the years ended December 31, 2023, 2022, and 2021: Year Ended December 31, 2023 2022 2021 (in thousands) Research and development expenses $ 5,549 $ 2,675 $ — General and administrative expenses 938 564 — $ 6,487 $ 3,239 $ —
Summary of Future Minimum Lease Payments	he minimum lease payments for the Company’s operating lease at 60 Hampshire Street for the next five years and thereafter are expected to be as follows: Year Ending December 31, Amount (in thousands) 2024 5,109 2025 5,257 2026 5,409 2027 5,565 2028 5,726 Thereafter 21,358 Total lease payments 48,424 Less: interest ( 13,845 ) Present value of operating lease liabilities $ 34,579

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Detail) $ in Thousands	Dec. 31, 2023 USD ($) Program	Dec. 31, 2022 USD ($)
Nature of Business and Basis of Presentation [Line Items]
Accumulated deficit \| $	$ (1,400,582)	$ (1,058,609)
Precision Oncology And Genetic Diseases [Member] \| Minimum [Member]
Nature of Business and Basis of Presentation [Line Items]
Number of discovery stage programs \| Program	7

Significant Accounting Polici_2

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segments \| Segment	1
Maturity days for highly liquid investments	The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents.
Restricted cash	$ 2,707,000	$ 2,578,000
Operating lease option to extent	true
Operating lease option to terminate	true
Impairment loss of long lived assets	$ 0	0	$ 0
Description of Income tax benefit, likelihood of realized upon ultimate settlement	greater than 50%
Laboratory and Computer Equipment [Member]
Significant Accounting Policies [Line Items]
Property and equipment, useful life	3 years
Furniture and Fixtures [Member]
Significant Accounting Policies [Line Items]
Property and equipment, useful life	5 years
Letter of Credit [Member]
Significant Accounting Policies [Line Items]
Restricted cash	$ 2,700,000	$ 2,600,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis and Level of the Fair Value Hierarchy (Detail) - Fair value on a recurring basis [Member] - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Investments:
Total assets	$ 746,816	$ 975,519
Liabilities
Contingent Milestone Payments	8,206	27,378
Total liabilities	8,206	27,378
Level 1 [Member]
Investments:
Total assets	140,466	118,446
Level 2 [Member]
Investments:
Total assets	606,350	857,073
Level 3 [Member]
Liabilities
Contingent Milestone Payments	8,206	27,378
Total liabilities	8,206	27,378
Investments [Member]
Investments:
Total investments	606,350	847,123
Investments [Member] \| U.S. treasury bills [Member]
Investments:
Total investments	416,008	466,603
Investments [Member] \| U.S. agency securities [Member]
Investments:
Total investments	190,342	380,520
Investments [Member] \| Level 2 [Member]
Investments:
Total investments	606,350	847,123
Investments [Member] \| Level 2 [Member] \| U.S. treasury bills [Member]
Investments:
Total investments	416,008	466,603
Investments [Member] \| Level 2 [Member] \| U.S. agency securities [Member]
Investments:
Total investments	190,342	380,520
Cash equivalents [Member]
Cash equivalents:
Assets, fair value	140,466	128,396
Cash equivalents [Member] \| Money market funds [Member]
Cash equivalents:
Assets, fair value	140,466	118,446
Cash equivalents [Member] \| U.S. treasury bills [Member]
Cash equivalents:
Assets, fair value		9,950
Cash equivalents [Member] \| Level 1 [Member]
Cash equivalents:
Assets, fair value	140,466	118,446
Cash equivalents [Member] \| Level 1 [Member] \| Money market funds [Member]
Cash equivalents:
Assets, fair value	$ 140,466	118,446
Cash equivalents [Member] \| Level 2 [Member]
Cash equivalents:
Assets, fair value		9,950
Cash equivalents [Member] \| Level 2 [Member] \| U.S. treasury bills [Member]
Cash equivalents:
Assets, fair value		$ 9,950

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - ZebiAI [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Apr. 22, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business combination contingent consideration liability, contingent earnout payments		$ 100
Contingent consideration payment description	The outstanding Contingent Milestone Payments are payable in shares of the Company's common stock based on a fixed amount assigned to each milestone and the volume weighted-average closing price of the Company’s common stock for a specified period prior to the milestone achievement.
Number of shares that would be issued upon milestone achievement	5,272,112
Average stock price upon milestone settlement	$ 11.29
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business combination contingent consideration liability contingent milestones payments		85
Business combination contingent consideration liability, contingent earnout payments		$ 100

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Changes in Fair Value of Contingent Consideration Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ 32,378	$ 50,258
Fair value of Contingent Milestone Payments upon acquisition			$ 47,422
Change in fair value of Contingent Milestone Payments	(6,422)	(11,677)	2,836
Common stock issued upon milestone achievement	(12,750)	(6,203)
Ending balance	$ 13,206	$ 32,378	$ 50,258

Investments - Summary of Fair V

Investments - Summary of Fair Value of Available-for-Sale Investments by Type of Security (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	$ 606,546	$ 857,543
Unrealized Gains	698	108
Unrealized Losses	(894)	(10,528)
Fair Value	606,350	847,123
Investments with a maturity of one year or less [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	500,629	593,211
Unrealized Gains	107	58
Unrealized Losses	(835)	(8,627)
Fair Value	499,901	584,642
Investments with a maturity of one to two years [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	105,917	264,332
Unrealized Gains	591	50
Unrealized Losses	(59)	(1,901)
Fair Value	106,449	262,481
U.S treasury bills [Member] \| Investments with a maturity of one year or less [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	314,957	356,728
Unrealized Gains	83	9
Unrealized Losses	(482)	(5,523)
Fair Value	314,558	351,214
U.S treasury bills [Member] \| Investments with a maturity of one to two years [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	100,917	116,290
Unrealized Gains	591	14
Unrealized Losses	(58)	(915)
Fair Value	101,450	115,389
U.S agency securities [Member] \| Investments with a maturity of one year or less [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	185,672	236,483
Unrealized Gains	24	49
Unrealized Losses	(353)	(3,104)
Fair Value	185,343	233,428
U.S agency securities [Member] \| Investments with a maturity of one to two years [Member]
Schedule Of Held To Maturity Securities [Line Items]
Amortized Cost	5,000	148,042
Unrealized Gains		36
Unrealized Losses	(1)	(986)
Fair Value	$ 4,999	$ 147,092

Investments - Additional Inform

Investments - Additional Information (Detail) - DebtSecurity	Dec. 31, 2023	Dec. 31, 2022
Investments [Abstract]
Debt securities unrealized loss position	70	126

Investments - Available-for-sal

Investments - Available-for-sale Debt Securities in an Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	$ 308,981	$ 333,557
Less than 12 Months, Unrealized Losses	(578)	(3,509)
12 Months or Longer, Fair Value	64,564	372,750
12 Months or Longer, Unrealized Losses	(316)	(7,019)
Total, Fair Value	373,545	706,307
Total, Unrealized Losses	(894)	(10,528)
U.S treasury bills [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	172,625	143,089
Less than 12 Months, Unrealized Losses	(371)	(1,860)
12 Months or Longer, Fair Value	27,822	275,445
12 Months or Longer, Unrealized Losses	(169)	(4,578)
Total, Fair Value	200,447	418,534
Total, Unrealized Losses	(540)	(6,438)
U.S agency securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Less than 12 Months, Fair Value	136,356	190,468
Less than 12 Months, Unrealized Losses	(207)	(1,649)
12 Months or Longer, Fair Value	36,742	97,305
12 Months or Longer, Unrealized Losses	(147)	(2,441)
Total, Fair Value	173,098	287,773
Total, Unrealized Losses	$ (354)	$ (4,090)

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant and Equipment [Line Items]
Property and equipment	$ 34,483	$ 30,023
Less: accumulated depreciation	(23,582)	(18,389)
Total property and equipment, net	10,901	11,634
Laboratory Equipment [Member]
Property Plant and Equipment [Line Items]
Property and equipment	25,558	21,472
Leasehold Improvements [Member]
Property Plant and Equipment [Line Items]
Property and equipment	3,826	3,826
Computer Equipment [Member]
Property Plant and Equipment [Line Items]
Property and equipment	1,743	1,743
Furniture and Fixtures [Member]
Property Plant and Equipment [Line Items]
Property and equipment	1,779	1,762
Construction in Process [Member]
Property Plant and Equipment [Line Items]
Property and equipment	$ 1,577	$ 1,220

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 5,269	$ 4,130	$ 3,925

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
External research and development costs	$ 12,509	$ 19,276
Consulting and professional services	886	831
Compensation costs	702	1,043
Other	793	1,553
Total accrued expenses	$ 14,890	$ 22,703

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($)	1 Months Ended				12 Months Ended			17 Months Ended
Common Stock - Additional Information (Detail) - USD ($)	Jan. 31, 2024	Sep. 30, 2022	Oct. 31, 2021	Aug. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Voting Rights					Each share of common stock entitles the stockholder to one vote on all matters submitted to a vote of the Company’s stockholders.
Dividends declared					$ 0
Common stock restriction period					4 years
Private Placement [Member] \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares sold	2,500,000
Offering price per share	$ 12
Net proceeds	$ 30,000,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares sold		11,320,755	15,188,679		3,026,072	11,320,755	15,188,679
Additional shares issued			1,981,132
Offering price per share		$ 26.5	$ 26.5
Net proceeds		$ 284,700,000	$ 382,200,000
Underwriting discounts, commissions and other offering expenses		$ 15,300,000	$ 20,300,000
Common Stock [Member] \| Sales Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares sold					3,026,072			0
Offering price per share					$ 10.26
Net proceeds					$ 30,300,000
Commissions and other offering expenses					$ 800,000
Common Stock [Member] \| Cowen [Member] \| Sales Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate gross proceeds from the sale of shares				$ 300,000,000

Stock Compensation - Additional

Stock Compensation - Additional Information (Detail) - USD ($)			12 Months Ended
	Jan. 01, 2023	Jan. 01, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Aug. 01, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense			$ 86,031,000	$ 56,138,000	$ 48,454,000
Time-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value			$ 4,400,000	$ 15,500,000	$ 32,400,000
Weighted average grant date fair value of stock option granted			$ 12.83	$ 13.67	$ 22.95
Total unrecognized compensation cost related to the unvested stock awards, Value			$ 73,100,000
Total unrecognized compensation cost related to the unvested stock awards, Weighted average period			1 year 4 months 6 days
Number of stock options granted			4,129,710
Expected term from grant through exercise			6 years 3 months	6 years 3 months	6 years 3 months
Dividend yield rate			0%	0%	0%
Number of shares exercised			366,025
Number of shares, cancelled			648,422
Performance-Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value			$ 300,000	$ 400,000	$ 1,100,000
Weighted average grant date fair value of stock option granted					$ 20.28
Total unrecognized compensation cost related to the unvested stock awards, Value			$ 1,900,000
Total unrecognized compensation cost related to the unvested stock awards, Weighted average period			5 months 23 days
Number of stock options granted			0	0
Number of shares exercised			33,473
Number of shares, cancelled			34,759
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares, vested			$ 10,500,000
Total unrecognized compensation cost related to the unvested stock awards, Value			$ 51,300,000
Total unrecognized compensation cost related to the unvested stock awards, Weighted average period			1 year 4 months 28 days
Number of RSUs, cancelled			282,314
Number of RSUs, vested			883,652
2016 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized							0
2020 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized			9,160,736			8,376,080
Percentage of additional common stock authorized		5%
Increase in number of shares of common stock available for issuance	6,056,111
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized			3,874,096			1,092,532
Percentage of additional common stock authorized						1%
Increase in number of shares of common stock available for issuance	1,211,222
Percentage of fair market value of common stock						85%
Shares authorized additionally under ESPP		2,185,064
Total unrecognized compensation cost related to the unvested stock awards, Value			$ 0
Expected term from grant through exercise			6 months	6 months	6 months
Risk-free interest rate			5%	1%	0.10%
Historical volatility rate			86.80%	74.40%	65.10%
Dividend yield rate			0%	0%	0%
Market-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense			$ 25,500,000
Total unrecognized compensation cost related to the unvested stock awards, Value			$ 9,000,000
Total unrecognized compensation cost related to the unvested stock awards, Weighted average period			2 years 25 days
Market-Based Awards [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU granted			405,770
Vesting period			3 years
Expected term from grant through exercise			6 years 6 months
Risk-free interest rate			3.50%
Historical volatility rate			75%
Dividend yield rate			0%
Fair value of market based awards			$ 16.11
Contractual term of stock options			10 years
Grant date share price			$ 20.45
Number of RSUs, cancelled			0
Number of shares, released			0
Number of RSUs, vested			0
Market-Based Awards [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted			1,512,820
Vesting period			3 years
Expected term from grant through exercise			6 years 6 months
Risk-free interest rate			3.50%
Historical volatility rate			75%
Dividend yield rate			0%
Fair value of market based awards			$ 12.53
Contractual term of stock options			10 years
Exercise price of stock options			$ 20.45
Number of shares exercised			0
Number of shares, cancelled			0
Number of shares, vested			0

Stock Compensation - Schedule o

Stock Compensation - Schedule of Total Stock Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 86,031	$ 56,138	$ 48,454
Research and development expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	48,351	30,671	24,922
General and administrative expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 37,680	$ 25,467	$ 23,532

Stock Compensation - Schedule_2

Stock Compensation - Schedule of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Time-Based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options and Warrants Outstanding, Number of Shares Beginning Balance	9,276,552
Granted, Number of Shares	4,129,710
Exercised, Number of Shares	(366,025)
Cancelled, Number of Shares	(648,422)
Options and Warrants Outstanding, Number of Shares Ending Balance	12,391,815	9,276,552
Shares, Vested	6,651,356
Shares, Unvested	5,740,459
Weighted Average Exercise Price Per Share, Outstanding Beginning Balance	$ 18.33
Weighted Average Exercise Price Per Share, Granted	18.64
Weighted Average Exercise Price Per Share, Exercised	4.95
Weighted Average Exercise Price Per Share, Cancelled	23.52
Weighted Average Exercise Price Per Share, Outstanding Ending Balance	18.56	$ 18.33
Weighted Average Exercise Price Per Share, Vested	16.57
Weighted Average Exercise Price Per Share, Unvested	$ 20.87
Weighted Average Remaining Contractual Life, Outstanding	7 years 6 months 29 days	7 years 10 months 6 days
Weighted Average Remaining Contractual Life, Vested	6 years 8 months 4 days
Weighted Average Remaining Contractual Life, Unvested	8 years 7 months 13 days
Aggregate Intrinsic Value, Outstanding Value	$ 18,907	$ 34,647
Aggregate Intrinsic Value, Vested Value	18,559
Aggregate Intrinsic Value, Unvested Value	$ 348
Performance-Based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options and Warrants Outstanding, Number of Shares Beginning Balance	1,774,183
Granted, Number of Shares	0	0
Exercised, Number of Shares	(33,473)
Cancelled, Number of Shares	(34,759)
Options and Warrants Outstanding, Number of Shares Ending Balance	1,705,951	1,774,183
Shares, Vested	1,330,460
Shares, Unvested	375,491
Weighted Average Exercise Price Per Share, Outstanding Beginning Balance	$ 5.41
Weighted Average Exercise Price Per Share, Exercised	5.22
Weighted Average Exercise Price Per Share, Cancelled	5.22
Weighted Average Exercise Price Per Share, Outstanding Ending Balance	5.42	$ 5.41
Weighted Average Exercise Price Per Share, Vested	5.27
Weighted Average Exercise Price Per Share, Unvested	$ 5.96
Weighted Average Remaining Contractual Life, Outstanding	6 years 2 months 4 days	7 years 2 months 4 days
Weighted Average Remaining Contractual Life, Vested	6 years 2 months 1 day
Weighted Average Remaining Contractual Life, Unvested	6 years 2 months 15 days
Aggregate Intrinsic Value, Outstanding Value	$ 9,808	$ 17,128
Aggregate Intrinsic Value, Vested Value	7,691
Aggregate Intrinsic Value, Unvested Value	$ 2,117

Stock Compensation - Schedule_3

Stock Compensation - Schedule of Estimated Fair Value of Stock Options (Detail) - Time-Based Stock Options [Member]	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	6 years 3 months	6 years 3 months	6 years 3 months
Risk-free interest rate minimum	3.30%	1.60%	0.60%
Risk-free interest rate maximum	5%	4.20%	1.60%
Expected volatility rate minimum	74.10%	72.70%	74.70%
Expected volatility rate maximum	79.80%	76.20%	76.60%
Expected dividend yield	0%	0%	0%

Stock Compensation - Schedule_4

Stock Compensation - Schedule of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares - Beginning \| shares	1,566,760
Number of Shares Underlying RSUs, Granted \| shares	2,591,453
Number of Shares Underlying RSUs, Vested \| shares	(883,652)
Number of Shares Underlying RSUs, Cancelled \| shares	(282,314)
Shares - Ending \| shares	2,992,247
Weighted Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 24.62
Weighted Average Grant Date Fair Value, Granted \| $ / shares	17.74
Weighted Average Grant Date Fair Value, Vested \| $ / shares	21.5
Weighted Average Grant Date Fair Value, Cancelled \| $ / shares	24
Weighted Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 19.14

Stock Compensation - Schedule_5

Stock Compensation - Schedule of Estimated Fair Value of Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
After-tax contributions	$ 2,486	$ 1,686	$ 1,141
Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
After-tax contributions	$ 2,486	$ 1,686	$ 1,141
Shares of common stock purchased	244,125	123,019	43,685
Expected term (in years)	6 months	6 months	6 months
Risk-free interest rate	5%	1%	0.10%
Expected volatility	86.80%	74.40%	65.10%
Expected dividend yield	0%	0%	0%

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net loss	$ (341,973)	$ (290,509)	$ (363,872)
Net loss per share, basic	$ (2.79)	$ (2.59)	$ (3.82)
Net loss per share, diluted	$ (2.79)	$ (2.59)	$ (3.82)
Weighted average shares of common stock, basic	122,576,527	112,233,649	95,136,719
Weighted average shares of common stock, diluted	122,576,527	112,233,649	95,136,719

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Antidilutive Securities Excluded From Computation of Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	20,544,007	12,819,064	9,410,832
Options outstanding to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	15,610,586	11,050,735	8,719,627
Unvested and outstanding restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,398,017	1,566,760	691,205
Common stock issued upon milestone achievement [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,535,404	201,569

Acquisition of ZebiAI - Additio

Acquisition of ZebiAI - Additional Information (Detail) - USD ($)		12 Months Ended
	Apr. 22, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Incremental stock compensation expense recognized in connection with acquisition				$ 4,600,000
Fair value of contingent milestone payments and earnout payments		$ 13,206,000	$ 32,378,000	50,258,000
ZebiAI [Member]
Business Acquisition [Line Items]
Acquisition date	Apr. 22, 2021
Payment for upfront consideration	$ 20,000,000
Aggregate fair value consideration transferred	61,800,000
Milestone payments	$ 85,000,000
Incremental charges		0	0
Percentage of payment related to collaboration or other agreements	10%
Business combination contingent consideration liability, contingent earnout payments	$ 100,000,000
Consideration transferred	135,500,000
Loss on initial consolidation of VIE	$ 11,855,000
Acquisition-related costs		$ 0	$ 0
Contingent consideration payment description		The outstanding Contingent Milestone Payments are payable in shares of the Company's common stock based on a fixed amount assigned to each milestone and the volume weighted-average closing price of the Company’s common stock for a specified period prior to the milestone achievement.
ZebiAI [Member] \| General and Administrative Expense [Member]
Business Acquisition [Line Items]
Acquisition-related costs				$ 900,000
ZebiAI [Member] \| Common Stock [Member]
Business Acquisition [Line Items]
Issued shares of common stock	1,914,219
ZebiAI [Member] \| Milestone Payments [Member]
Business Acquisition [Line Items]
Fair value of contingent milestone payments and earnout payments	$ 42,400,000
ZebiAI [Member] \| Earnout Payments [Member]
Business Acquisition [Line Items]
Fair value of contingent milestone payments and earnout payments	$ 5,000,000

Acquisition of ZebiAI - Summary

Acquisition of ZebiAI - Summary of Net Assets Acquired Based on Estimated Fair Values (Detail) - ZebiAI [Member] $ in Thousands	Apr. 22, 2021 USD ($)
Business Acquisition [Line Items]
Acquired IPR&D asset	$ 123,000
Loss on initial consolidation of VIE	11,855
Assets obtained in asset acquisition	662
Liabilities assumed in asset acquisition	(2,330)
Intangible asset	2,300
Net acquired assets	$ 135,487

Collaboration and License Agree

Collaboration and License Agreement with Genentech, Inc. - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 29, 2024
Collaboration And License Arrangement [Line Items]
Collaboration revenue	$ 25,546,000	$ 1,381,000	$ 3,029,000
Accounts receivable		306,000
Contract asset		4,913,000
Genentech [Member]
Collaboration And License Arrangement [Line Items]
Contract asset		4,900,000
Cash received up on conditions satisfied	5,000,000
Genentech [Member] \| Current Liabilities [Member]
Collaboration And License Arrangement [Line Items]
Deferred revenue	0
Genentech [Member] \| Current Assets [Member]
Collaboration And License Arrangement [Line Items]
Accounts receivable	0
Contract asset	$ 0
Genentech [Member] \| Genentech Agreement [Member]
Collaboration And License Arrangement [Line Items]
Collaborative arrangement, purpose	In December 2020, the Company and Genentech, Inc. ("Genentech") entered into the Collaboration and License Agreement (as amended from time to time, the "Genentech Agreement"), which granted Genentech a license to develop and commercialize GDC-1971 (migoprotafib, formerly known as RLY-1971).
Non-refundable payments	$ 86,800,000
Milestones paid	25,000,000
Additional payments to be received upon achievement of other specified development commercialization and sales based milestones does not exercise option to participate in collaboration	675,000,000
Collaboration agreement transaction price	111,800,000
Development based milestone payments under agreement	0
Collaboration revenue	25,500,000	1,000,000	2,600,000
Genentech [Member] \| Genentech Agreement [Member] \| Subsequent Event [Member]
Collaboration And License Arrangement [Line Items]
Payments to be received upon achievement of other specified development commercialization and sales based milestones does not exercise option to participate in collaboration				$ 10,000,000
Genentech [Member] \| Genentech Agreement [Member] \| Transfer of License and Related Know-how [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	24,000,000	300,000	600,000
Genentech [Member] \| Genentech Agreement [Member] \| Research and Development Services [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	1,400,000	700,000	1,700,000
Genentech [Member] \| Genentech Agreement [Member] \| Transfer of Active Pharmaceutical Ingredient [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	100,000	$ 100,000	$ 300,000
Genentech [Member] \| Genentech Agreement [Member] \| Stand-alone Selling Prices ("SSP") [Member]
Collaboration And License Arrangement [Line Items]
Collaboration agreement transaction price	111,800,000
Genentech [Member] \| Genentech Agreement [Member] \| Stand-alone Selling Prices ("SSP") [Member] \| Transfer of License [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	107,600,000
Genentech [Member] \| Genentech Agreement [Member] \| Stand-alone Selling Prices ("SSP") [Member] \| Research and Development Services [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	3,800,000
Genentech [Member] \| Genentech Agreement [Member] \| Stand-alone Selling Prices ("SSP") [Member] \| Transfer of Active Pharmaceutical Ingredient [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue	$ 400,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 15, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Commitments and Contingencies Disclosure [Line Items]
Prepaid balance		$ 16,702,000	$ 12,110,000
Accrued expenses		14,890,000	22,703,000
DE Shaw Research [Member]
Commitments and Contingencies Disclosure [Line Items]
Research and development expense		9,500,000	9,400,000	$ 9,500,000
Prepaid balance		5,400,000	4,900,000
Accrued expenses		$ 0	$ 0
DE Shaw Research [Member] \| License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Research and development arrangement, annual fee	$ 9,900,000				$ 1,000,000
Research and development arrangement, term of contract					3 years
Research and development arrangement, expiration date	Aug. 16, 2025
Outstanding convertible preferred stock converted into common shares		3,281,253
Milestone payment due for first three targets		$ 7,300,000
Milestone payment due for each target after first three target		$ 6,300,000
Series A Preferred Stock [Member] \| DE Shaw Research [Member] \| Investment, Affiliated Issuer [Member] \| License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Shares held					9,999,999
Series C Preferred Stock [Member] \| DE Shaw Research [Member] \| Investment, Affiliated Issuer [Member] \| License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Shares held					1,557,875
Maximum [Member] \| DE Shaw Research [Member] \| License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Agreement renewal period		1 year
Potential development milestone payments		$ 7,300,000

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands	1 Months Ended		12 Months Ended
Leases - Additional Information (Details) $ in Thousands	Jun. 30, 2032	Apr. 30, 2029	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	May 31, 2021 ft²	Sep. 30, 2020 ft²	Jan. 31, 2018 ft²	Dec. 31, 2017 ft²
Operating Leased Assets [Line Items]
Operating lease option to terminate			true
Right of use asset			$ 57,969	$ 63,754
399 Binney Street [Member]
Operating Leased Assets [Line Items]
Land subject to ground leases \| ft²							1,824	44,807	44,336
Letter of credit			900
Fixed lease payments			4,300	4,100	$ 4,000
Right of use asset			$ 16,670	$ 18,828
Weighted-average remaining lease term			5 years 3 months 29 days	6 years 3 months 29 days
Weighted-average discount rate			10.40%	10.40%
399 Binney Street [Member] \| Forecast [Member]
Operating Leased Assets [Line Items]
Operating lease agreement expiration date		2029-04
Letter of credit expiration date		Apr. 30, 2029
60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Land subject to ground leases \| ft²						41,474
Letter of credit			$ 1,800
Fixed lease payments			5,000	$ 11,500	$ 0
Right of use asset			$ 41,299	$ 44,926
Weighted-average remaining lease term			8 years 6 months	9 years 6 months
Weighted-average discount rate			8%	8%
60 Hampshire Street [Member] \| Forecast [Member]
Operating Leased Assets [Line Items]
Operating lease agreement expiration date	2032-06
Letter of credit expiration date	Jun. 30, 2032

Leases - Schedule of Operating

Leases - Schedule of Operating Leases Presentation in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating Leased Assets [Line Items]
Operating lease assets	$ 57,969	$ 63,754
Operating lease liabilities	4,964	4,276
Operating lease liabilities, net of current portion	48,502	53,466
399 Binney Street [Member]
Operating Leased Assets [Line Items]
Operating lease assets	16,670	18,828
Operating lease liabilities	2,535	2,170
Operating lease liabilities, net of current portion	16,352	18,886
Total operating lease liabilities	18,887	21,056
60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Operating lease assets	41,299	44,926
Operating lease liabilities	2,429	2,106
Operating lease liabilities, net of current portion	32,150	34,580
Total operating lease liabilities	$ 34,579	$ 36,686

Leases - Summary of Operating L

Leases - Summary of Operating Lease Presentation in Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
399 Binney Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	$ 4,245	$ 4,243	$ 4,264
60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	6,487	3,239
Research and development expenses [Member] \| 399 Binney Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	3,631	3,350	3,262
Research and development expenses [Member] \| 60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	5,549	2,675
General and administrative expenses [Member] \| 399 Binney Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	614	893	$ 1,002
General and administrative expenses [Member] \| 60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
Operating lease costs	$ 938	$ 564

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
399 Binney Street [Member]
Operating Leased Assets [Line Items]
2024	$ 4,377
2025	4,503
2026	4,634
2027	4,768
2028	4,906
Thereafter	1,651
Total lease payments	24,839
Less: interest	(5,952)
Present value of operating lease liabilities	18,887	$ 21,056
60 Hampshire Street [Member]
Operating Leased Assets [Line Items]
2024	5,109
2025	5,257
2026	5,409
2027	5,565
2028	5,726
Thereafter	21,358
Total lease payments	48,424
Less: interest	(13,845)
Present value of operating lease liabilities	$ 34,579	$ 36,686

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
Income Taxes - Additional Information (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Income tax benefits	$ 0	$ 0	$ 0
Net operating loss carryforwards, federal	498,000,000	412,100,000
Net operating loss carryforwards, state	559,700,000	501,700,000
Increase in valuation allowance	69,300,000	87,800,000
Unrecognized tax benefits	$ 0	0
Description of income tax examinations	There are currently no pending tax examinations.
CARES Act, description of corporate tax payers	Corporate taxpayers may carryback NOLs originating during 2018 through 2020 for up to five years, which was not previously allowed under the 2017 Tax Act. The CARES Act also eliminates the 80% of taxable income limitations by allowing corporate entities to fully utilize NOL carryforwards to offset taxable income in 2018, 2019, or 2020. Taxpayers may generally deduct interest up to the sum of 50% of adjusted taxable income plus business interest income (30% limit under the 2017 Tax Act) for tax years beginning January 1, 2019 and 2020. The CARES Act allows taxpayers with alternative minimum tax credits to claim a refund in 2020 for the entire amount of the credits instead of recovering the credits through refunds over a period of years, as originally enacted by the 2017 Tax Act.
CARES Act, percentage of eliminates of taxable income	80%
CARES Act, maximum percentage of interest deducted by tax payers	50%
CARES Act, percentage of interest deducted by tax payers	30%
CARES Act, percentage of corporate charitable deduction limit	25%
CARES Act, period of qualified improvement property for cost-recovery	15 years
CARES Act, percentage of bonus depreciation	100%
Maximum [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryback period	5 years
Federal [Member]
Income Tax Disclosure [Line Items]
Income tax benefits	$ 0	0
Net operating loss carryforwards, subject to expiration	43,100,000
Net operating loss carryforwards, not subject to expiration	$ 454,900,000
Net operating loss carryforwards, beginning to expiring year	2035
Research and development tax credits, beginning to expiring year	2035
Research and development tax credit carryforwards	$ 38,900,000	25,900,000
State [Member]
Income Tax Disclosure [Line Items]
Income tax benefits	$ 0	0
Net operating loss carryforwards, beginning to expiring year	2035
Research and development tax credits, beginning to expiring year	2030
Research and development tax credit carryforwards	$ 8,500,000	$ 5,600,000

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Expected Income Tax (Benefit) Computed Using Federal Statutory Income Tax Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax computed at federal statutory rate	21%	21%	21%
State taxes, net of federal benefit	(3.70%)	6.50%	5.70%
Change in valuation allowance	(20.30%)	(30.20%)	(20.50%)
IPR&D	0%	0%	(7.00%)
R&D credit carryovers	4.50%	4.20%	2.20%
Stock compensation	(1.70%)	(2.10%)	(0.40%)
Permanent differences	0.20%	(0.60%)	(1.00%)
Total	0%	0%	0%

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating losses	$ 141,453	$ 119,688
Tax credit carryforwards	45,969	30,593
Capitalized R&D	90,273	55,303
Lease liability	12,914	18,307
Stock compensation	19,448	14,510
Intangibles	1,261	1,875
Depreciation and amortization	505	568
Other	263	7,270
Total gross deferred tax assets	312,086	248,114
Valuation allowance	(299,829)	(230,518)
Net deferred tax assets	12,257	17,596
Deferred tax liabilities
Operating lease assets	(12,257)	(17,596)
Total deferred tax liabilities	$ (12,257)	$ (17,596)

Employee Benefits - Additional

Employee Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Employer matching contribution	$ 2.6	$ 2.3	$ 1.2