C4 Therapeutics (CCCC) 10-K 24 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 15, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Trading Symbol	CCCC
Entity Registrant Name	C4 Therapeutics, Inc.
Entity Central Index Key	0001662579
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,738,862
Entity Public Float			$ 1,278,344,331
Entity File Number	001-39567
Entity Tax Identification Number	47-5617627
Entity Address, Address Line One	490 Arsenal Way
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Watertown
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02472
City Area Code	617
Local Phone Number	231-0700
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Auditor Firm ID	185
Auditor Name	KPMG LLP
Auditor Location	Boston, MA, United States
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive proxy statement for its 2021 Annual Meeting of Stockholders to be filed pursuant to Regulation 14A within 120 days of the end of the registrant’s fiscal year ended December 31, 2021 are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 76,124	$ 181,727
Marketable securities, current	233,155	189,962
Accounts receivable	5,716	4,484
Prepaid expenses and other current assets	10,694	4,836
Total current assets	325,689	381,009
Marketable securities, non-current	142,200
Property and equipment, net	3,108	3,323
Right-of-use asset	31,945	13,229
Restricted cash	3,279	2,577
Other assets	544
Total assets	506,765	400,138
Current liabilities:
Accounts payable	4,506	5,683
Accrued expenses and other current liabilities	13,606	9,524
Deferred revenue, current	31,800	27,603
Operating lease liability, current	1,334	1,042
Total current liabilities	51,246	43,852
Deferred revenue, net of current	24,368	53,617
Operating lease liability, net of current	30,777	11,826
Long-term debt—related party	10,768	10,052
Total liabilities	117,159	119,347
Commitments and contingencies (See Note 6 and Note 9)
Stockholders’ equity:
Preferred stock, par value of $0.0001 per share; 10,000,000 and no shares authorized, and no shares issued or outstanding as of December 31, 2021 and 2020, respectively
Common stock, par value of $0.0001 per share; 150,000,000 shares authorized, and 48,688,875 and 43,059,632 shares issued and outstanding as of December 31, 2021 and 2020, respectively	5	4
Additional paid-in capital	658,091	464,597
Accumulated other comprehensive (loss) income	(775)	13
Accumulated deficit	(267,715)	(183,823)
Total stockholders’ equity	389,606	280,791
Total liabilities and stockholders’ equity	$ 506,765	$ 400,138

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	48,688,875	43,059,632
Common stock, shares outstanding	48,688,875	43,059,632

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue from collaboration agreements	$ 45,785	$ 33,195	$ 21,381
Operating expenses:
Research and development	94,665	78,440	48,059
General and administrative	33,254	15,204	8,774
Total operating expenses	127,919	93,644	56,833
Loss from operations	(82,134)	(60,449)	(35,452)
Other (expense) income, net
Interest expense and amortization of long-term debt—related party	(2,145)	(1,229)
Interest and other income, net	387	393	2,157
Change in fair value of warrant liability—related party		(5,676)
Total other (expense) income, net	(1,758)	(6,512)	2,157
Loss before income taxes	(83,892)	(66,961)	(33,295)
Income tax benefit (expense)		626	(804)
Net loss	(83,892)	(66,335)	(34,099)
Unrealized (loss) gain on marketable securities	(788)	13
Comprehensive loss	(84,680)	(66,322)	(34,099)
Reconciliation of net loss to net loss attributable to common stockholders:
Net loss	(83,892)	(66,335)	(34,099)
Accrual of preferred stock dividends			(8,468)
Net loss attributable to common stockholders - basic and diluted	$ (83,892)	$ (66,335)	$ (42,567)
Net loss per share attributable to common stockholders - basic and diluted	$ (1.82)	$ (5.83)	$ (31.03)
Weighted-average common stock outstanding - basic and diluted	46,041,733	11,370,328	1,371,905

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Redeemable Convertible Preferred Stock
Beginning balance at Dec. 31, 2018	$ (79,750)		$ 3,639		$ (83,389)
Redeemable convertible preferred stock, Beginning balance, Shares at Dec. 31, 2018						113,145,900
Redeemable convertible preferred stock, Beginning balance at Dec. 31, 2018						$ 110,995
Beginning balance, Shares at Dec. 31, 2018		1,338,956
Exercise of stock options	274		274
Exercise of stock options, Shares		93,797
Stock-based compensation	1,642		1,642
Repurchase of common stock	(30)		(30)
Repurchase of common stock, Shares		(6,112)
Net loss	(34,099)				(34,099)
Ending balance at Dec. 31, 2019	(111,963)		5,525		(117,488)
Redeemable convertible preferred stock, Ending balance, Shares at Dec. 31, 2019						113,145,900
Redeemable convertible preferred stock, Ending balance at Dec. 31, 2019						$ 110,995
Ending balance, Shares at Dec. 31, 2019		1,426,641
Series B redeemable convertible preferred stock issuance, net of issuance costs of $4.5 million						$ 145,525
Series B redeemable convertible preferred stock issuance, net of issuance costs of $4.5 million, Shares						142,857,142
Initial public offering of common stock, net of issuance costs of $18.6 million	191,173	$ 1	191,172
Initial public offering of common stock, net of issuance costs of $18.6 million, Shares		11,040,000
Redeemable convertible preferred stock conversion upon closing of initial public offering	256,520	$ 3	256,517			$ (256,520)
Redeemable convertible preferred stock conversion upon closing of initial public offering, Shares		30,355,379				(256,003,042)
Warrant liability equity reclass.—related party	8,001		8,001
Exercise of stock options	887		887
Exercise of stock options, Shares		281,584
Stock-based compensation	3,432		3,432
Repurchase of common stock	(210)		(210)
Repurchase of common stock, Shares		(43,972)
Vested stock option settlement	(727)		(727)
Unrealized gain (loss) on investments	13			$ 13
Net loss	(66,335)				(66,335)
Ending balance at Dec. 31, 2020	280,791	$ 4	464,597	13	(183,823)
Ending balance, Shares at Dec. 31, 2020		43,059,632
Follow-on common stock offering, net of issuance costs of $11.3 million	169,465	$ 1	169,464
Follow-on common stock offering, net of issuance costs of $11.3 million, Shares		4,887,500
Shares issued upon warrant exercise - related party, Shares		256,038
Exercise of stock options	2,330		2,330
Exercise of stock options, Shares		474,850
Issuance of common stock under the 2020 ESPP	180		180
Issuance of common stock under the 2020 ESPP, Shares		6,640
Stock-based compensation	21,340		21,340
Unrealized gain (loss) on investments	(788)			(788)
Net loss	(83,892)				(83,892)
Other	180		180
Other, Shares		4,215
Ending balance at Dec. 31, 2021	$ 389,606	$ 5	$ 658,091	$ (775)	$ (267,715)
Ending balance, Shares at Dec. 31, 2021		48,688,875

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Series B Redeemable Convertible Preferred Stock
Issuance costs		$ 4.5
IPO
Issuance costs		$ 18.6
Follow-on Common Stock Offering
Issuance costs	$ 11.3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows used in operating activities:
Net loss	$ (83,892)	$ (66,335)	$ (34,099)
Adjustments to reconcile net loss to cash (used in) provided by operating activities:
Stock-based compensation expense	21,512	3,432	1,642
Depreciation and amortization	1,492	1,617	1,595
Accretion of discount (premium) on investments	1,879	(95)	334
Reduction in carrying amount of right-of-use asset	1,415	1,224	1,144
Amortization of debt discount—related party	719	409
Change in fair value of warrant liability		5,676
Gain on disposal of fixed assets			16
Changes in operating assets and liabilities:
Accounts receivable	(1,232)	139	81,815
Prepaid expenses and other current and long-term assets	(6,116)	(3,257)	(814)
Accounts payable	(1,179)	467	4,231
Accrued expenses and other current liabilities	4,377	2,558	3,719
Operating lease liability	(888)	(881)	(734)
Deferred revenue	(25,052)	(12,203)	(3,235)
Net cash (used in) provided by operating activities	(86,965)	(67,249)	55,614
Cash flows used in investing activities:
Proceeds from maturities of marketable securities	349,681	104,000	78,666
Purchase of marketable securities	(537,740)	(293,855)	(79,000)
Purchases of property and equipment	(1,277)	(650)	(1,349)
Proceeds from sale of property and equipment			63
Net cash used in investing activities	(189,336)	(190,505)	(1,620)
Cash flows provided by financing activities:
Proceeds from follow-on offering, net of issuance costs paid of $11.3 million	169,465
Proceeds from exercises of stock options	2,330	887	274
Proceeds from initial public offering, net of underwriting discount of $14.7 million		195,074
Payment of initial public offering costs	(286)	(3,606)
Proceeds from issuance of Series B shares, net of issuance costs of $4.5 million		145,525
Proceeds from long-term debt and warrant—related party, net of issuance costs of $0.5 million		11,973
Repurchase of common stock		(194)	(30)
Vested stock option settlement		(727)
Other	(109)
Net cash provided by financing activities	171,400	348,932	244
Net change in cash, cash equivalents and restricted cash	(104,901)	91,178	54,238
Cash, cash equivalents and restricted cash at beginning of period	184,304	93,126	38,888
Cash, cash equivalents and restricted cash at end of period	79,403	184,304	93,126
Reconciliation of cash, cash equivalents and restricted cash:
Cash, cash equivalents and restricted cash at end of period	79,403	184,304	93,126
Less: restricted cash	(3,279)	(2,577)	(2,577)
Cash and cash equivalents at end of the year	76,124	181,727	90,549
Supplemental disclosure of cash flow information:
Cash paid for interest	1,308	820
Cash paid for taxes		143	1,088
Supplemental disclosures of non-cash investing and financing activities:
Operating lease liabilities arising from obtaining right-of-use assets	$ 20,131
Conversion of redeemable convertible preferred stock to common stock upon closing of the initial public offering		256,520
Warrant liability reclassification to equity		8,001
Initial public offering costs in accounts payable and accrued expenses		$ 296
Capital expenditures in accounts payable			172
Stock option repurchases included in accrued expenses			$ 16

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)
Stock issuance costs	$ 11.3
Long-term debt and warrant, net of issuance costs	0.5
Underwriting discount	14.7
Series B Shares
Stock issuance costs	$ 4.5

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	Note 1. Nature of the business C4 Therapeutics, Inc., or, together with its subsidiary, the Company, is a clinical-stage biopharmaceutical company dedicated to advancing targeted protein degradation science to develop a new generation of small-molecule medicines to transform how disease is treated. C4T leverages its proprietary technology platform, TORPEDO ( T arget OR iented P rot E in D egrader O ptimizer), to efficiently design and optimize small-molecule medicines that harness the body’s natural protein recycling system to rapidly degrade disease-causing protein, offering the potential to overcome drug resistance, drug undruggable targets and improve patient outcomes. C4T uses the TORPEDO platform to advance multiple targeted oncology programs to the clinic while expanding the platform to deliver the next wave of medicines for difficult-to-treat diseases. Liquidity and capital resources Since its inception, the Company’s primary activities have been focused on research and development activities, building the Company’s intellectual property, recruiting personnel and raising capital to support these activities. To date, the Company has funded its operations primarily with proceeds received from the sales of redeemable convertible preferred stock, public offerings of the Company’s common stock, through its collaboration agreements, and debt financing. The Company has incurred recurring losses since its inception, including net losses of $83.9 million, $66.3 million, and 34.1 million, for the years ended December 31, 2021, 2020, and 2019, respectively. In addition, as of December 31, 2021, the Company had an accumulated deficit of $267.7 million. To date, the Company has not generated any revenue from product sales as none of its product candidates has been approved for commercialization. The Company expects to continue to generate operating losses for the foreseeable future. As further discussed in Note 10, Stockholders’ equity , on October 6, 2020, the Company completed its initial public offering, or the IPO. The net proceeds to the Company from the IPO were $191.2 million, after deducting expenses and underwriting discounts and commissions. Upon the closing of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock automatically converted into 30,355,379 shares of common stock. In June 2021, the Company completed a follow-on public offering. The net proceeds to the Company from the follow-on public offering were $169.5 million, after deducting expenses and underwriting discounts and commissions. The Company expects that its cash, cash equivalents and marketable securities of $451.5 million as of December 31, 2021 will be sufficient to fund its operations for at least the next twelve months from the date of issuance of these consolidated financial statements. Reverse stock split On September 25, 2020, the Company effected a one-for-8.4335 reverse stock split of its issued and outstanding common stock and stock options, and a proportional adjustment to the existing conversion ratios for the Company’s redeemable convertible preferred stock. Accordingly, all issued and outstanding common stock, options to purchase common stock and per share amounts contained in the consolidated financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented, except as otherwise stated. Risks and uncertainties The Company is subject to risks common to other life science companies in the early development stage including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology and intellectual property, ability to raise additional financing and compliance with the Food and Drug Administration, or the FDA, and other government regulations. If the Company does not successfully advance its programs into and through human clinical trials and commercialize any of its product candidates either directly or through collaborations with other companies, the Company may be unable to produce product revenue or achieve profitability. There can be no assurance that the Company’s research and development efforts will be successful, adequate protection for the Company’s intellectual property will be obtained, any products developed will obtain necessary government regulatory approval, or 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 pharmaceutic al and biotechnology companies.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of significant accounting policies Basis of presentation The Company has prepared the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States of America, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. Principles of consolidation The Company’s consolidated financial statements include the accounts of C4 Therapeutics, Inc. and its wholly owned subsidiary C4T Securities Corporation, a Massachusetts securities corporation. All significant intercompany balances and transactions have been eliminated in consolidation. Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. This process may result in actual results differing materially from those estimated amounts used in the preparation of the consolidated financial statements if these results differ from historical experience or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, amounts and timing of revenues recognized under the Company’s research and development collaboration arrangements, prepaid and accrued research and development expense, incremental borrowing rate used in the measurement of lease liability, and estimated volatility used in fair valuation of stock options. The Company assesses estimates on an ongoing basis; however, actual results could materially differ from those estimates. Segments Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purpose of allocating resources. All of the Company’s long-lived assets are held in the United States. Cash and cash equivalents The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company’s cash equivalents are measured at fair value on a recurring basis. Marketable securities The Company classifies marketable securities with a remaining maturity when purchased of greater than three months as available-for-sale. Marketable securities with a remaining maturity date greater than one year are classified as non-current assets. Restricted cash Restricted cash consists of cash placed in separate restricted bank account as required under the terms of the Company’s lease agreements for its Watertown, Massachusetts facility, as further described within Note 6, Leases Concentrations of credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash, cash equivalents, marketable securities, and restricted cash. The Company may maintain deposits in financial institutions in excess of government insured limits. The Company believes that it is not exposed to significant credit risk as its deposits are held at financial institutions that management believes to be of high credit quality and the Company has not experienced any losses on these deposits. Additionally, t he Company has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company maintains its funds in accordance with its investment policy, which defines allowable investments, specifies credit quality standards and is designed to limit credit exposure to any single issuer. Fair value of financial instruments ASC Topic 820, Fair Value Measurement • Level 1—Quoted market prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. • Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company evaluates transfers between levels at the end of each reporting period. Property and equipment Property and equipment are recorded at cost. Expenditures for repairs and maintenance are expensed as incurred. When assets are retired or disposed of, the assets and related accumulated depreciation are derecognized from the accounts, and any resulting gain or loss is included in the determination of net loss. Depreciation on equipment is calculated using the straight-line method over the estimated useful lives of the assets as follows: Asset category Estimated useful life Laboratory equipment 5 years Computer equipment 3 years Office equipment, furniture and fixtures 5 years Leasehold improvements Lesser of useful life or remaining lease term Leases The Company accounts for leases in accordance with ASC Topic 842, Leases Certain adjustments to the right-of-use asset may be required for items such as incentives received. The Company typically only includes an initial lease term in its assessment of a lease arrangement; options to renew a lease are not included in the assessment unless there is reasonable certainty that the Company will renew. Impairment of long-lived assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceed the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Commitments and contingencies Liabilities for loss contingencies arising from claims, assessments, litigation, fines and penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred. Revenue recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers The Company enters into collaboration and licensing agreements with strategic partners, which are within the scope of ASC 606, under which it may exclusively license rights to research, develop, manufacture, and commercialize its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: (1) non-refundable, upfront license fees; (2) reimbursement of certain costs; (3) customer option fees for additional goods or services; (4) development milestone payments, (5) regulatory and commercial milestone payments; and (6) royalties on net sales of licensed products. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use its 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; (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above; and (d) the contract term and pattern of satisfaction of the performance obligations under step (v) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts due to the Company for satisfying the revenue recognition criteria or that are contractually due based upon the terms of the collaboration agreements are recorded as accounts receivable in the Company’s consolidated balance sheet. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Upfront license fees If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, manufacturing, and commercialization capabilities of the customer; the retention of any key rights by the Company; and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promises, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company exercises judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised. If an option is not exercised and the target is terminated, the Company will accelerate and recognize all remaining revenue related to the material right performance obligation. Research and development services The promises under the Company’s collaboration agreements may include research and development services to be performed by the Company for or on behalf of the customer. Payments or reimbursements resulting from the Company’s research and development efforts are recognized as the services are performed and presented on a gross basis because the Company is the principal for such efforts. Reimbursements from and payments to the customer that are the result of a collaborative relationship with the customer, instead of a customer relationship, such as co-development activities, are recorded as a reduction to research and development expense. Milestone payments At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. For further discussion of accounting for collaboration revenues, see Note 8, License Agreements. Research and development Research and development costs are expensed as incurred. Research and development costs include salaries, stock-based compensation and other employee benefit expenses, lab related supplies 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 research and development activities. Costs associated with licenses of technology are expensed as incurred and are included in research and development expense in the consolidated statement of operations and comprehensive loss. As part of the process of preparing the consolidated financial statements, the Company is required to estimate their accrued research and development expenses. The Company makes estimates of the accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known at that time. In addition, there may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense in which case such amounts are reflected as prepaid expenses and other current assets. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual or the amount of prepaid expenses accordingly. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized in prepaid expenses and other current assets. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Stock-based compensation The Company measures and recognizes stock-based compensation expense based on the grant date fair value of equity awards measured using the Black-Scholes option pricing model. The Black-Scholes option pricing model estimates the fair value of the equity award using the expected term, expected volatility, risk-free interest rate, dividend rate, and the fair value of the common stock underlying the stock-based award. The Company estimates the expected life stock options using the “simplified” method, whereby, the expected life equals the arithmetic average of the vesting term and the original contractual term of the option. Due to the lack of sufficient company-specific historical and implied volatility data, the Company has based its computation of expected volatility on the historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The risk-free interest rates for periods within the expected life of the option were based on the U.S. Treasury yield curve in effect during the period the options were granted. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company recognizes forfeitures as they occur. Prior to the IPO, the fair value of common stock underlying stock-based awards was based on an estimate at each grant date by the Company’s board of directors. The Company determined the estimated per share fair value of its common stock at various dates considering contemporaneous and retrospective valuations in accordance with the guidance outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation Subsequent to the IPO, the fair value of the common stock underlying shared based awards is the quoted market price of the Company’s common stock on the date of the grant. The Company recognizes stock-based compensation expense on a straight-line basis over the requisite service period of the awards for service-based awards, which is generally the vesting period. Stock-based compensation expense is classified in the consolidated statement of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. Warrant liability expense In June 2020, the Company issued a warrant to purchase shares of its Series B redeemable convertible preferred stock. Upon issuance, the Company classified the warrant as a liability on its consolidated balance sheet and remeasured the fair value of the warrant liability at each reporting date using the Black-Scholes option pricing model. The Black-Scholes option pricing model incorporates assumptions and estimates to value the warrant. Estimates and assumptions impacting the fair value measurement include the fair value per share of the underlying redeemable convertible Series B Preferred Stock or common stock issuable upon exercise of the warrant, remaining contractual term of the warrant, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying redeemable convertible preferred stock or common stock. Changes in the fair value of the warrant liability at each reporting period was recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Upon completion of the IPO, the warrant converted into a warrant to purchase shares of the Company’s common stock, as described in Note 9, Long-term debt and warrant liability Income taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequence of events that have been recognized in the consolidated financial statements or the Company’s tax returns. Under this method, deferred tax assets and liabilities are determined based on the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established. The Company accounts for uncertain tax positions recognized in the consolidated financial statements by prescribing a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, which are considered appropriate as well as the related net interest and penalties. Comprehensive loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) which includes certain changes in equity that are excluded from net loss. The Company’s only element of other comprehensive income is unrealized gains and losses on marketable securities. Net loss per share Basic net loss per share and diluted net loss per share are computed using the weighted-average number of shares of common stock outstanding for the period. Net loss per share attributable to common stockholders is calculated using the two-class method, which is an earnings allocation formula that determines net loss per share for the holders of shares of the Company’s common stock and participating securities. The Company’s preferred stock contained participation rights in any dividend paid by the Company and was deemed to be a participating security. The participating securities do not include a contractual obligation to share in losses of the Company and are not included in the calculation of net loss per share in the periods in which a net loss is recorded. Diluted net loss per share is computed using the more dilutive of (a) the two-class method or (b) the if-converted method. The Company allocated earnings first to preferred stockholders based on dividend rights and then to common and preferred stockholders based on ownership interests. The weighted-average number of shares of common stock included in the computation of diluted net loss gives effect to all potentially dilutive common stock equivalent shares, including outstanding stock options and Preferred Stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Going concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash, cash equivalent, and marketable securities balances. Recently adopted accounting standards In December 2019, the FASB issued Accounting Standards Update, or ASU, No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, or Recently issued accounting standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 3. Fair value measurements The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values as of December 31, 2021 (in thousands): Fair Value Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 59,162 $ 59,162 $ — $ — Corporate debt securities 11,649 — 11,649 — U.S. Treasury securities 5,000 — 5,000 — Marketable securities: Corporate debt securities 308,300 — 308,300 — U.S. government debt securities 37,883 — 37,883 — U.S. Treasury securities 29,172 — 29,172 — Total cash equivalents and marketable securities $ 451,166 $ 59,162 $ 392,004 $ — The following table sets forth the fair value of the Company’s financial assets by level within the fair value hierarchy at December 31, 2020 (in thousands): Fair Value Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 180,078 $ 180,078 $ — $ — Marketable securities: U.S. Treasury securities 189,962 — 189,962 — Total cash equivalents and marketable securities $ 370,040 $ 180,078 $ 189,962 $ — The Company classifies its money market funds, which are valued based on quoted market prices in active markets, with no valuation adjustment, as Level 1 assets within the fair value hierarchy. Marketable securities consist of U.S. Treasury securities, U.S. government debt securities, and corporate debt securities, all of which are classified as available-for-sale pursuant to ASC 320, Investments – Debt and Equity Securities

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2021
Marketable Securities [Abstract]
Marketable Securities	Note 4. Marketable securities Marketable securities at December 31, 2021 consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities: Corporate debt securities $ 308,952 $ 1 $ (653 ) $ 308,300 U.S. government debt securities 37,988 — (105 ) 37,883 U.S. Treasury securities 29,190 — (18 ) 29,172 Total marketable securities, current and non-current $ 376,130 $ 1 $ (776 ) $ 375,355 Marketable securities at December 31, 2020 consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities U.S. Treasury securities $ 189,949 $ 13 $ — $ 189,962 Total marketable securities, current $ 189,949 $ 13 $ — $ 189,962 As of December 31, 2021, the Company held 123 marketable securities, with an aggregate fair value of $365.5 million, in an unrealized loss position. There were no individual securities that were in a significant unrealized loss position as of , and the Company did not record an allowance for credit losses as of related to these securities. Further, given the lack of significant change in the credit risk of these investments, the Company did no t recognize any other-than-temporary impairment losses.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Property and Equipment	Note 5. Property and equipment Property and equipment consisted of the following (in thousands): As of December 31, 2021 2020 Property and equipment Laboratory equipment $ 8,276 $ 7,207 Furniture and fixtures 805 805 Leasehold improvements 541 541 Computer equipment 223 223 Office equipment 179 179 Total property and equipment 10,024 8,955 Less: accumulated depreciation (6,916 ) (5,632 ) Total property and equipment, net $ 3,108 $ 3,323 Depreciation expense related to property and equipment was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Depreciation expense $ 1,492 $ 1,617 $ 1,595

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Note 6. Leases In July 2017, the Company entered into a lease of office and laboratory space for its headquarters in Watertown, Massachusetts, or the Watertown Lease. The Watertown Lease had a non-cancelable term of ten years with an option to extend for one additional five-year period and is subject to rent escalation throughout the term. Additionally, the Watertown Lease required the Company to provide collateral, which was recorded as restricted cash on the consolidated balance sheets. The Watertown Lease commenced in April 2018. The Watertown Lease was classified as an operating lease and, upon the commencement in April 2018, the Company recorded a lease liability of $15.1 million and a right-of-use asset of $16.7 million, which is inclusive of $1.5 million of construction costs funded by the Company. In initially calculating the lease liability and the right-of-use asset, the Company did not include the additional five-year period option as management did not believe there was reasonable certainty that the Company would exercise the option. In addition to rent, the Company is also responsible for paying its pro rata share of costs incurred for common area maintenance, real estate taxes and property insurance related to the leased space, which are accounted for as variable lease costs. In November 2021, the Company entered into an amendment to the Watertown Lease, or the Amended Lease. The Amended Lease serves to extend the lease term of the Company’s existing leased space, or the Existing Leased Space, and provides additional office and laboratory space, or the Newly Leased Space. The Amended Lease commenced in January 2022 and the Company’s obligation to pay rent on the Newly Leased Space commencing two months after the lease commencement date for the Newly Leased Space and terminating in January 2032, which is 10 years from the rent commencement date for the Newly Leased Space. The Amended Lease is subject to fixed rate rent escalations, provides for up to $2.6 million in tenant improvements, and provides an option for the Company to extend the lease term of the Amended Lease for one additional five-year Accounting for the amended lease As the Amended Lease extends the term of the Existing Leased Space and provides access to the Newly Leased Space, in accordance with the provisions of ASC 842, the Company accounted for the Amended Lease as two separate contracts: 1) modification of the existing lease agreement to extend the lease term of the Existing Leased Space, and 2) new lease agreement for the right-of-use of the Newly Leased Space. As the Company maintained control of the Existing Leased Space upon execution of the Amended Lease, the Company recorded an increase in right-of-use asset and lease liability of $20.1 million related to the new rental payments during the extended term and current incremental borrowing rate of the Existing Leased Space upon execution of the Amended Lease. The calculation of the lease liability and the right-of-use asset of the Existing Leased Space does not include the additional five-year period option as the Company does not believe there is reasonable certainty that the option will be exercised. As the lease for the Newly Leased Space did not commence prior to December 31, 2021, the Company did not record a right-of-use asset or the corresponding lease liability for the Newly Leased Space on the accompanying consolidated balance sheets as of December 31, 2021. The undiscounted lease payments for the Newly Leased Space are expected to be $62.1 million, which is not included in the future lease payments table below but will be included in the financial statements for periods ending after the lease commencement date for the Newly Leased Space. As stated above, the Amended Lease provides for up to $2.6 million of tenant improvement allowance. As of December 31, 2021, no tenant improvement allowances have been recorded as the improvements will begin in 2022. The elements of lease costs were as follows (in thousands): Years Ended December 31, 2021 2020 2019 Lease cost: Operating lease cost $ 2,686 $ 2,550 $ 2,550 Variable lease cost 857 1,066 1,020 Total lease cost $ 3,543 $ 3,616 $ 3,570 The following table summarizes the lease term and incremental borrowing rate applied in arriving at the lease liability: As of December 31, 2021 2020 Remaining lease term 10.2 years 7.3 years Incremental borrowing rate 5.2 % 10.0 % Future lease payments under non-cancelable leases as of December 31, 2021 for each of the years ending December 31 are as follows (in thousands): Undiscounted lease payments*: 2022 $ 2,994 2023 3,491 2024 3,596 2025 3,704 2026 3,815 Thereafter 25,085 Total undiscounted lease payments 42,685 Less: imputed interest (10,574 ) Total operating lease liability as of December 31, 2021 $ 32,111 *As stated above, this table does not include lease payments for the Newly Leased Space under the Amended Lease as the commencement date is subsequent to December 31, 2021.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Note 7. Accrued expenses and other current liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): As of December 31, 2021 2020 Accrued expenses and other current liabilities: Accrued research and development $ 6,863 $ 3,799 Accrued compensation and benefits 5,084 3,724 Accrued professional fees 1,246 1,532 Other 413 469 Total accrued expenses and other current liabilities $ 13,606 $ 9,524

Collaboration and License Agree

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2021
Collaboration And License Agreements [Abstract]
Collaboration and License Agreements	Note 8. Collaboration and license agreements Roche Collaboration and License Agreement In March 2016, the Company entered into a license agreement with Roche, which was amended in June 2016 and amended further in March 2017. The Company amended and restated that agreement (as so amended) in December 2018. This amended and restated agreement is referred to as the Roche Agreement. Under the Roche Agreement, the Company and Roche agreed to collaborate in the research, development, manufacture and commercialization of target-binding degrader medicines using the Company’s proprietary TORPEDO platform for the treatment of cancers and other indications. In November 2020, the Company signed a further amendment, which provided that the parties would develop up to five potential targets, with Roche maintaining its option rights to license and commercialize products directed to those targets. The November 2020 amendment also provides a mechanism through which the Company and Roche can mutually agree to terminate the Roche Agreement on a target-by-target basis by the entry into a mutual target termination agreement. In November 2020, through the entry into this amendment, the Company and Roche mutually agreed to terminate the Roche Agreement as to the target EGFR. As a result, Roche is now free to pursue the target EGFR in the Roche Field and the Company free to pursue the target EGFR in the C4T Field. In November 2021, the Company and Roche mutually agreed to terminate the Roche Agreement as to the target BRAF, converting BRAF into a proprietary program for us. As a result, Roche is now free to pursue the target BRAF in the Roche Field and the Company is now free to pursue the target BRAF in the C4T Field. Under the terms of the Roche Agreement, the Company is responsible for conducting preclinical research and development activities for a number of targets selected by Roche in accordance with a target selection and replacement procedure set forth in the agreement. The Company is also responsible for conducting Phase 1 clinical trials for products directed to certain targets and for manufacturing activities in connection with the applicable research plans, subject to Roche’s right to assume manufacturing responsibilities at pre-defined times. The Company and Roche each share in the costs of these research activities. Under the Roche Agreement, the Company granted Roche an exclusive option to obtain an exclusive, worldwide license, with the right to sublicense through multiple tiers to develop and commercialize products directed at each target that is subject to the collaboration. Upon the exercise of its option for a particular target, Roche is responsible for the manufacture, development and commercialization of products directed to that target, at its sole expense. However, the Company has the option to co-develop products directed to certain targets, in which case the Company would be responsible for a portion of the development costs associated with such co-developed products and eligible to receive increased royalties on sales of such co-developed products. The Company also has an option to co-detail products for which it has exercised its co-development option. If the Company exercises its co-detail option, it will be responsible for a portion of the co-detailing costs. The Company generally has the right to opt out of these co-development and co-detailing activities. Upon signing the Roche Agreement, the Company received upfront consideration of $40.0 million from Roche. In addition, the Company receives annual research plan payments of $1.0 million for up to three years for each active research plan. For certain targets, Roche is required to pay the Company fees of $2.0 million and $3.0 million upon the progression of targets to the lead series identification achievement and good laboratory practice toxicology study phase, respectively. If Roche exercises its option right for a target, Roche is obligated to pay exercise fees ranging from $7.0 million to $20.0 million depending on the target. For each target option exercised by Roche, the Company is eligible to receive milestone payments ranging from $260 million to $275.0 million upon the achievement of certain research, development and commercial milestones with respect to corresponding products, subject to certain reductions and exclusions based on intellectual property coverage. Roche is also required to pay the Company up to $150.0 million per target in one-time sales-based milestone payments upon the achievement of specified levels of net sales of a product directed to such target. Finally, Roche is required to pay the Company tiered royalties ranging from the mid-single digits to mid-teen percentages on net sales of products sold by Roche pursuant to its exercise of its option rights, subject to certain reductions. For sales of products for which the Company exercises its co-development right, the applicable royalty rates will be increased by a low-single digit percentage. The collaboration is managed by a joint research committee. The Company has control over the committee and may terminate the Roche Agreement on a target-by-target or product-by-product basis under several scenarios, upon at least 90 days’ prior written notice. Roche Agreement accounting At commencement, t participation on joint research committee were identified as promised services. However, the Company determined that the research and development license and research and development services were not distinct from one another, and participation on the joint research committee was determined to be quantitatively and qualitatively immaterial. As of December 31, 2021, the total transaction price of $65.3 million is allocated to the performance obligations based on their relative standalone selling price. The allocated transaction price is recognized as revenue in one of two ways: • Research and development targets: The Company recognizes the portion of the transaction price allocated to each of the research and development performance obligations as the research and development services are provided, using an input method, in proportion to costs incurred to date for each research development target as compared to total costs incurred and expected to be incurred in the future to satisfy the underlying obligation related to said research and development target. The transfer of control occurs over this period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. • Option rights: The transaction price allocated to the options rights, which are considered material rights, is recognized in the period that Roche elects to exercise or elects to not exercise its option right to license and commercialize the underlying research and development target. The following table summarizes the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2021 (in thousands): Transaction Price Allocated Transaction Price Unsatisfied Performance obligations: Research and development targets $ 58,628 $ 26,996 Option rights 6,694 3,488 Total $ 65,322 $ 30,484 Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded as deferred revenue on the Company’s consolidated balance sheet. As described above, in November 2021, the Company and Roche mutually agreed to terminate the Roche Agreement as to the target BRAF. Upon termination, the Company recognized all previously unrecognized transaction price allocated to the BRAF research and development target and option right of $12.6 million as revenue from collaboration agreements. Biogen Collaboration Research and License Agreement In December 2018, the Company entered into a collaboration research and license agreement, or the Biogen Agreement, with Biogen MA, Inc., or Biogen, which was amended in February 2020. Pursuant to the terms of the Biogen Agreement, the Company and Biogen agreed to collaborate on research activities to develop novel treatments in the field of target protein degradation, or TPD, using the Company’s degrader technology. Under the terms of the Biogen Agreement, the Company will initially develop TPD therapeutics that utilize degrader technology for up to five target proteins over a period of 54 months, ending in June 2023. On a target-by-target basis, after successful completion of a defined target evaluation period, Biogen assumes full rights and responsibility to each degrader to meet certain criteria against a target. Biogen also has the option to pay an additional $62.5 million to extend the contract for four additional years and select up to five additional targets for development. In exchange for the non-exclusive research license from Biogen, as well as a $45.0 million nonrefundable upfront payment, the Company has granted a license to develop, commercialize and manufacture products related to each of the targets (which is contingent on not cancelling the contract), performs initial research services for drug discovery, has provided a non-exclusive research and commercial license to its intellectual property and participates on the joint steering committee, or the Biogen JSC. The Company is also obligated to participate in early research activities for other potential targets or sandbox activities, at Biogen’s election up to a maximum amount; any work performed for these services is reimbursed by Biogen, and Biogen reimburses the Company for certain full-time equivalent, or FTE, costs. The Company’s obligations under the sandbox activities are completed as of August 31, 2021. Biogen is also required to pay the Company up to $35.0 million per target in development milestones and $26.0 million per target in one-time sales-based payments for the first product to achieve certain levels of net sales. In addition, Biogen is required to pay the Company royalties on a licensed product-by-licensed product basis, on worldwide net product sales. The collaboration is managed by the Biogen JSC, which Biogen has control over, and Biogen may terminate the Biogen Agreement on a target-by-target or product-by-product basis under several scenarios, upon at least 90 days’ prior written notice. Biogen Agreement accounting The Company recognizes revenue under the Biogen Agreement from two types of services: 1) research and development services, and 2) sandbox activities, which are discovery-type research services. • Research and development services: The Company identified one performance obligation at the outset of the Biogen Agreement, representing a combined performance obligation consisting of (1) the licenses, (2) the research activities for the target evaluation phase for all five targets and (3) the joint research plan phase for each target. The Company determined that the licenses and research activities were not distinct from one another, as the licenses have limited value without the performance of the research activities by the Company. Participation on the Biogen JSC to oversee the research activities and the technology transfer associated with the Biogen License Agreement were determined to be quantitatively and qualitatively immaterial and therefore are excluded from performance obligations. The Company recognizes the transaction price allocated to this performance obligation as the research and development services are provided, using an input method, in proportion to costs incurred to date for each research development target as compared to total costs incurred and expected to be incurred in the future to satisfy the underlying obligation related to said research and development target. The transfer of control occurs over this period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. • Sandbox activities: Biogen had the option to fund sandbox activities in exchange for consideration at market rates, whereby the Company would perform discovery-type research at Biogen’s election to develop other potential targets that may be used as replacement targets for the initially nominated targets or two additional targets under the Biogen Agreement. Revenues earned under this option were recognized as services were performed and were not included in the transaction price allocated to the performance obligation described above. The Company recognized FTE reimbursement received for sandbox activities as revenue as incurred each quarter. As noted above, sandbox activities fully concluded on August 31, 2021. As of December 31, 2021, total transaction price of $55.0 million is allocated to the research and development services performance obligation and $30.6 million of the allocated transaction price remains unsatisfied. The transaction price as of December 31, 2021 includes $6.0 million of milestones earned during the year ended December 31, 2021 and $4.0 million of milestones earned during the year ended December 31, 2020. Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded in deferred revenue on the Company’s consolidated balance sheet. Calico Collaboration and License Agreement In March 2017, the Company entered into a collaboration and license agreement, or the Calico Agreement, with Calico Life Sciences LLC, or Calico, whereby the Company and Calico agreed to collaborate to develop and commercialize small molecule protein degraders for diseases of aging, including cancer, for a five-year Under the terms of the Calico Agreement, the Company will initially develop and commercialize small molecule protein degraders for up to five target proteins over the research term. On a target-by-target basis, after successful completion of a defined target evaluation period, Calico has an exclusive option to pursue further pre-clinical development and commercialization via a joint research plan for each target. Under the Calico Agreement, Calico paid an upfront amount of $5.0 million and certain annual payments totaling $5.0 million through June 30, 2020 and pays target initiation fees and reimburses the Company for a number of FTEs, depending on the stage of the research, at specified market rates. Upon completion of the required discovery research and development services on any target, Calico is entitled to pursue commercial development of products related to that target. The Company will perform initial research services for drug discovery and preclinical development, provide a non-exclusive research and commercial license to its IP and will participate on the Calico joint research committee, or the Calico JRC. For each target, the Company is eligible to receive up to $132.0 million in potential research, development and commercial milestone payments, on sales of all products resulting from the collaboration efforts. Calico is also required to pay the Company up to $65.0 million in one-time sales-based payments for the first product to achieve certain levels of net sales. In addition, Calico is required to pay the Company royalties, at percentages in the mid-single digits, on a licensed product-by-licensed product basis, on worldwide net product sales. The Calico Agreement is managed by the Calico JRC. Calico has control over the Calico JRC and may terminate the Calico Agreement on a target-by-target or product-by-product basis under several scenarios, upon prior written notice. In August 2021, the Company provided Calico with an option to extend the research term with respect to a certain program for up to a one-year Calico Agreement accounting The Company identified one performance obligation at the outset of the Calico Agreement, which consists of: (1) the non-exclusive license and (2) the research activities for the target evaluation phase for five targets and the joint research plan phase for two targets. The Company determined that the license and research activities were not distinct from one another, as the license has limited value without the performance of the research activities by the Company. The transaction price consists of the upfront amount, the committed anniversary payments, the target initiation fees related to the targets nominated at the execution of the Calico Agreement, and the extension payment upon exercise of the extension option discussed above. Initially, the Company amortized the transaction price on a straight-line basis over the initial five-year six-year As of December 31, 2021, total transaction price of $13.0 million is allocated to the research and development services performance obligation and $2.7 million of the allocated transaction price remains unsatisfied. Amounts due to the Company that have not yet been received are recorded as accounts receivable and amounts received that have not yet been recognized as revenue are recorded in deferred revenue on the Company’s consolidated balance sheet. Summary of revenue recognized from collaboration agreements Revenue from collaboration agreements was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Revenue from collaboration agreements: Roche Agreement $ 19,379 $ 9,051 $ 6,409 Biogen Agreement 15,720 9,913 2,432 Calico Agreement 10,686 14,231 12,540 Total revenue from collaboration agreements $ 45,785 $ 33,195 $ 21,381 Supplemental information related to the collaboration and license agreements consisted of the following in the Company’s consolidated balance sheet as of December 31, 2021 (in thousands): Accounts Receivable Deferred Revenue, Current Deferred Revenue, Net of Current Deferred Revenue, Total Supplemental information: Roche Agreement $ 1,215 $ 5,601 $ 17,215 $ 22,816 Biogen Agreement 3,000 24,032 6,611 30,643 Calico Agreement 1,501 2,167 542 2,709 Total $ 5,716 $ 31,800 $ 24,368 $ 56,168 Supplemental information related to the collaboration and license agreements consisted of the following in the Company’s consolidated balance sheet as of December 31, 2020 (in thousands): Accounts Receivable Deferred Revenue, Current Deferred Revenue, Net of Current Deferred Revenue, Total Supplemental information: Roche Agreement 750 11,238 26,991 38,229 Biogen Agreement 776 13,965 26,026 39,991 Calico Agreement 2,958 2,400 600 3,000 Total $ 4,484 $ 27,603 $ 53,617 $ 81,220 Supplemental financial information related to the collaboration and license agreements are (in thousands): Years Ended December 31, 2021 2020 2019 Revenue recognized that was included in the contract liability at the beginning of the period $ 34,363 $ 17,570 $ 11,948 Revenue recognized from performance obligations fully or partially satisfied in previous periods 1,654 348 — As of December 31, 2021, the aggregate amount of the transaction price allocated to performance obligations under the Roche Agreement, the Biogen Agreement, and the Calico Agreement that are partially unsatisfied was $63.8 million.

Long-term Debt and Warrant - Re

Long-term Debt and Warrant - Related Party	12 Months Ended
	Dec. 31, 2021
Long Term Debt And Warrant Related Party [Abstract]
Long Term Debt and Warrant - Related Party	Note 9. Long-term debt and warrant – related party On June 5, 2020, contemporaneously with the completion of the Series B Financing, as described and defined in Note 10, Stockholders’ equity Credit Holdings III, LP, an affiliate of Perceptive Advisors LLC, or Perceptive, that provided for an aggregate principal borrowing amount of up to $20.0 million, available in two tranches of $12.5 million and $7.5 million. Perceptive is considered a related party to the Company based on its ownership of the Company’s common stock. In June 2020, the Company drew down on the first tranche of $12.5 million, or the Term Loan, which is outstanding as of December 31, 2021. The Company elected not to draw down the second tranche, which expired on June 30, 2021. The Term Loan is secured by a lien on substantially all of the Company’s assets and bears interest at a variable rate using the greater of LIBOR or 1.75%, plus 9.50%. The interest rate was 11.25% as of December 31, 2021. When the LIBOR interest rate is discontinued in the future, it is expected that the interest rate of the Term Loan would switch to Secured Overnight Financing Rate, or SOFR. As of December 31, 2021, the effect of switching from LIBOR to SOFR would not have been material to the Company’s consolidated financial statements. The Credit Agreement requires the Company to maintain a minimum aggregate cash balance of $3.0 million in one or more controlled accounts and contains various affirmative and negative covenants that limit its ability to engage in specified types of transactions. The Company is required to make interest-only payments until December 5, 2022, after which point the Company will be required to make payments of principal equal to 2% of the Term Loan until maturity on June 5, 2024, or the Maturity Date. If the Company pays off the Term Loan prior to the Maturity Date, it will be required to pay a prepayment fee. As of December 31, 2021, the prepayment fee would be $2.9 million. Under the terms of the Credit Agreement, Perceptive was issued a warrant to purchase up to 338,784 shares of the Company’s common stock at an exercise price of $8.86 per share. As further described in Note 10, Stockholders’ equity , in May 2021, Perceptive exercised its warrant using the net exercise method provided by the Credit Agreement. The following table contains the anticipated future minimum payments on long-term debt as of December 31, 2021 for each of the years ending December 31 and a reconciliation to the carrying value of long-term debt on the Company’s consolidated balance sheets (in thousands): Undiscounted, minimum long-term debt payments: 2022 $ — 2023 3,000 2024 9,500 Total minimum long-term debt payments 12,500 Less: Unamortized debt issuance costs and debt discount related to warrant (1,732 ) Total long-term debt—related party as of December 31, 2021 $ 10,768

Stockholders Equity

Stockholders Equity	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Stockholder's Equity	Note 10. Stockholders’ equity Common stock In October 2020, the Company authorized preferred stock issuable of 10,000,000 shares and increased its authorized common stock issuable to 150,000,000 shares, both with a $0.0001 par value per share. The holders of common stock are entitled to one vote for each share held at all meetings of stockholders and written actions in lieu of meetings provided. Subject to full payment of all preferential dividends to which the holders of preferred stock, if any, are entitled, the holders of common stock shall be entitled to receive dividends out of funds legally available. In the event of a liquidation, dissolution, or winding up of the Company, after payment or provision for payment of all debts and liabilities of the Company and all preferential amounts to which the holders of preferred stock, if any, are entitled with respect to the distribution of assets in liquidation, the holders of common stock shall be entitled to share ratably in the remaining assets of the Company available for distribution. The holders of common stock have no preemptive or other subscription rights, and there are no redemption or sinking fund provisions with respect to such stock. Reverse stock split As described in Note 1, Nature of the business and basis of presentation Public offerings of common stock On October 6, 2020, the Company completed its IPO at which time the Company issued 11,040,000 shares of its common stock at a price to the public of $19.00 per share, which number includes 1,440,000 shares of common stock that were issued to the underwriters for the IPO when they exercised in full their overallotment option. Upon the closing of the IPO, all outstanding shares of the Company’s redeemable convertible preferred stock automatically converted into 30,355,379 shares of common stock. In June 2021, the Company completed a follow-on public offering, at which time the Company issued 4,887,500 shares of its common stock, including 637,500 shares of common stock that were issued to the underwriters when they exercised in full their overallotment option. Net proceeds from the follow-on public offering, including the exercise in full of the underwriters’ option to purchase additional shares, were $169.5 million, after deducting underwriting discounts and commissions, and expenses. Perceptive warrant – related party As described in Note 9, Long-term debt and warrant – related party Preferred stock In June and July 2020, the Company closed a $150.0 million Series B Financing with existing and new investors. As part of the Series B Financing, the Company issued 142,857,142 shares of its Series B preferred stock at a purchase price of $1.05 per share, for aggregate gross proceeds of $150.0 million. Of the amounts above, 138,571,428 shares were issued for gross proceeds of $145.5 million, less related offering costs of $4.5 million in June 2020, and 4,285,714 shares were issued for proceeds of $4.5 million in July 2020. Upon the completion of the Company’s IPO on October 6, 2020, all outstanding shares of the Company’s preferred stock were converted into 30,355,379 shares of common stock with every 8.4335 shares of preferred stock converting into one share of common stock. As a result, as of December 31, 2021, and 2020, no shares of preferred stock were outstanding. At-The-Market Equity Program In November 2021, the Company filed an automatically effective registration statement on Form S-3, or the Registration Statement, with the SEC that registers the offering, issuance and sale of an unspecified amount of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. Simultaneously, the Company entered into an equity distribution agreement with Cowen and Company, LLC, as sales agent, to provide for the issuance and sale by the Company of up to $200.0 million of common stock from time to time in “at-the-market” offerings under the Registration Statement and related prospectus filed with the Registration Statement, or the ATM Program. As of December 31, 2021, no sales have been made under the ATM Program.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	Note 11. Stock-based compensation 2015 Incentive Stock Option and Grant Plan On December 28, 2015, the Company’s board of directors adopted the 2015 Incentive Stock Option and Grant Plan, or the 2015 Plan, and reserved 2,525,327 shares of common stock for issuance under this plan. The 2015 Plan authorized the board of directors or a committee of the board to grant incentive stock options, nonqualified stock options and restricted stock awards to eligible employees, outside directors and consultants of the Company. Options granted under the 2015 Plan generally vest over a period of five or eight years ten years 2020 Stock Option and Incentive Plan On September 8, 2020, the Company’s board of directors adopted the C4 Therapeutics, Inc. 2020 Stock Option and Incentive Plan, or the 2020 Plan, which became effective on September 30, 2020. Upon adoption there were 6,567,144 shares of common stock reserved for issuance under the 2020 Plan. The Company’s Board of Directors, the Compensation Committee of the Board of Directors, and, in certain contexts, the Chief Executive Officer of the Company are authorized to grant a broad range of stock-based awards under the 2020 Plan, including stock options, stock appreciation rights, or SARs, restricted stock awards, or RSAs, restricted stock units, or RSUs, performance awards and stock bonus awards to the Company’s officers, employees, directors and other key persons, including consultants. Following the effectiveness of the 2020 Plan, the Company ceased making grants under the 2015 Plan. However, the 2015 Plan continues to govern the terms and conditions of the outstanding awards granted under it. Shares of common stock subject to awards granted under the 2015 Plan that cease to be subject to such awards by forfeiture or otherwise after the termination of the 2015 Plan will be available for issuance under the 2020 Plan. As of December 31, 2021, the Company had an aggregate of 9,704,418 shares reserved under the 2020 Plan and 2015 Plan, of which 3,720,993 shares were available for future issuance under the 2020 Plan. The 2020 Plan provides for an annual increase, to be added on the first day of each fiscal year, beginning with January 1, 2021 and continuing until the expiration of the 2020 Plan, equal to the lesser of (i) 5% of the outstanding shares of common stock on the immediately preceding December 31st, or (ii) lesser number of shares determined by the administrator of the 2020 Plan, which is the Company’s Board of Directors or the Compensation Committee of the Board of Directors. On January 1, 2022, the annual increase for the 2020 Plan resulted in an additional 2,434,443 shares authorized for issuance being added to the 2020 Plan. President and Chief Executive Officer termination On March 3, 2020, or the Separation Date, the employment of the Company’s then current president and chief executive officer, or the Former CEO, terminated. The Company repurchased all of the Former CEO’s outstanding shares of common stock, which had been issued upon his exercise of previously granted stock options, for total consideration of $0.1 million. The Former CEO also relinquished his right to purchase shares of common stock upon the exercise of stock options that were vested as of his Separation Date, in exchange for total consideration paid by the Company of $0.7 million. The Company recognized the repurchase price of these shares of common stock and the relinquishment of these vested options in additional-paid-in-capital during the year ended December 31, 2020. Stock-based compensation expense was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Stock-based compensation expense: Research and development $ 7,526 $ 972 $ 395 General and administrative 13,986 2,460 1,247 Total stock-based compensation expense $ 21,512 $ 3,432 $ 1,642 The following table summarizes the stock option activity under the Company’s equity awards plans for the year ended December 31, 2021 : Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2020 5,029,364 $ 12.72 9.25 $ 102,635 Granted 1,926,579 41.71 Exercised (474,850 ) 4.91 Forfeited/expired (497,668 ) 16.91 Outstanding as of December 31, 2021 5,983,425 $ 22.33 8.64 $ 75,538 Exercisable as of December 31, 2021 1,362,477 $ 16.86 8.10 $ 22,699 Vested and expected to vest as of December 31, 2021 5,983,425 $ 22.33 8.64 $ 75,538 Other information related to the option activity of the Company was as follows: Years Ended December 31, 2021 2020 2019 Weighted-average fair value of options granted $ 29.54 $ 9.24 $ 4.13 Intrinsic value of options exercised (in thousands) $ 17,321 $ 2,587 $ 337 As of December 31, 2021, the unrecognized compensation cost related to outstanding options was $74.5 million, which is expected to be recognized over a weighted-average period of 2.9 years. The following table summarizes assumptions used in the Black-Scholes option pricing model to determine the fair value of stock options granted to employees: Years Ended December 31, 2021 2020 2019 Expected option life (years) 5.50 - 6.11 5.23 - 6.35 6.35 Risk-free interest rate 0.59% - 1.34% 0.32% - 0.57% 1.71% - 2.36% Expected volatility 80.45% - 86.20% 69.54% - 83.76% 65.50% - 76.80% Expected dividend yield 0.00% 0.00% 0.00% 2020 Employee Stock Purchase Plan In September 2020, the Company’s Board of Directors adopted the C4 Therapeutics, Inc. 2020 Employee Stock Purchase Plan, or the 2020 ESPP. Eligible employees may authorize payroll deductions of up to 15% of their eligible compensation during an offering period. The Company may hold one or more offering periods each year during which employees will be able to purchase shares under the 2020 ESPP. The Company held its first two six-month offering periods during the year ended December 31, 2021 and issued 6,640 shares. As of December 31, 2021, the Company had 861,765 shares available for future issuance under the 2020 ESPP. The 2020 ESPP provides for an annual increase to be added on the first day of each fiscal year, beginning with January 1, 2021 and continuing thereafter through January 1, 2030, equal to the lesser of (i) 1% of the outstanding shares of common stock on the immediately preceding December 31st, (ii) 656,714 shares, or (ii) lesser number of shares determined by the administrator of the 2020 ESPP. On January 1, 2022, the annual increase for the 2020 ESPP resulted in an additional 486,888 shares authorized for issuance being added to the 2020 ESPP. Restricted stock units In January and February 2022, the Company’s Board of Directors authorized an issuance of 563,500 RSUs to certain employees, including members of the Company’s leadership team under the 2020 Plan. Vesting of the RSUs are contingent upon the determination of achievement of certain discovery and clinical milestones, or as specified market conditions are met. Upon vesting, each RSU converts automatically into one share of the Company’s common stock.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 12. Income Taxes Income tax (benefit) expense consists of the following (in thousands): Years Ended December 31, 2021 2020 2019 Current tax provision: Current federal provision $ — $ (673 ) $ 669 Current state provision — 47 135 Total current provision — (626 ) 804 Deferred tax provision: Deferred federal provision — — — Deferred state provision — — — Total tax provision $ — $ (626 ) $ 804 Tax rate reconciliation A reconciliation of the expected income tax (benefit) expense computed at the statutory federal rate to income taxes as reflected in the consolidated financial statements was as follows: Years Ended December 31, 2021 2020 2019 Income tax benefit computed at federal statutory tax rate 21.0 % 21.0 % 21.0 % Stock-based compensation (1.3 )% (0.1 )% (0.4 )% State tax—net of federal 6.0 % 11.2 % 6.5 % State credits 1.7 % 1.2 % 0.6 % Federal credits 3.1 % 3.5 % 1.1 % Valuation allowance (30.2 )% (34.1 )% (32.1 )% Net operating loss carryback benefits — 1.0 % — Tax attributes true up due to net operating loss carryback — (1.0 )% — Other permanent differences (0.3 )% (1.8 )% 0.9 % Total 0.0 % 0.9 % (2.4 )% Significant components of deferred taxes Deferred income taxes reflect the net tax effects of (a) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes and (b) operating losses and tax credit carryforwards. Significant components of the Company’s deferred tax assets and deferred tax liabilities were as follows (in thousands): As of December 31, 2021 2020 Deferred tax assets: Capitalized start-up costs $ 875 $ 1,075 Operating lease liability 9,290 3,859 Stock-based compensation 3,675 1,344 Net operating losses 46,339 19,399 R&D and investment tax credits 9,560 5,578 Unrealized gain/loss 195 — Deferred revenue 15,053 23,157 Other 426 168 Total gross deferred tax assets 85,413 54,580 Deferred tax liabilities: Right-of-use asset (9,242 ) (3,967 ) Fixed assets (725 ) (744 ) Unrealized gain/loss — (3 ) Less: valuation allowance (75,446 ) (49,866 ) Net deferred taxes $ — $ — The Company has evaluated the positive and negative evidence bearing upon the realizability of the deferred tax assets. As of December 31, 2021 and 2020, based on the Company’s historical operating losses, the Company has concluded that it is more-likely-than-not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company has provided a full valuation allowance for the deferred tax assets as of December 31, 2021 and 2020. The valuation allowance for deferred tax assets as of December 31, 2021 and 2020 was $75.4 million and $49.9 million, respectively. The net valuation allowance increase of $25.6 million during the year ended December 31, 2021 was primarily due to the increase in net operating loss and tax credits carryforward and a decrease in deferred revenue recognized during the year. As of December 31, 2021 and 2020, the Company had $152.2 million and $59.7 million gross United States federal net operating loss, or NOL, carryforwards, respectively, which may be available to offset future income tax liabilities. The Tax Cuts and Jobs Act, or TCJA, which was enacted in December 2017, will generally allow federal losses generated after 2017 to be carried over indefinitely, but will generally limit the NOL deduction to the lesser of the NOL carryover or 80% of a corporation’s taxable income (subject to Section 382 of the Internal Revenue Code of 1986, as amended, or IRC). In addition, there will be no carryback for losses generated after 2017. Losses generated prior to 2018 will generally be deductible to the extent of the lesser of a corporation’s NOL carryover or 100% of a corporation’s taxable income and be available for twenty years from the period the loss was generated. For U.S. federal income tax purposes, the Company has federal NOLs generated after 2017 of $ As of December 31, 2021 and 2020, the Company has total gross United States state net operating loss carryforwards of $216.8 million and $106.3 million, respectively, which may be available to offset future income tax liabilities that expire at various dates through 2041. At December 31, 2021 and 2020, the Company has United States federal research credit carryforwards of $7.3 million and $4.7 million, respectively, which are available to offset future federal income tax liabilities, which expire at various dates through 2041. At December 31, 2021 and 2020, the Company has United States state research credit carryforwards of $2.9 million and $1.1 million, respectively, which are available to reduce future tax liabilities which expire at various dates through 2036. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50%, as defined under Sections 382 and 383 of the IRC, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. In 2020, the Company completed a study of ownership changes from inception through December 31, 2020, to assess whether an ownership change has occurred or whether there have been multiple ownership changes since its formation. The result of this study indicated that the Company experienced ownership changes as defined by IRS Section 382 of the Code, however there are no net operating loss carryforwards that will be limited and expire unused as a result of such ownership changes. A full valuation allowance has been provided against the Company’s net operating loss and tax credit carryforwards and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. The Company will recognize interest and/or penalties related to uncertain tax benefits in income tax expense as they arise. As of December 31, 2021 and 2020 , the Company had no accrued interest or penalties related to uncertain tax benefits. The Company files income tax returns in the United States, California, Florida, and Massachusetts. The federal and state income tax returns are generally subject to tax examinations for the tax years ended December 31, 2018 through present. To the extent that the Company has tax attribute carryforwards, the tax years in which the attributes were generated may still be adjusted upon examination by the Internal Revenue Services or State tax authorities to the extent utilized in a future period. The Company is not currently under examination by any tax authorities.

Loss Per Share

Loss Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Loss Per Share	Note 13. Loss per share As described in Note 2, Summary of significant accounting policies Years Ended December 31, 2021 2020 2019 Series Seed Preferred Stock — — 474,298 Series A Preferred Stock — — 12,941,857 Options to purchase common stock 5,983,425 5,029,364 2,310,886 Warrant to purchase common stock — 338,784 — 5,983,425 5,368,148 15,727,041 All redeemable, convertible preferred stock, including those that were outstanding as of December 31, 2019, as shown above, were converted to shares of the Company’s common stock and effected for a one-for-8.4335 Long-term debt and warrant – related party , in May 2021, Perceptive exercised its warrant using the net exercise method provided by the Credit Agreement. Basic and diluted loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding (in thousands, except share and per share data): Years Ended December 31, 2021 2020 2019 Numerator: Net loss $ (83,892 ) $ (66,335 ) $ (34,099 ) Accrual of preferred stock dividends — — (8,468 ) Net loss attributable to common stockholders—basic and diluted $ (83,892 ) $ (66,335 ) $ (42,567 ) Denominator: Weighted-average common stock outstanding—basic and diluted 46,041,733 11,370,328 1,371,905 Net loss per share attributable to common stockholders—basic and diluted $ (1.82 ) $ (5.83 ) $ (31.03 )

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Defined Contribution Plan	Note 14. Defined contribution plan The Company has a 401(k) retirement plan, the 401(k) Plan, whereby all full-time employees may contribute up to 90% of their pre-tax compensation, up to the maximum allowable amount set by the Internal Revenue Service. The Company, at its discretion, matches 100% of contributions to the 401(k) Plan up to a maximum of $6,000 per year for each full-time employee. During each of the years ended December 31, 2021, 2020, and 2019 the Company contributed approximately $0.6 million, $0.5 million, and $0.4 million, respectively, to the 401(k) Plan.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The Company has prepared the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States of America, or U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.
Principles of consolidation	Principles of consolidation The Company’s consolidated financial statements include the accounts of C4 Therapeutics, Inc. and its wholly owned subsidiary C4T Securities Corporation, a Massachusetts securities corporation. All significant intercompany balances and transactions have been eliminated in consolidation.
Use of estimates	Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. This process may result in actual results differing materially from those estimated amounts used in the preparation of the consolidated financial statements if these results differ from historical experience or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, amounts and timing of revenues recognized under the Company’s research and development collaboration arrangements, prepaid and accrued research and development expense, incremental borrowing rate used in the measurement of lease liability, and estimated volatility used in fair valuation of stock options. The Company assesses estimates on an ongoing basis; however, actual results could materially differ from those estimates.
Segments	Segments Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purpose of allocating resources. All of the Company’s long-lived assets are held in the United States.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. The Company’s cash equivalents are measured at fair value on a recurring basis.
Marketable securities	Marketable securities The Company classifies marketable securities with a remaining maturity when purchased of greater than three months as available-for-sale. Marketable securities with a remaining maturity date greater than one year are classified as non-current assets.
Restricted cash	Restricted cash Restricted cash consists of cash placed in separate restricted bank account as required under the terms of the Company’s lease agreements for its Watertown, Massachusetts facility, as further described within Note 6, Leases
Concentrations of credit risk	Concentrations of credit risk Financial instruments that potentially subject the Company to significant concentration of credit risk consist primarily of cash, cash equivalents, marketable securities, and restricted cash. The Company may maintain deposits in financial institutions in excess of government insured limits. The Company believes that it is not exposed to significant credit risk as its deposits are held at financial institutions that management believes to be of high credit quality and the Company has not experienced any losses on these deposits. Additionally, t he Company has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The Company maintains its funds in accordance with its investment policy, which defines allowable investments, specifies credit quality standards and is designed to limit credit exposure to any single issuer.
Fair value of financial instruments	Fair value of financial instruments ASC Topic 820, Fair Value Measurement • Level 1—Quoted market prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. • Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company evaluates transfers between levels at the end of each reporting period.
Property and equipment	Property and equipment Property and equipment are recorded at cost. Expenditures for repairs and maintenance are expensed as incurred. When assets are retired or disposed of, the assets and related accumulated depreciation are derecognized from the accounts, and any resulting gain or loss is included in the determination of net loss. Depreciation on equipment is calculated using the straight-line method over the estimated useful lives of the assets as follows: Asset category Estimated useful life Laboratory equipment 5 years Computer equipment 3 years Office equipment, furniture and fixtures 5 years Leasehold improvements Lesser of useful life or remaining lease term
Leases	Leases The Company accounts for leases in accordance with ASC Topic 842, Leases Certain adjustments to the right-of-use asset may be required for items such as incentives received. The Company typically only includes an initial lease term in its assessment of a lease arrangement; options to renew a lease are not included in the assessment unless there is reasonable certainty that the Company will renew.
Impairment of long-lived assets	Impairment of long-lived assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceed the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.
Commitments and contingencies	Commitments and contingencies Liabilities for loss contingencies arising from claims, assessments, litigation, fines and penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred.
Revenue recognition	Revenue recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers The Company enters into collaboration and licensing agreements with strategic partners, which are within the scope of ASC 606, under which it may exclusively license rights to research, develop, manufacture, and commercialize its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: (1) non-refundable, upfront license fees; (2) reimbursement of certain costs; (3) customer option fees for additional goods or services; (4) development milestone payments, (5) regulatory and commercial milestone payments; and (6) royalties on net sales of licensed products. In determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of its agreements, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use its 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; (c) the stand-alone selling price for each performance obligation identified in the contract for the allocation of transaction price in step (iv) above; and (d) the contract term and pattern of satisfaction of the performance obligations under step (v) above. The Company uses judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. Amounts due to the Company for satisfying the revenue recognition criteria or that are contractually due based upon the terms of the collaboration agreements are recorded as accounts receivable in the Company’s consolidated balance sheet. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Upfront license fees If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, manufacturing, and commercialization capabilities of the customer; the retention of any key rights by the Company; and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promises, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise and whether it is separately identifiable from the remaining promise. For licenses that are combined with other promises, the Company exercises judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights or options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised. If an option is not exercised and the target is terminated, the Company will accelerate and recognize all remaining revenue related to the material right performance obligation. Research and development services The promises under the Company’s collaboration agreements may include research and development services to be performed by the Company for or on behalf of the customer. Payments or reimbursements resulting from the Company’s research and development efforts are recognized as the services are performed and presented on a gross basis because the Company is the principal for such efforts. Reimbursements from and payments to the customer that are the result of a collaborative relationship with the customer, instead of a customer relationship, such as co-development activities, are recorded as a reduction to research and development expense. Milestone payments At the inception of each arrangement that includes development milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company evaluates factors such as the scientific, clinical, regulatory, commercial and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant revenue reversal would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. For further discussion of accounting for collaboration revenues, see Note 8, License Agreements.
Research and development	Research and development Research and development costs are expensed as incurred. Research and development costs include salaries, stock-based compensation and other employee benefit expenses, lab related supplies 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 research and development activities. Costs associated with licenses of technology are expensed as incurred and are included in research and development expense in the consolidated statement of operations and comprehensive loss. As part of the process of preparing the consolidated financial statements, the Company is required to estimate their accrued research and development expenses. The Company makes estimates of the accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known at that time. In addition, there may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense in which case such amounts are reflected as prepaid expenses and other current assets. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual or the amount of prepaid expenses accordingly. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized in prepaid expenses and other current assets. The capitalized amounts are expensed as the related goods are delivered or the services are performed.
Stock-based compensation	Stock-based compensation The Company measures and recognizes stock-based compensation expense based on the grant date fair value of equity awards measured using the Black-Scholes option pricing model. The Black-Scholes option pricing model estimates the fair value of the equity award using the expected term, expected volatility, risk-free interest rate, dividend rate, and the fair value of the common stock underlying the stock-based award. The Company estimates the expected life stock options using the “simplified” method, whereby, the expected life equals the arithmetic average of the vesting term and the original contractual term of the option. Due to the lack of sufficient company-specific historical and implied volatility data, the Company has based its computation of expected volatility on the historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The risk-free interest rates for periods within the expected life of the option were based on the U.S. Treasury yield curve in effect during the period the options were granted. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock. The Company recognizes forfeitures as they occur. Prior to the IPO, the fair value of common stock underlying stock-based awards was based on an estimate at each grant date by the Company’s board of directors. The Company determined the estimated per share fair value of its common stock at various dates considering contemporaneous and retrospective valuations in accordance with the guidance outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation Subsequent to the IPO, the fair value of the common stock underlying shared based awards is the quoted market price of the Company’s common stock on the date of the grant. The Company recognizes stock-based compensation expense on a straight-line basis over the requisite service period of the awards for service-based awards, which is generally the vesting period. Stock-based compensation expense is classified in the consolidated statement of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified.
Warrant liability expense	Warrant liability expense In June 2020, the Company issued a warrant to purchase shares of its Series B redeemable convertible preferred stock. Upon issuance, the Company classified the warrant as a liability on its consolidated balance sheet and remeasured the fair value of the warrant liability at each reporting date using the Black-Scholes option pricing model. The Black-Scholes option pricing model incorporates assumptions and estimates to value the warrant. Estimates and assumptions impacting the fair value measurement include the fair value per share of the underlying redeemable convertible Series B Preferred Stock or common stock issuable upon exercise of the warrant, remaining contractual term of the warrant, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying redeemable convertible preferred stock or common stock. Changes in the fair value of the warrant liability at each reporting period was recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Upon completion of the IPO, the warrant converted into a warrant to purchase shares of the Company’s common stock, as described in Note 9, Long-term debt and warrant liability
Income taxes	Income taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequence of events that have been recognized in the consolidated financial statements or the Company’s tax returns. Under this method, deferred tax assets and liabilities are determined based on the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established. The Company accounts for uncertain tax positions recognized in the consolidated financial statements by prescribing a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, which are considered appropriate as well as the related net interest and penalties.
Comprehensive loss	Comprehensive loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) which includes certain changes in equity that are excluded from net loss. The Company’s only element of other comprehensive income is unrealized gains and losses on marketable securities.
Net loss per share	Net loss per share Basic net loss per share and diluted net loss per share are computed using the weighted-average number of shares of common stock outstanding for the period. Net loss per share attributable to common stockholders is calculated using the two-class method, which is an earnings allocation formula that determines net loss per share for the holders of shares of the Company’s common stock and participating securities. The Company’s preferred stock contained participation rights in any dividend paid by the Company and was deemed to be a participating security. The participating securities do not include a contractual obligation to share in losses of the Company and are not included in the calculation of net loss per share in the periods in which a net loss is recorded. Diluted net loss per share is computed using the more dilutive of (a) the two-class method or (b) the if-converted method. The Company allocated earnings first to preferred stockholders based on dividend rights and then to common and preferred stockholders based on ownership interests. The weighted-average number of shares of common stock included in the computation of diluted net loss gives effect to all potentially dilutive common stock equivalent shares, including outstanding stock options and Preferred Stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Going concern	Going concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash, cash equivalent, and marketable securities balances.
Recently adopted accounting standards	Recently adopted accounting standards In December 2019, the FASB issued Accounting Standards Update, or ASU, No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, or Recently issued accounting standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Depreciation on Equipment Calculated Using Straight-Line Method Over Estimated Useful Lives of Assets	Depreciation on equipment is calculated using the straight-line method over the estimated useful lives of the assets as follows: Asset category Estimated useful life Laboratory equipment 5 years Computer equipment 3 years Office equipment, furniture and fixtures 5 years Leasehold improvements Lesser of useful life or remaining lease term

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicates the level of the fair value hierarchy utilized to determine such fair values as of December 31, 2021 (in thousands): Fair Value Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 59,162 $ 59,162 $ — $ — Corporate debt securities 11,649 — 11,649 — U.S. Treasury securities 5,000 — 5,000 — Marketable securities: Corporate debt securities 308,300 — 308,300 — U.S. government debt securities 37,883 — 37,883 — U.S. Treasury securities 29,172 — 29,172 — Total cash equivalents and marketable securities $ 451,166 $ 59,162 $ 392,004 $ — The following table sets forth the fair value of the Company’s financial assets by level within the fair value hierarchy at December 31, 2020 (in thousands): Fair Value Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 180,078 $ 180,078 $ — $ — Marketable securities: U.S. Treasury securities 189,962 — 189,962 — Total cash equivalents and marketable securities $ 370,040 $ 180,078 $ 189,962 $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2021
Marketable Securities [Abstract]
Summary of Marketable Securities	Marketable securities at December 31, 2021 consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities: Corporate debt securities $ 308,952 $ 1 $ (653 ) $ 308,300 U.S. government debt securities 37,988 — (105 ) 37,883 U.S. Treasury securities 29,190 — (18 ) 29,172 Total marketable securities, current and non-current $ 376,130 $ 1 $ (776 ) $ 375,355 Marketable securities at December 31, 2020 consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Loss Fair Value Marketable securities U.S. Treasury securities $ 189,949 $ 13 $ — $ 189,962 Total marketable securities, current $ 189,949 $ 13 $ — $ 189,962

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following (in thousands): As of December 31, 2021 2020 Property and equipment Laboratory equipment $ 8,276 $ 7,207 Furniture and fixtures 805 805 Leasehold improvements 541 541 Computer equipment 223 223 Office equipment 179 179 Total property and equipment 10,024 8,955 Less: accumulated depreciation (6,916 ) (5,632 ) Total property and equipment, net $ 3,108 $ 3,323
Summary of Depreciation Expense Related to Property and Equipment	Depreciation expense related to property and equipment was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Depreciation expense $ 1,492 $ 1,617 $ 1,595

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Lessee Lease Description [Line Items]
Summary of Lease Term and Incremental Borrowing Rate Applied in Arriving at Lease Liability	The following table summarizes the lease term and incremental borrowing rate applied in arriving at the lease liability: As of December 31, 2021 2020 Remaining lease term 10.2 years 7.3 years Incremental borrowing rate 5.2 % 10.0 %
Undiscounted Minimum Future Lease Payments Under Non-cancelable Leases	Future lease payments under non-cancelable leases as of December 31, 2021 for each of the years ending December 31 are as follows (in thousands): Undiscounted lease payments*: 2022 $ 2,994 2023 3,491 2024 3,596 2025 3,704 2026 3,815 Thereafter 25,085 Total undiscounted lease payments 42,685 Less: imputed interest (10,574 ) Total operating lease liability as of December 31, 2021 $ 32,111 *As stated above, this table does not include lease payments for the Newly Leased Space under the Amended Lease as the commencement date is subsequent to December 31, 2021.
Watertown Lease
Lessee Lease Description [Line Items]
Summary of Lease Costs	The elements of lease costs were as follows (in thousands): Years Ended December 31, 2021 2020 2019 Lease cost: Operating lease cost $ 2,686 $ 2,550 $ 2,550 Variable lease cost 857 1,066 1,020 Total lease cost $ 3,543 $ 3,616 $ 3,570

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Payables And Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): As of December 31, 2021 2020 Accrued expenses and other current liabilities: Accrued research and development $ 6,863 $ 3,799 Accrued compensation and benefits 5,084 3,724 Accrued professional fees 1,246 1,532 Other 413 469 Total accrued expenses and other current liabilities $ 13,606 $ 9,524

Collaboration and License Agr_2

Collaboration and License Agreements (Tables)	12 Months Ended
	Dec. 31, 2021
Collaboration And License Agreements [Abstract]
Summary of Allocation of Total Transaction Price and Unsatisfied Transaction Price	The following table summarizes the allocation of the total transaction price to the identified performance obligations under the arrangement, and the amount of the transaction price unsatisfied as of December 31, 2021 (in thousands): Transaction Price Allocated Transaction Price Unsatisfied Performance obligations: Research and development targets $ 58,628 $ 26,996 Option rights 6,694 3,488 Total $ 65,322 $ 30,484
Schedule of Revenue from Collaboration Agreements	Revenue from collaboration agreements was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Revenue from collaboration agreements: Roche Agreement $ 19,379 $ 9,051 $ 6,409 Biogen Agreement 15,720 9,913 2,432 Calico Agreement 10,686 14,231 12,540 Total revenue from collaboration agreements $ 45,785 $ 33,195 $ 21,381
Schedule of Financial Information Related to Collaboration and License Agreements	Supplemental information related to the collaboration and license agreements consisted of the following in the Company’s consolidated balance sheet as of December 31, 2021 (in thousands): Accounts Receivable Deferred Revenue, Current Deferred Revenue, Net of Current Deferred Revenue, Total Supplemental information: Roche Agreement $ 1,215 $ 5,601 $ 17,215 $ 22,816 Biogen Agreement 3,000 24,032 6,611 30,643 Calico Agreement 1,501 2,167 542 2,709 Total $ 5,716 $ 31,800 $ 24,368 $ 56,168 Supplemental information related to the collaboration and license agreements consisted of the following in the Company’s consolidated balance sheet as of December 31, 2020 (in thousands): Accounts Receivable Deferred Revenue, Current Deferred Revenue, Net of Current Deferred Revenue, Total Supplemental information: Roche Agreement 750 11,238 26,991 38,229 Biogen Agreement 776 13,965 26,026 39,991 Calico Agreement 2,958 2,400 600 3,000 Total $ 4,484 $ 27,603 $ 53,617 $ 81,220
Schedule of Supplemental Financial Information Related to Collaboration and License Agreements	Supplemental financial information related to the collaboration and license agreements are (in thousands): Years Ended December 31, 2021 2020 2019 Revenue recognized that was included in the contract liability at the beginning of the period $ 34,363 $ 17,570 $ 11,948 Revenue recognized from performance obligations fully or partially satisfied in previous periods 1,654 348 —

Long Term Debt and Warrant - Re

Long Term Debt and Warrant - Related Party (Tables)	12 Months Ended
	Dec. 31, 2021
Long Term Debt And Warrant Related Party [Abstract]
Summary of Anticipated Future Minimum Payments of Long-term Debt	The following table contains the anticipated future minimum payments on long-term debt as of December 31, 2021 for each of the years ending December 31 and a reconciliation to the carrying value of long-term debt on the Company’s consolidated balance sheets (in thousands): Undiscounted, minimum long-term debt payments: 2022 $ — 2023 3,000 2024 9,500 Total minimum long-term debt payments 12,500 Less: Unamortized debt issuance costs and debt discount related to warrant (1,732 ) Total long-term debt—related party as of December 31, 2021 $ 10,768

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock-based Compensation Expense	Stock-based compensation expense was as follows (in thousands): Years Ended December 31, 2021 2020 2019 Stock-based compensation expense: Research and development $ 7,526 $ 972 $ 395 General and administrative 13,986 2,460 1,247 Total stock-based compensation expense $ 21,512 $ 3,432 $ 1,642
Summary of Stock Option Activity	The following table summarizes the stock option activity under the Company’s equity awards plans for the year ended December 31, 2021 : Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2020 5,029,364 $ 12.72 9.25 $ 102,635 Granted 1,926,579 41.71 Exercised (474,850 ) 4.91 Forfeited/expired (497,668 ) 16.91 Outstanding as of December 31, 2021 5,983,425 $ 22.33 8.64 $ 75,538 Exercisable as of December 31, 2021 1,362,477 $ 16.86 8.10 $ 22,699 Vested and expected to vest as of December 31, 2021 5,983,425 $ 22.33 8.64 $ 75,538 Other information related to the option activity of the Company was as follows: Years Ended December 31, 2021 2020 2019 Weighted-average fair value of options granted $ 29.54 $ 9.24 $ 4.13 Intrinsic value of options exercised (in thousands) $ 17,321 $ 2,587 $ 337
Summary of Significant Assumptions Used in the Black-scholes Pricing Model to Determine the Fair Value of Stock Options Granted	The following table summarizes assumptions used in the Black-Scholes option pricing model to determine the fair value of stock options granted to employees: Years Ended December 31, 2021 2020 2019 Expected option life (years) 5.50 - 6.11 5.23 - 6.35 6.35 Risk-free interest rate 0.59% - 1.34% 0.32% - 0.57% 1.71% - 2.36% Expected volatility 80.45% - 86.20% 69.54% - 83.76% 65.50% - 76.80% Expected dividend yield 0.00% 0.00% 0.00%

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Summary of Income Tax (Benefit) Expense	Income tax (benefit) expense consists of the following (in thousands): Years Ended December 31, 2021 2020 2019 Current tax provision: Current federal provision $ — $ (673 ) $ 669 Current state provision — 47 135 Total current provision — (626 ) 804 Deferred tax provision: Deferred federal provision — — — Deferred state provision — — — Total tax provision $ — $ (626 ) $ 804
Summary of Reconciliation of Expected Income Tax (Benefit) Expense	A reconciliation of the expected income tax (benefit) expense computed at the statutory federal rate to income taxes as reflected in the consolidated financial statements was as follows: Years Ended December 31, 2021 2020 2019 Income tax benefit computed at federal statutory tax rate 21.0 % 21.0 % 21.0 % Stock-based compensation (1.3 )% (0.1 )% (0.4 )% State tax—net of federal 6.0 % 11.2 % 6.5 % State credits 1.7 % 1.2 % 0.6 % Federal credits 3.1 % 3.5 % 1.1 % Valuation allowance (30.2 )% (34.1 )% (32.1 )% Net operating loss carryback benefits — 1.0 % — Tax attributes true up due to net operating loss carryback — (1.0 )% — Other permanent differences (0.3 )% (1.8 )% 0.9 % Total 0.0 % 0.9 % (2.4 )%
Summary of Significant Components of Deferred Tax Assets and Deferred Tax Liabilities	Deferred income taxes reflect the net tax effects of (a) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes and (b) operating losses and tax credit carryforwards. Significant components of the Company’s deferred tax assets and deferred tax liabilities were as follows (in thousands): As of December 31, 2021 2020 Deferred tax assets: Capitalized start-up costs $ 875 $ 1,075 Operating lease liability 9,290 3,859 Stock-based compensation 3,675 1,344 Net operating losses 46,339 19,399 R&D and investment tax credits 9,560 5,578 Unrealized gain/loss 195 — Deferred revenue 15,053 23,157 Other 426 168 Total gross deferred tax assets 85,413 54,580 Deferred tax liabilities: Right-of-use asset (9,242 ) (3,967 ) Fixed assets (725 ) (744 ) Unrealized gain/loss — (3 ) Less: valuation allowance (75,446 ) (49,866 ) Net deferred taxes $ — $ —

Loss Per Share (Tables)

Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders	Years Ended December 31, 2021 2020 2019 Series Seed Preferred Stock — — 474,298 Series A Preferred Stock — — 12,941,857 Options to purchase common stock 5,983,425 5,029,364 2,310,886 Warrant to purchase common stock — 338,784 — 5,983,425 5,368,148 15,727,041
Schedule of Basic and Diluted Loss Per Share	All redeemable, convertible preferred stock, including those that were outstanding as of December 31, 2019, as shown above, were converted to shares of the Company’s common stock and effected for a one-for-8.4335 Long-term debt and warrant – related party , in May 2021, Perceptive exercised its warrant using the net exercise method provided by the Credit Agreement. Basic and diluted loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding (in thousands, except share and per share data): Years Ended December 31, 2021 2020 2019 Numerator: Net loss $ (83,892 ) $ (66,335 ) $ (34,099 ) Accrual of preferred stock dividends — — (8,468 ) Net loss attributable to common stockholders—basic and diluted $ (83,892 ) $ (66,335 ) $ (42,567 ) Denominator: Weighted-average common stock outstanding—basic and diluted 46,041,733 11,370,328 1,371,905 Net loss per share attributable to common stockholders—basic and diluted $ (1.82 ) $ (5.83 ) $ (31.03 )

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Details) $ in Thousands	Oct. 06, 2020USD ($)shares	Sep. 25, 2020	Jun. 30, 2021USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Class Of Stock [Line Items]
Net loss				$ 83,892	$ 66,335	$ 34,099
Accumulated deficit				267,715	$ 183,823
Net proceeds from issuance of follow-on after deducting expenses and underwriting discounts and commissions			$ 169,500
Cash, cash equivalents and marketable securities				$ 451,500
Reverse stock split		one-for-8.4335		one-for-8.4335
Stock split conversion ratio		0.118574732		0.118574732
IPO
Class Of Stock [Line Items]
Initial public offering closing date	Oct. 6, 2020
Outstanding shares of preferred stock automatically converted | shares	30,355,379
Common Stock | IPO
Class Of Stock [Line Items]
Initial public offering closing date	Oct. 6, 2020
Outstanding shares of preferred stock automatically converted | shares	30,355,379
Net proceeds after deducting expenses and underwriting discounts and commissions	$ 191,200

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021USD ($)SEGMENT
Accounting Policies [Abstract]
Number of operating segments | SEGMENT	1
Expected dividend yield | $	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Depreciation on Equipment Calculated Using Straight-Line Method Over Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2021
Laboratory Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Office Equipment Furniture And Fixtures
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	Lesser of useful life or remaining lease term

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Marketable securities:
Total cash equivalents and marketable securities	$ 451,166	$ 370,040
Money Market Funds
Cash equivalents:
Cash equivalents	59,162	180,078
Corporate Debt Securities
Cash equivalents:
Cash equivalents	11,649
Marketable securities:
Marketable securities	308,300
U.S. Treasury Securities
Cash equivalents:
Cash equivalents	5,000
Marketable securities:
Marketable securities	29,172	189,962
U.S. Government Debt Securities
Marketable securities:
Marketable securities	37,883
Level 1
Marketable securities:
Total cash equivalents and marketable securities	59,162	180,078
Level 1 | Money Market Funds
Cash equivalents:
Cash equivalents	59,162	180,078
Level 2
Marketable securities:
Total cash equivalents and marketable securities	392,004	189,962
Level 2 | Corporate Debt Securities
Cash equivalents:
Cash equivalents	11,649
Marketable securities:
Marketable securities	308,300
Level 2 | U.S. Treasury Securities
Cash equivalents:
Cash equivalents	5,000
Marketable securities:
Marketable securities	29,172	$ 189,962
Level 2 | U.S. Government Debt Securities
Marketable securities:
Marketable securities	$ 37,883

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 376,130	$ 189,949
Gross Unrealized Gains	1	13
Gross Unrealized Loss	(776)
Fair Value	375,355	189,962
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	308,952
Gross Unrealized Gains	1
Gross Unrealized Loss	(653)
Fair Value	308,300
U.S. Government Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	37,988
Gross Unrealized Loss	(105)
Fair Value	37,883
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	29,190	189,949
Gross Unrealized Gains		13
Gross Unrealized Loss	(18)
Fair Value	$ 29,172	$ 189,962

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)MarketableSecurity
Marketable Securities [Abstract]
Number of marketable securities | MarketableSecurity	123
Marketable securities	$ 365,500
Individual securities	0
Other-than-temporary impairment losses	$ 0

Property and Equipment - Summar

Property and Equipment - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment	$ 10,024	$ 8,955
Less: accumulated depreciation	(6,916)	(5,632)
Total property and equipment, net	3,108	3,323
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment	8,276	7,207
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment	805	805
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	541	541
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment	223	223
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment	$ 179	$ 179

Property and Equipment - Summ_2

Property and Equipment - Summary of Depreciation Expense Related to Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Depreciation expense	$ 1,492	$ 1,617	$ 1,595

Leases - Additional Information

Leases - Additional Information (Details)	1 Months Ended		12 Months Ended
	Nov. 30, 2021USD ($)Contract	Jul. 31, 2017	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Lessee Lease Description [Line Items]
Right-of-use assets			$ 31,945,000	$ 13,229,000
Liabilities under lease			32,111,000
Watertown Lease
Lessee Lease Description [Line Items]
Right-of-use assets			16,700,000
Liabilities under lease			15,100,000
Construction costs			1,500,000
Tenant improvements	$ 2,600,000		$ 0
Watertown Lease | Office and Laboratory Space
Lessee Lease Description [Line Items]
Lease commencement date		2018-04
Lessee operating lease, description			In July 2017, the Company entered into a lease of office and laboratory space for its headquarters in Watertown, Massachusetts, or the Watertown Lease. The Watertown Lease had a non-cancelable term of ten years with an option to extend for one additional five-year period and is subject to rent escalation throughout the term. Additionally, the Watertown Lease required the Company to provide collateral, which was recorded as restricted cash on the consolidated balance sheets. The Watertown Lease commenced in April 2018.
Watertown Lease | Newly Leased Space
Lessee Lease Description [Line Items]
Right-of-use assets	20,100,000
Liabilities under lease	$ 20,100,000
Amended lease commencement date	2022-01
Rent commencing after lease commencement period	2 months
Amended lease termination date	2032-01
Lease term of amended lease terminate period	10 years
Tenant improvements	$ 2,600,000
Extend lease term of amended lease period	5 years
Restricted cash	$ 3,300,000
Number of amended lease separate contracts | Contract	2
Undiscounted lease payments	$ 62,100,000

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs (Details) - Watertown Lease - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease cost:
Operating lease cost	$ 2,686	$ 2,550	$ 2,550
Variable lease cost	857	1,066	1,020
Total lease cost	$ 3,543	$ 3,616	$ 3,570

Leases - Summary of Lease Term

Leases - Summary of Lease Term and Incremental Borrowing Rate Applied In Arriving at Lease Liability (Details)	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Remaining lease term	10 years 2 months 12 days	7 years 3 months 18 days
Incremental borrowing rate	5.20%	10.00%

Leases - Undiscounted Minimum F

Leases - Undiscounted Minimum Future Lease Payments Under Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2021USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2022	$ 2,994
2023	3,491
2024	3,596
2025	3,704
2026	3,815
Thereafter	25,085
Total undiscounted lease payments	42,685
Less: imputed interest	(10,574)
Total operating lease liability as of December 31, 2021	$ 32,111

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued expenses and other current liabilities:
Accrued research and development	$ 6,863	$ 3,799
Accrued compensation and benefits	5,084	3,724
Accrued professional fees	1,246	1,532
Other	413	469
Total accrued expenses and other current liabilities	$ 13,606	$ 9,524

Collaboration and License Agr_3

Collaboration and License Agreements - Additional Information (Details)	Dec. 22, 2018USD ($)Target	Sep. 30, 2021USD ($)	Aug. 31, 2021	May 31, 2021USD ($)	Dec. 31, 2018USD ($)TargetProtein	Dec. 31, 2021USD ($)TargetPerformanceobligationTargetProtein	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price recognized as collaboration revenue						$ 34,363,000	$ 17,570,000	$ 11,948,000
Transaction price allocated to performance obligation						$ 65,322,000
Restated Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of potential targets | Target	5
Additional upfront consideration received	$ 40,000,000
Annual research plan payments receivables	$ 1,000,000
Annual research plan payments periods	3 years
Collaboration description						The collaboration is managed by a joint research committee. The Company has control over the committee and may terminate the Roche Agreement on a target-by-target or product-by-product basis under several scenarios, upon at least 90 days’ prior written notice.
Restated Roche Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Option exercise fees	$ 7,000,000
Restated Roche Agreement | Minimum | Research, Development and Commercial Milestone Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive	260,000,000
Restated Roche Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Option exercise fees	20,000,000
Restated Roche Agreement | Maximum | Research, Development and Commercial Milestone Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive	275,000,000
Restated Roche Agreement | Maximum | One-Time Sales-Based Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive	150,000,000
Restated Roche Agreement | Lead Series Identification Achievement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees	2,000,000
Restated Roche Agreement | Good Laboratory Practice (“GLP”) Toxicology (“Tox”) Study Phase
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees	$ 3,000,000
Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price recognized as collaboration revenue						$ 65,300,000
Roche Agreement | Research and Development Target and Option Right
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price recognized as collaboration revenue						$ 12,600,000
Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targets | Target						5
Agreement date					2018-12
Research agreement, period					54 months
Additional payment on extension of contract					$ 62,500,000
Nonrefundable upfront payment						$ 45,000,000
Number of performance obligation | Performanceobligation						1
Number of additional targets | Target						2
Biogen License Agreement | Research and Development Services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price recognized as collaboration revenue						$ 55,000,000
Transaction price allocated to performance obligation						30,600,000
Milestone earned						$ 6,000,000	$ 4,000,000
Biogen License Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement						90 days
Biogen License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targeted protein degradation | Protein					5
Additional targets for development | Target					5
Biogen License Agreement | Maximum | One-Time Sales-Based Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						$ 26,000,000
Biogen License Agreement | Maximum | Research And Development Milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						$ 35,000,000
Calico License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targets | Target						5
Number of performance obligation | Performanceobligation						1
Research term						5 years
Upfront payment						$ 5,000,000
Annual Payments						$ 5,000,000
Research extend term			1 year
Amount payable for extend research term option		$ 1,000,000
Initial contractual term on straight line basis						5 years
Contractual term						6 years
Additional transaction price allocated to performance obligation				$ 1,000,000
Calico License Agreement | Research and Development Services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price recognized as collaboration revenue						$ 13,000,000
Transaction price allocated to performance obligation						$ 2,700,000
Calico License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of target proteins | TargetProtein						5
Calico License Agreement | Maximum | One-Time Sales-Based Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						$ 65,000,000
Calico License Agreement | Maximum | Potential Research, Development and Commercial Milestone Payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						132,000,000
Calico License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligation						$ 63,800,000

Collaboration and License Agr_4

Collaboration and License Agreements - Summary of Allocation of Total Transaction price and Unsatisfied Transaction Price (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocated	$ 65,322
Transaction Price Unsatisfied	30,484
Research and Development Targets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocated	58,628
Transaction Price Unsatisfied	26,996
Option Rights
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction Price Allocated	6,694
Transaction Price Unsatisfied	$ 3,488

Collaboration and License Agr_5

Collaboration and License Agreements - Schedule of Revenue from Collaboration Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	$ 45,785	$ 33,195	$ 21,381
Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	19,379	9,051	6,409
Biogen Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	15,720	9,913	2,432
Calico Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue from collaboration agreements	$ 10,686	$ 14,231	$ 12,540

Collaboration and License Agr_6

Collaboration and License Agreements - Schedule of Financial Information Related to Collaboration and License Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts Receivable	$ 5,716	$ 4,484
Deferred Revenue, Current	31,800	27,603
Deferred Revenue, Net of Current	24,368	53,617
Deferred Revenue, Total	56,168	81,220
Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts Receivable	1,215	750
Deferred Revenue, Current	5,601	11,238
Deferred Revenue, Net of Current	17,215	26,991
Deferred Revenue, Total	22,816	38,229
Biogen Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts Receivable	3,000	776
Deferred Revenue, Current	24,032	13,965
Deferred Revenue, Net of Current	6,611	26,026
Deferred Revenue, Total	30,643	39,991
Calico Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts Receivable	1,501	2,958
Deferred Revenue, Current	2,167	2,400
Deferred Revenue, Net of Current	542	600
Deferred Revenue, Total	$ 2,709	$ 3,000

Collaboration and License Agr_7

Collaboration and License Agreements - Schedule of Other Financial Information Related to Collaboration and License Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Transaction price recognized as collaboration revenue	$ 34,363	$ 17,570	$ 11,948
Revenue recognized from performance obligations fully or partially satisfied in previous periods	$ 1,654	$ 348

Long-term Debt and Warrant - _2

Long-term Debt and Warrant - Related Party - Additional Information (Details) - USD ($)	Jun. 05, 2020	Dec. 31, 2021	Sep. 30, 2021
Common Stock
Long Term Debt And Warrant Liability [Line Items]
Exercise price per share		$ 8.86
Common Stock | Maximum
Long Term Debt And Warrant Liability [Line Items]
Warrant issued to purchase shares		338,784
Term Loan | Common Stock
Long Term Debt And Warrant Liability [Line Items]
Exercise price per share		$ 8.86
Term Loan | Common Stock | Maximum
Long Term Debt And Warrant Liability [Line Items]
Warrant issued to purchase shares		338,784
Credit Agreement with Perceptive Life Sciences Master Fund LTD | Term Loan
Long Term Debt And Warrant Liability [Line Items]
Aggregate principal borrowing amount	$ 20,000,000
Description of Variable Rate Basis		greater of LIBOR or 1.75%, plus 9.50
Applicable margin rate	9.50%
Interest at variable rate		11.25%
Date until which interest only payments are made	Dec. 5, 2022
Maturity date	Jun. 5, 2024
Percentage of principal payments until maturity	2.00%
Prepayment fee		$ 2,900,000
Credit Agreement with Perceptive Life Sciences Master Fund LTD | Term Loan | Minimum
Long Term Debt And Warrant Liability [Line Items]
Balance to be maintained in bank account while debt is outstanding	$ 3,000,000
Credit Agreement with Perceptive Life Sciences Master Fund LTD | Term Loan | Tranche One
Long Term Debt And Warrant Liability [Line Items]
Aggregate principal borrowing amount	12,500,000
Amount withdrawn			$ 12,500,000
Credit Agreement with Perceptive Life Sciences Master Fund LTD | Term Loan | Tranche Two
Long Term Debt And Warrant Liability [Line Items]
Aggregate principal borrowing amount	$ 7,500,000

Long-term Debt and Warrant - _3

Long-term Debt and Warrant - Related Party - Summary of Anticipated Future Minimum Payments of Long-term Debt (Details) $ in Thousands	Dec. 31, 2021USD ($)
Long Term Debt By Maturity [Abstract]
2023	$ 3,000
2024	9,500
Total minimum long-term debt payments	12,500
Less: Unamortized debt issuance costs and debt discount related to warrant	(1,732)
Total long-term debt—related party as of December 31, 2021	$ 10,768

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Details)	Dec. 31, 2021USD ($)$ / sharesshares	Oct. 06, 2020$ / sharesshares	Sep. 25, 2020	Nov. 30, 2021USD ($)	Jun. 30, 2021USD ($)shares	May 31, 2021USD ($)shares	Jul. 31, 2020USD ($)shares	Jun. 30, 2020USD ($)shares	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Oct. 31, 2020$ / sharesshares
Stockholders Equity [Line Items]
Common stock, par value per share | $ / shares	$ 0.0001								$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000								10,000,000	0	10,000,000
Common stock, shares authorized	150,000,000								150,000,000	150,000,000	150,000,000
Common stock voting right									one vote for each share
Reverse stock split			one-for-8.4335						one-for-8.4335
Stock split conversion ratio			0.118574732						0.118574732
Proceeds from follow-on public offering | $									$ 169,465,000
Proceeds from issuance of convertible preferred stock | $										$ 145,525,000
Stock issuance costs | $									$ 11,300,000
Preferred stock, outstanding	0								0	0
Issuance and sale of common stock | $										$ 191,173,000
Series B Convertible Preferred Stock
Stockholders Equity [Line Items]
Shares issued price per share | $ / shares	$ 1.05								$ 1.05
Proceeds from issuance of convertible preferred stock | $							$ 4,500,000	$ 145,500,000	$ 150,000,000
Redeemable convertible preferred stock, shares issued	142,857,142						4,285,714	138,571,428	142,857,142
Stock issuance costs | $								$ 4,500,000
IPO
Stockholders Equity [Line Items]
Initial public offering closing date		Oct. 6, 2020
Outstanding shares of preferred stock automatically converted		30,355,379
Number of preferred stock converted in to one common stock		8.4335
Preferred stock, outstanding	0								0	0
At-the-market Offerings | Equity Distribution Agreement with Cowen and Company, LLC
Stockholders Equity [Line Items]
Issuance and sale of common stock | $	$ 0
At-the-market Offerings | Maximum | Equity Distribution Agreement with Cowen and Company, LLC
Stockholders Equity [Line Items]
Issuance and sale of common stock | $				$ 200,000,000
Common Stock
Stockholders Equity [Line Items]
Issued shares of common stock										11,040,000
Exercise price per share | $ / shares	$ 8.86								$ 8.86
Number of shares withhold equivalent to aggregate exercise price | $						$ 3,000,000
Shares issued upon warrant exercise - related party, Shares						256,038			256,038
Issuance and sale of common stock | $										$ 1,000
Common Stock | Maximum
Stockholders Equity [Line Items]
Warrant issued to purchase shares	338,784								338,784
Common Stock | IPO
Stockholders Equity [Line Items]
Initial public offering closing date		Oct. 6, 2020
Issued shares of common stock		11,040,000
Shares issued price per share | $ / shares		$ 19
Outstanding shares of preferred stock automatically converted		30,355,379
Common Stock | Follow-on Public Offering
Stockholders Equity [Line Items]
Issued shares of common stock					4,887,500
Proceeds from follow-on public offering | $					$ 169,500,000
Underwriters for IPO Exercised in full Overallotment Option | Common Stock | IPO
Stockholders Equity [Line Items]
Issued shares of common stock		1,440,000
Underwriters for IPO Exercised in full Overallotment Option | Common Stock | Follow-on Public Offering
Stockholders Equity [Line Items]
Issued shares of common stock					637,500

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ in Thousands	Dec. 30, 2021	Mar. 03, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 28, 2022	Jan. 31, 2022	Jan. 01, 2022	Oct. 31, 2020	Sep. 30, 2020	Dec. 28, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares authorized			150,000,000	150,000,000					150,000,000
Payments for repurchase of common stock		$ 100		$ 194	$ 30
Payments for relinquishment of right to purchase common stock upon exercise of stock options		$ 700
Stock-based compensation, common stock shares outstanding			48,688,875	43,059,632
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, options vesting description			Vesting of the RSUs are contingent upon the determination of achievement of certain discovery and clinical milestones, or as specified market conditions are met.
Share-based compensation, number of common stock issuable per RSU vested			1
Subsequent Event | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, shares authorized for issuance						563,500	563,500
2015 Incentive Stock Option and Grant Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares reserved for issuance			9,704,418								2,525,327
Stock-based compensation, options vesting description			Options granted under the 2015 Plan generally vest over a period of five or eight years with a cliff vesting at one year and quarterly vesting thereafter and options that lapse or are forfeited are available to be granted again.
Contractual life of options from the date of grant			10 years
Stock-based compensation, common stock shares available for issuance			3,720,993
2015 Incentive Stock Option and Grant Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, options vesting period			5 years
2015 Incentive Stock Option and Grant Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, options vesting period			8 years
2020 Stock Option and Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares reserved for issuance			9,704,418							6,567,144
Stock-based compensation, common stock shares available for issuance			3,720,993
Percentage of outstanding shares of common stock	5.00%
Unrecognized compensation costs			$ 74,500
Expected to be recognized over a weighted average period			2 years 10 months 24 days
2020 Stock Option and Incentive Plan | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares authorized								2,434,443
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares reserved for issuance			861,765
Percentage of outstanding shares of common stock	1.00%
Maximum authorized payroll deduction percentage of eligible compensation for eligible employees			15.00%
Shares issued under employee stock purchase plan			6,640
Stock-based compensation, common stock shares outstanding	656,714
2020 Employee Stock Purchase Plan | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation, common stock shares authorized								486,888

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 21,512	$ 3,432	$ 1,642
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	7,526	972	395
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 13,986	$ 2,460	$ 1,247

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock Option Activity (Details) - 2020 Stock Option and Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options, Outstanding as of December 31, 2020	5,029,364
Number of options, Granted	1,926,579
Number of options, Exercised	(474,850)
Number of options, Forfeited/expired	(497,668)
Number of options, Outstanding as of December 31, 2021	5,983,425	5,029,364
Number of options, Exercisable as of December 31, 2021	1,362,477
Number of options, Vested and expected to vest as of December 31, 2021	5,983,425
Weighted-average exercise price, Outstanding as of December 31, 2020	$ 12.72
Weighted-average exercise price, Granted	41.71
Weighted-average exercise price, Exercised	4.91
Weighted-average exercise price, Forfeited/expired	16.91
Weighted-average exercise price, Outstanding as of December 31, 2021	22.33	$ 12.72
Weighted-average exercise price, Exercisable as of December 31, 2021	16.86
Weighted-average exercise price, Vested and expected to vest as of December 31, 2021	$ 22.33
Weighted average remaining contractual term (in years), Options outstanding	8 years 7 months 20 days	9 years 3 months
Weighted average remaining contractual term (in years), Options exercisable	8 years 1 month 6 days
Weighted average remaining contractual term (in years), Vested and expected to vest	8 years 7 months 20 days
Aggregate intrinsic value, Outstanding	$ 75,538	$ 102,635
Aggregate intrinsic value, Exercisable as of December 31, 2021	22,699
Aggregate intrinsic value, Vested and expected to vest as of December 31, 2021	$ 75,538

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Other Information Related to the Option Activity (Details) - 2020 Stock Option and Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average fair value of options granted	$ 29.54	$ 9.24	$ 4.13
Intrinsic value of options exercised (in thousands)	$ 17,321	$ 2,587	$ 337

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of Significant Assumptions Used in the Black-scholes Pricing Model to Determine the Fair Value of Stock Options Granted (Details) - 2020 Stock Option and Incentive Plan	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)			6 years 4 months 6 days
Risk-free interest rate, Minimum	0.59%	0.32%	1.71%
Risk-free interest rate, Maximum	1.34%	0.57%	2.36%
Expected volatility, Minimum	80.45%	69.54%	65.50%
Expected volatility, Maximum	86.20%	83.76%	76.80%
Expected dividend yield	0.00%	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	5 years 6 months	5 years 2 months 23 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life (years)	6 years 1 month 9 days	6 years 4 months 6 days

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax (Benefit) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Current tax provision:
Current federal provision	$ (673)	$ 669
Current state provision	47	135
Total current provision	(626)	804
Deferred tax provision:
Total tax provision	$ (626)	$ 804

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Expected Income Tax (Benefit) Expense (Benefit) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax benefit computed at federal statutory tax rate	21.00%	21.00%	21.00%
Stock-based compensation	(1.30%)	(0.10%)	(0.40%)
State tax—net of federal	6.00%	11.20%	6.50%
State credits	1.70%	1.20%	0.60%
Federal credits	3.10%	3.50%	1.10%
Valuation allowance	(30.20%)	(34.10%)	(32.10%)
Net operating loss carryback benefits		1.00%
Tax attributes true up due to net operating loss carryback		(1.00%)
Other permanent differences	(0.30%)	(1.80%)	0.90%
Total	0.00%	0.90%	(2.40%)

Income Taxes - Summary of Signi

Income Taxes - Summary of Significant Components of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Capitalized start-up costs	$ 875	$ 1,075
Operating lease liability	9,290	3,859
Stock-based compensation	3,675	1,344
Net operating losses	46,339	19,399
R&D and investment tax credits	9,560	5,578
Unrealized gain/loss	195
Deferred revenue	15,053	23,157
Other	426	168
Total gross deferred tax assets	85,413	54,580
Deferred tax liabilities:
Right-of-use asset	(9,242)	(3,967)
Fixed assets	(725)	(744)
Unrealized gain/loss		(3)
Less: valuation allowance	$ (75,446)	$ (49,866)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Income Tax [Line Items]
Deferred tax assets, valuation allowance	$ 75,446,000	$ 49,866,000
Net valuation allowance increases	25,600,000
Federal net operating loss carryforwards	$ 152,200,000	59,700,000
Tax credit carryforward, description	The Tax Cuts and Jobs Act, or TCJA, which was enacted in December 2017, will generally allow federal losses generated after 2017 to be carried over indefinitely, but will generally limit the NOL deduction to the lesser of the NOL carryover or 80% of a corporation’s taxable income (subject to Section 382 of the Internal Revenue Code of 1986, as amended, or IRC).
Federal net operating loss carryforwards do not expire	$ 152,200,000
Percentage of taxable income limitation under TCJA	0.80
State net operating loss carryforwards	$ 216,800,000	106,300,000
Accrued interest or penalties related to uncertain tax benefits	$ 0	0
Internal Revenue Service (IRS)
Income Tax [Line Items]
Net operating loss and tax credit carryforwards description	Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50%
Net operating loss carryforwards limited and expire due to ownership changes	$ 0
Domestic Tax Authority | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforwards	7,300,000	4,700,000
State and Local Jurisdiction | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforwards	$ 2,900,000	$ 1,100,000

Loss Per Share - Schedule of Co

Loss Per Share - Schedule of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	5,983,425	5,368,148	15,727,041
Series Seed Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities			474,298
Series A Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities			12,941,857
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities	5,983,425	5,029,364	2,310,886
Warrant to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities		338,784

Loss Per Share - Additional Inf

Loss Per Share - Additional Information (Details)	Sep. 25, 2020	Dec. 31, 2021
Earnings Per Share [Abstract]
Reverse stock split	one-for-8.4335	one-for-8.4335
Stock split conversion ratio	0.118574732	0.118574732

Loss Per Share - Schedule of Ba

Loss Per Share - Schedule of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (83,892)	$ (66,335)	$ (34,099)
Accrual of preferred stock dividends			(8,468)
Net loss attributable to common stockholders—basic and diluted	$ (83,892)	$ (66,335)	$ (42,567)
Denominator:
Weighted-average common stock outstanding - basic and diluted	46,041,733	11,370,328	1,371,905
Net loss per share attributable to common stockholders—basic and diluted	$ (1.82)	$ (5.83)	$ (31.03)

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Details) - 401(k) Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Pre-tax compensation of employees	90.00%
Percentage of employer discretion contribution	100.00%
Defined benefit plan, contributions by employer	$ 600	$ 500	$ 400
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer discretionary contribution amount	$ 6,000