Prelude Therapeutics (PRLD) 10-K 17 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 11, 2022	Jun. 30, 2021
Document Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-39527
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Trading Symbol	PRLD
Entity Registrant Name	PRELUDE THERAPEUTICS INC
Entity Central Index Key	0001678660
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-1384762
Entity Address, Address Line One	200 Powder Mill Road
Entity Address, City or Town	Wilmington
Entity Address, State or Province	DE
Entity Address, Postal Zip Code	19803
City Area Code	302
Local Phone Number	467-1280
Entity Common Stock, Shares Outstanding		47,631,741
ICFR Auditor Attestation Flag	false
Entity Public Float			$ 343.3
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Philadelphia, Pennsylvania
Documents Incorporated by Reference	Portions of the Registrant’s Definitive Proxy Statement (“Proxy Statement”) relating to the 2022 Annual Meeting of Stockholders will be filed with the Commission within 120 days after the end of the Registrant’s 2021 fiscal year pursuant to Regulation 14A and is incorporated by reference into Part III of this Report. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 31,828	$ 218,309
Marketable securities	259,405
Prepaid expenses and other current assets	3,882	2,500
Total current assets	295,115	220,809
Restricted cash	4,044
Property and equipment, net	3,929	2,480
Right-of-use asset	1,707
Other assets	303	301
Total assets	305,098	223,590
Current liabilities:
Accounts payable	7,840	3,920
Accrued expenses and other current liabilities	9,621	7,455
Operating lease liability	1,740
Total current liabilities	19,201	11,375
Other liabilities		32
Total liabilities	19,201	11,407
Commitments (note 8)
Stockholders’ equity:
Additional paid-in capital	505,723	319,605
Accumulated other comprehensive income (loss)	(711)
Accumulated deficit	(219,120)	(107,426)
Total stockholders’ equity	285,897	212,183
Total liabilities and stockholders’ equity	305,098	223,590
Voting Common Stock
Stockholders’ equity:
Common stock	4	3
Non-voting Common Stock
Stockholders’ equity:
Common stock	$ 1	$ 1

BALANCE SHEETS (PARENTHETICAL)

BALANCE SHEETS (PARENTHETICAL) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Voting Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	487,149,741	487,149,741
Common stock, shares, issued	36,200,299	32,595,301
Common stock, shares, outstanding	36,200,299	32,595,301
Non-voting Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	12,850,259	12,850,259
Common stock, shares, issued	11,402,037	11,110,371
Common stock, shares, outstanding	11,402,037	11,110,371

STATEMENTS OF OPERATIONS AND CO

STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 86,778	$ 48,177
General and administrative	26,957	10,586
Total operating expenses	113,735	58,763
Loss from operations	(113,735)	(58,763)
Other income, net	2,041	1,834
Net loss	$ (111,694)	$ (56,929)
Per share information:
Net loss per share of common stock, basic and diluted	$ (2.43)	$ (4.56)
Weighted average common shares outstanding, basic and diluted	46,049,763	12,478,463
Comprehensive loss
Net loss	$ (111,694)	$ (56,929)
Unrealized gain (loss) on marketable securities, net of tax	(711)
Comprehensive loss	$ (112,405)	$ (56,929)

STATEMENTS OF CHANGES IN CONVER

STATEMENTS OF CHANGES IN CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Common StockVoting Common Stock	Common StockNon-voting Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Convertible preferred stock, Beginning balance at Dec. 31, 2019		$ 36,595	$ 29,848
Convertible preferred stock, Beginning balance (shares) at Dec. 31, 2019		11,736,119	7,628,846
Beginning balance at Dec. 31, 2019	$ (49,412)						$ 1,085		$ (50,497)
Beginning balance (shares) at Dec. 31, 2019					3,161,653
Issuance of common stock upon exercise of stock options	$ 100						100
Issuance of common stock upon exercise of stock options, (shares)	100,545				100,545
Sale of stock, net of offering costs	$ 166,630				$ 1		166,629
Sale of stock, net of offering costs, (shares)					9,573,750
Sale of convertible preferred stock, net of issuance costs			$ 29,942	$ 49,826
Sale of convertible preferred stock, net of issuance costs (shares)			7,628,846	3,443,612
Conversion of convertible preferred stock upon initial public offering	146,211	$ (36,595)	$ (59,790)	$ (49,826)	$ 2	$ 1	146,208
Conversion of convertible preferred stock upon initial public offering (shares)		(11,736,119)	(15,257,692)	(3,443,612)	19,327,052	11,110,371
Stock-based compensation expense, including issuance of RSAs	5,583						5,583
Stock-based compensation expense, including issuance of RSAs (shares)					432,301
Net loss	(56,929)								(56,929)
Ending balance at Dec. 31, 2020	212,183				$ 3	$ 1	319,605		(107,426)
Ending balance (shares) at Dec. 31, 2020					32,595,301	11,110,371
Issuance of common stock upon exercise of stock options	$ 3,504						3,504
Issuance of common stock upon exercise of stock options, (shares)	995,950				995,950
Sale of stock, net of offering costs	$ 161,412				$ 1		161,411
Sale of stock, net of offering costs, (shares)					2,583,334	291,666
Issuance of common stock under ESPP	272						272
Issuance of common stock under ESPP, (shares)					25,714
Unrealized gain (loss) on marketable securities, net of tax	(711)							$ (711)
Stock-based compensation expense, including issuance of RSAs	20,931						20,931
Net loss	(111,694)								(111,694)
Ending balance at Dec. 31, 2021	$ 285,897				$ 4	$ 1	$ 505,723	$ (711)	$ (219,120)
Ending balance (shares) at Dec. 31, 2021					36,200,299	11,402,037

STATEMENTS OF CHANGES IN CONV_2

STATEMENTS OF CHANGES IN CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (PARENTHETICAL) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Sale of common stock, offering costs	$ 739	$ 2,538
Series B Convertible Preferred Stock
Sale of common stock, offering costs		58
Series C Convertible Preferred Stock
Sale of common stock, offering costs		$ 174

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows used in operating activities:
Net loss	$ (111,694)	$ (56,929)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	915	542
Noncash lease expense	1,328
Loss on disposal of property and equipment		11
Stock-based compensation	20,931	5,583
Amortization of premium and discount on marketable securities, net	1,364
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,382)	(1,155)
Accounts payable	3,903	1,157
Accrued expenses and other liabilities	2,463	4,614
Operating lease liabilities	(1,359)
Net cash used in operating activities	(83,531)	(46,177)
Cash flows used in investing activities:
Purchases of marketable securities	(261,480)
Purchases of property and equipment	(2,323)	(621)
Net cash used in investing activities	(263,803)	(621)
Cash flows provided by financing activities:
Proceeds from the sale of common stock, net of offering costs	161,424
Proceeds from the issuance of common stock upon initial public offering, net of offering costs		166,630
Payment of offering costs	(303)	(12)
Payment of capital lease obligation		(258)
Proceeds from issuance of common stock in connection with the exercise of stock options	3,504	100
Proceeds from the issuance of common stock under ESPP	272
Net cash provided by financing activities	164,897	246,228
Net (decrease) increase in cash and cash equivalents	(182,437)	199,430
Cash, cash equivalents and restricted cash at beginning of year	218,309	18,879
Cash, cash equivalents and restricted cash at end of year	35,872	218,309
Supplemental disclosures:
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	567
Property and equipment in accounts payable	806	765
Unrealized gain (loss) on marketable securities	$ (711)
Offering costs in accrued expenses		265
Offering costs in accounts payable		24
Series C Convertible Preferred Stock
Cash flows provided by financing activities:
Proceeds from the sale of convertible preferred stock, net of offering costs		49,826
Series B Convertible Preferred Stock
Cash flows provided by financing activities:
Proceeds from the sale of convertible preferred stock, net of offering costs		$ 29,942

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations	1. Nature of Operations Prelude Therapeutics Incorporated (the “Company”) was incorporated in Delaware on February 5, 2016 and is a clinical-stage fully integrated oncology company built on a foundation of drug discovery excellence to deliver novel precision cancer medicines to underserved patients. Since beginning operations, the Company has devoted substantially all its efforts to research and development, conducting preclinical and clinical studies, recruiting management and technical staff, administration, and raising capital.

Risks and Liquidity

Risks and Liquidity	12 Months Ended
	Dec. 31, 2021
Risks And Liquidity [Abstract]
Risks and Liquidity	2. Risks and Liquidity The Company is subject to a number of risks common to early-stage companies in the biotechnology industry. Principal among these risks are the uncertainties in the development process, development of the same or similar technological innovations by competitors, protection of proprietary technology, dependence on key personnel, compliance with government regulations and approval requirements, and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products developed will obtain necessary government regulatory approval, or that any approved products will be commercially viable. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and contractors. Since its inception, the Company has incurred operating losses and had an accumulated deficit of $219.1 million at December 31, 2021. The Company has no revenue to date and devotes its efforts to research and development. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. The Company believes that its cash, cash equivalents and marketable securities as of December 31, 2021 will be sufficient to fund its operating expenses and capital expenditure requirements into the second half of 2024. To fund its operating expenses and capital expenditure requirements after that date, the Company plans to seek additional funding through public or private equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into strategic alliances or other arrangements on favorable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be required to delay, reduce or eliminate research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect its business prospects. On March 10, 2020, the World Health Organization characterized the novel COVID-19 virus as a global pandemic. There is significant uncertainty as to the likely effects of this disease and emerging variants which may, among other things, materially impact the Company’s planned clinical trials. This pandemic or outbreak could result in difficulty securing clinical trial site locations, CROs, and/or trial monitors and other critical vendors and consultants supporting the trial. In addition, outbreaks or the perception of an outbreak near a clinical trial site location could impact the Company’s ability to enroll patients. These situations, or others associated with COVID-19, could cause delays in the Company’s clinical trial plans and could increase expected costs, all of which could have a material adverse effect on the Company’s business and its financial condition. At the current time, the Company is unable to quantify the potential effects of this pandemic on its future financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with generally accepted accounting principles (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of the revisions are reflected in the accompanying financial statements in the period they are determined to be necessary. The most significant estimate relates to accrued clinical trial expenses. Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist of cash, cash equivalents, and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant credit risk beyond the normal credit risk associated with commercial banking relationships. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views and manages its operations as a single operating segment. Fair Value of Financial Instruments Management believes that the carrying amounts of the Company’s financial instruments, including cash, restricted cash, accounts payable, and accrued expenses, approximate fair value due to the short-term nature of these instruments. Cash, Cash Equivalents and Restricted cash The Company’s cash equivalents include short-term highly liquid investments with an original maturity of 90 days or less when purchased and are carried at fair value in the accompanying balance sheets. Restricted cash comprises a letter of credit for the benefit of the landlord in connection with the Company’s new lease facility. See note 8 for further details. The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the balance sheet that total to the amounts shown in the statement of cash flows: December 31, (in thousands) 2021 2020 Cash and cash equivalents $ 31,828 $ 218,309 Restricted cash 4,044 - Total cash, cash equivalents, and restricted cash shown in statement of cash flows $ 35,872 $ 218,309 Marketable Securities The Company’s marketable securities consist of investments in corporate debt securities and commercial paper that are classified as available-for-sale. The securities are carried at fair value with the unrealized gains and losses, net of tax, included in accumulated other comprehensive income (loss), a component of stockholders’ equity (deficit). Realized gains and losses and declines in value determined to be other than temporary are included in the Company’s statements of operations. The Company classifies marketable securities that are available for use in current operations as current assets on the balance sheets. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation expense is recognized using the straight-line method over the estimated useful life of the asset, ranging from 5-7 years as follows: Fixed Asset Type Estimated useful life Lab equipment 5 years Furniture and fixtures 7 years Leasehold improvements are amortized over the shorter of the estimated useful life of the assets or the remaining lease term. Assets under capital leases are recorded in property and equipment, net on the balance sheets and depreciated in a manner similar to other property and equipment. Expenditures for repairs and maintenance of assets are charged to expense as incurred, while major betterments are capitalized. Upon retirement or sale, the cost and related accumulated depreciation of assets disposed of are removed from the accounts and any resulting gain or loss is included in the statements of operations. The Company reviews long-lived assets, such as property and equipment, for impairment when events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. If indicators of impairment are present, the assets are tested for recoverability by comparing the carrying amount of the assets to the related estimated future undiscounted cash flows that the assets are expected to generate. If the expected cash flows are less than the carrying value of the asset, then the asset is considered to be impaired and its carrying value is written down to fair value, based on the related estimated discounted future cash flows. Comprehensive loss Comprehensive loss includes net loss and certain changes in stockholders’ equity (deficit) that are excluded from net loss. The Company’s comprehensive loss for the year ended December 31, 2021 comprised net loss and unrealized gain(loss) on marketable securities. The Company’s comprehensive loss was equal to net loss for the year ended December 31, 2020. Stock-Based Compensation The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. Estimating the fair value of share-based awards requires the input of subjective assumptions, including, for stock options, the expected life of the options and stock price volatility. The Company accounts for forfeitures for stock option awards as they occur. The Company uses the Black-Scholes option pricing model to value its stock option awards. The assumptions used in estimating the fair value of share-based awards represent management’s estimate and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards. The expected life of the stock options is estimated using the “simplified method”, as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The risk-free rate is based on the U.S. Treasury yield curve commensurate with the expected life of the option. Grant Income and Research and Development Tax Credits The Company recognizes grant income and Delaware research and development tax credits, which are refundable irrespective of taxable income, in other income, net in the statements of operations when it is probable that the amounts will be received and the necessary qualifying conditions, as stated in the agreements, are met. Research and Development Research and development costs are expensed as incurred. Research and development expenses consist principally of personnel costs, including salaries, stock-based compensation, and benefits of employees, and other operational costs related to the Company’s research and development activities, including allocated facility-related expenses and external costs of outside vendors, such as clinical research organizations and clinical manufacturing organizations, and other direct and indirect costs. Management makes estimates of the Company’s accrued research and development expenses as of each balance sheet date in the Company’s financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed. Income Taxes Income taxes are accounted for under the asset-and-liability method as required by FASB ASC Topic 740, Income Taxes FASB ASC Subtopic 740-10, Accounting for Uncertainty of Income Taxes Net Loss Per Share Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during each period. The weighted-average number of shares of common stock outstanding used in the basic net loss per share calculation does not include unvested restricted stock awards as these instruments are considered contingently issuable shares until they vest. Diluted net loss per share of common stock includes the effect, if any, from the potential exercise of stock options, and the effect from unvested restricted stock awards and restricted stock units which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive. The Company’s unvested restricted stock awards entitles the holder to participate in dividends and earnings of the Company, and, if the Company were to recognize net income, it would have to use the two-class method to calculate earnings per share. The two-class method is not applicable during periods with a net loss, as the holders of the unvested restricted stock awards have no obligation to fund losses. The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: December 31, 2021 2020 Unvested restricted stock awards 611,608 1,214,767 Unvested restricted stock units 20,000 — Stock options 7,179,482 6,839,091 7,811,090 8,053,858 Amounts in the above table reflect the common stock equivalents. Recently Issued Accounting Pronouncements Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Adopted Accounting Pronouncements On January 1, 2021, the Company adopted ASC 842 issued by the FASB in February 2016, which was subsequently supplemented by clarifying guidance to improve financial reporting of leasing transactions. The new lease accounting guidance requires lessees to recognize lease liabilities and right-of-use assets on the balance sheet for all leases with initial terms longer than 12 months and provides enhanced disclosures on key information of leasing arrangements. The Company adopted the new standard using the modified retrospective transition method utilizing the optional transition method and elected the package of practical expedients. Accordingly, prior periods were not restated to reflect the adopted standard. In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g., land, building, etc.), non-lease components (e.g., common area maintenance, maintenance, consumables, etc.), and non-components (e.g., property taxes, insurance, etc.). The Company has elected the practical expedient to account for the lease and non-lease components of each of its operating leases as a single lease component and allocate all of the contract consideration to the lease component only. Upon adoption, the Company recorded a right of use asset of $2.5 million and corresponding operating lease liabilities of $2.5 million, with an offset to accrued expenses and other current liabilities of approximately $64,000 to eliminate deferred rent on the balance sheets. At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term including any options to extend the lease that the Company is reasonably certain to exercise. The Company calculates the present value of lease payments using an incremental borrowing rate as the Company’s leases do not provide an implicit interest rate. The Company’s incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (“Short-Term Leases”). For Short-Term Leases, the Company records the rent expense on a straight-line basis and does not record the leases on the balance sheet. The Company entered into a short-term lease in June 2021 and elected the short-term lease exemption that allows the Company to record the rent expense on a straight-line basis and does not require the recognition of a right-of-use asset or corresponding operating lease liability. Refer to Note 8 for the Company’s lease disclosures. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement and (ii) the right-of-use lease asset based on the re-measured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received, and any initial direct costs incurred are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term. The adoption of the new lease accounting standard did not have a material impact on the Company’s results of operations or cash flows for the year ended December 31, 2021. Accounting guidance not yet adopted In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments ” which has subsequently been amended by ASU No. 2019-04, ASU No. 2019-05, ASU No. 2019-10, ASU No. 2019-11, and ASU No. 2020-03 (“ASU 2016-03”). This guidance replaces the incurred loss impairment methodology under current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This guidance is effective for the Company for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2022 and must be adopted using a modified retrospective approach, with certain exceptions. The Company is currently evaluating the impact of this standard on its financial statements and related disclosures. In November 2021, the FASB issued ASU No. 2021-10, “Government Assistance: Disclosures by Business Entities about Government Assistance” . The amendments in this Update improve financial reporting by requiring disclosures that increase the transparency of transactions with a government. The amendments require the following annual disclosures about transactions with a government that are accounted for by applying a grant or contribution accounting model by analogy (i) the type of transaction (ii) the accounting for the transaction, and (iii) the effect of the transaction on the entity’s financial statements. This guidance is effective for the Company for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021 with early adoption permitted. The Company is currently evaluating the impact of this standard but does not expect that it will have a material impact on its financial statements and related disclosures.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Investments	4. Marketable Securities The following is a summary of the Company’s marketable securities as of December 31, 2021. The Company did not have any marketable securities as of December 31, 2020. (in thousands) Amortized Cost Gross unrealized gain Gross unrealized loss Fair Value Marketable securities Corporate debt securities $ 193,798 $ 1 $ (696 ) $ 193,103 Commercial paper 66,318 1 (17 ) 66,302 $ 260,116 $ 2 $ (713 ) $ 259,405 The Company’s marketable securities generally have contractual maturity dates of 18 months or less. As of December 31, 2021, the Company had 25 securities with a total fair market value of $221.8 million in an unrealized loss position. The Company believes that any unrealized losses associated with the decline in value of its securities is temporary and is primarily related to the change in market interest rates since purchase and believes that it is more likely than not that it will be able to hold its debt securities to maturity

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	5. Fair Value of Financial Instruments Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments be made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The Company follows the provisions of ASC 820, for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories: • Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. • Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liabilities. • Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis: Fair value measurement at reporting date using (in thousands) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) December 31, 2021: Assets: Cash equivalents (Money Market Funds) $ 30,520 $ — $ — Marketable securities Corporate debt securities — 193,103 — Commercial paper — 66,302 — Total 30,520 259,405 — December 31, 2020: Assets: Cash equivalents (Money Market Funds) $ 217,072 $ — $ —

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment consisted of the following: December 31, (in thousands) 2021 2020 Lab equipment $ 4,266 $ 3,010 Leasehold improvements 875 448 Furniture and fixtures 118 105 Construction in progress 668 — 5,927 3,563 Less accumulated depreciation (1,998 ) (1,083 ) Property and equipment, net $ 3,929 $ 2,480 In September 2019, the Company signed a 12-month capital lease for $0.4 million of lab equipment with an effective interest rate of 9.67%. At December 31, 2020, the Company had $0.1 million of accumulated amortization related to the capital lease. At December 31, 2020, the Company had no further lease payments under the capital lease.

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	7. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: December 31, (in thousands) 2021 2020 Compensation and related benefits $ 4,919 $ 3,614 Research and development 4,615 3,421 Other 87 420 $ 9,621 $ 7,455

Commitments

Commitments	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments	8. Commitments Leases The Company leases office and laboratory space in Wilmington, Delaware under a noncancelable lease (the “Lease”), which expires in December 2022. The Lease was amended during the third quarter of 2021 to include additional office and laboratory space to accommodate the Company’s growth. The Company has an option to renew the Lease for an additional 1-year period. . The future minimum lease payments under the Lease at December 31, 2021 are as follows: (in thousands) 2022 $ 1,836 Total undiscounted lease payments 1,836 Less imputed interest (96 ) Current lease liability $ 1,740 During the fourth quarter of 2021, the Company the date the Company takes possession of the premises for the conduct of the Company’s business (the Commencement Date). The Chestnut Run Lease premises includes approximately 81,000 square feet, located at Chestnut Run Plaza in Wilmington, Delaware (the Premises). The Premises contains both office and lab space the Company intends to use for administrative, research and development and other activities. Upon the Chestnut Run Lease commencement, the Company will recognize a right-of-use asset and operating lease liability in accordance with ASC 842. The Chestnut Run Lease has an initial term of 162 months with 3 five-year (in thousands) 2022 $ - 2023 840 2024 2,141 2025 2,350 2026 2,409 Thereafter 26,098 The Company paid a security deposit in the form of a letter of credit of $4.0 million which is included in the balance sheet as restricted cash as of December 31, 2021. The security deposit may be reduced to $0.5 million over time in accordance with the terms of the Chestnut Run Lease In June 2021, the Company entered into a 12-month noncancelable lease, which commenced on July 1, 2021 and will expire on June 30, 2022, and has remaining lease payments of approximately $0.2 million in 2022. The Company adopted the short-term lease election as afforded by ASC 842 and did not recognize a right-of-use asset and operating lease liability related to this short-term lease. Rent expense for the years ended December 31, 2021 and 2020 was $1.8 million and $1.2 million, respectively. Employment Agreements The Company entered into employment agreements with key personnel providing for compensation and severance in certain circumstances, as defined in the respective employment agreements. 401(k) Defined Contribution Plan The Company sponsors a 401(k) defined‑contribution plan covering all employees. Participants are permitted to contribute up to 100% of their eligible annual pretax compensation up to an established federal limit on aggregate participant contributions. The Company provides a safe harbor match with a maximum amount of 3% of the participant’s compensation. During 2021 the Company made matching contributions of $0.5 million. The Company did not make any matching contributions in 2020. Research Collaboration Agreement In September 2021, the Company entered into a research collaboration agreement estimated to last for approximately one year (the “Darwin Health Agreement”) with Darwin Health, Inc. (“DarwinHealth”). Under the terms of the Darwin Health Agreement, DarwinHealth will utilize their drug discovery technologies and certified methodologies in precision oncology to advance and accelerate clinical development for certain of the Company’s programs across a broad range of tumor subtypes. The Company will pay DarwinHealth a total of $3.0 million in three equal installments over the one-year eighteen-months Other Research and Development Arrangements The Company enters into agreements with contract research organizations (“CROs”) to assist in the performance of research and development activities. Expenditures to CROs will represent a significant cost in clinical development for the Company.

Convertible Preferred Stock and

Convertible Preferred Stock and Common Stock	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Convertible Preferred Stock and Common Stock	9. Convertible Preferred Stock and Common Stock Preferred Stock Financings In May 2019, the Company issued an aggregate of 7,628,846 shares of Series B convertible preferred stock (“Series B”) to existing investors at $3.9325 per share for aggregate net proceeds of $29.8 million. Pursuant to the Series B Stock Purchase Agreement, the Series B investors could elect to purchase an aggregate of 7,628,846 additional shares of the Company’s Series B at a fixed purchase price of $3.9325 per share (the “Series B Future Tranche Right”). The Company determined that the Series B Future Tranche Right did not meet the definition of a freestanding financial instrument as it was not legally detachable. The Series B Future Tranche Right was also evaluated as an embedded derivative and the Company determined it did not meet the definition of a derivative instrument for which bifurcation would be required. In March 2020, the Company’s Series B investors exercised their Future Tranche Right and purchased 7,628,846 shares of Series B for net proceeds of approximately $29.9 million. In August 2020, the Company’s existing Convertible Preferred Stock investors as well as a new investor purchased 3,443,612 shares of Series C at a price of $14.5197 per share for net proceeds of approximately $49.8 million. Initial Public Offering In September 2020, the Company completed its IPO in which the Company sold 9,573,750 shares of its common stock at a public offering price of $19.00 per share. The Company received net proceeds of $166.6 million after deducting underwriting discounts, commissions, and other offering expenses paid by the Company. In addition, immediately prior to the closing of the IPO on September 29, 2020, (i) all of the Company’s outstanding shares of convertible preferred stock converted into an aggregate of 30,437,423 shares of common stock (of which, 11,110,371 shares are non-voting common stock) and (ii) the Company filed an amended and restated certificate of incorporation to, among other things, increase the number of authorized shares of common stock to 500,000,000. Follow-on Offering In January 2021, the Company sold 2,875,000 shares of its common stock at a public offering price of $60.00 per share. The Company received net proceeds of $161.4 million after deducting underwriting discounts, commissions, and other offering expenses paid by the Company. Common Stock The Company has two classes of common stock; “voting common stock” and “non-voting common stock.” The holders of the voting common stock are entitled to one vote for each share of voting common stock held at all meetings of stockholders. Except as otherwise required by law, the holders of non-voting common stock shall not be entitled to vote at any meetings of stockholders (or written actions in lieu of meetings) and the shares of non-voting common stock shall not be included in determining the number of shares voting or entitled to vote on any matter. Unless required by law, there shall be no cumulative voting. Any holder of non-voting common stock may elect to convert each share of non-voting common stock into one fully paid and non-assessable share of voting common stock at any time by providing written notice to the Company; provided that as a result of such conversion, such holder, together with its affiliates and any members of a Schedule 13(d) group with such holder, would not beneficially own in excess of 9.99% of the Company’s common stock immediately prior to and following such conversion, unless otherwise as expressly provided for in the Company’s restated certificate of incorporation. However, this ownership limitation may be increased (not to exceed 19.99%) or decreased to any other percentage designated by such holder of non-voting common stock upon 61 days’ notice to the Company.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	10. Stock-Based Compensation The Company has two equity incentive plans: the 2016 Equity Incentive Plan, as amended, and the 2020 Equity Incentive Plan. New awards can only be granted under the 2020 Equity Incentive Plan (the “Plan”). The total number of shares initially authorized under the Plan was 4,680,000, which was increased on January 1, 2021 and will automatically increase on January 1st of each year, continuing for ten years, in an amount equal to five percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year. At December 31, 2021, 5,314,849 shares were available for future grants and on January 1, 2022, 2,380,116 shares were added to the Plan. The Plan provides for the granting of common stock, incentive stock options, nonqualified stock options, restricted stock awards, restricted stock units and/or stock appreciation rights to employees, directors, and other persons, as determined by the Company’s board of directors. The Company’s stock options vest based on the terms in each award agreement, generally over four-year periods with 25% of options vesting after 1 year and then monthly thereafter, and have a term of ten years . The Company measures stock-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. The Company recorded stock-based compensation expense in the following expense categories in its accompanying statements of operations: Year Ended December 31, (in thousands) 2021 2020 Research and development $ 9,469 $ 2,585 General and administrative 11,462 2,998 $ 20,931 $ 5,583 Stock Options The following table summarizes stock option activity for the Plan in the years indicated: Number of shares Weighted average exercise price per share Weighted average remaining contractual term (years) Outstanding at January 1, 2020 2,269,742 $ 1.66 9.20 Granted 4,785,630 $ 11.35 Exercised (100,545 ) $ 0.99 Forfeited (115,736 ) $ 1.37 Outstanding at December 31, 2020 6,839,091 $ 8.46 9.17 Granted 2,600,231 $ 31.14 Exercised (995,950 ) $ 3.52 Forfeited (1,263,890 ) $ 19.79 Outstanding at December 31, 2021 7,179,482 $ 15.36 8.66 Exercisable at December 31, 2021 2,057,975 $ 6.99 8.04 At December 31, 2021, the aggregate intrinsic value of outstanding options and exercisable options was $25.1 million and $13.2 million, respectively. The following table summarizes information about stock options outstanding and exercisable at December 31, 2021 under the Plan: Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (in years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $0.31 - $7.37 2,352,647 7.76 $ 1.80 1,233,638 $ 1.75 $7.38 - $13.08 2,465,488 8.67 12.85 777,587 12.85 $13.09 - $31.30 1,760,632 9.61 27.58 4,219 17.99 $31.31 - $88.98 600,715 9.35 43.02 42,531 50.79 7,179,482 2,057,975 The weighted-average grant date fair value of options granted was $22.80 and $10.12 per share for the years ended December 31, 2021 and 2020, respectively. The aggregate intrinsic value of options exercised was $26.9 million for the year ended December 31, 2021 . The Company recorded stock-based compensation expense of $ 19.9 million and $ million for the years ended December 31, 2021 and 2020 , respectively, related to stock options. As of December 31, 2021 , the total unrecognized compensation expense related to unvested stock option awards was $ million, which the Company expects to recognize over a weighted-average period of 3.03 years . The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below: Year Ended December 31, 2021 2020 Expected volatility 87.46 % 115.17 % Risk-free interest rate 0.94 % 0.43 % Expected life (in years) 6.04 6.25 Expected dividend yield — — Restricted Stock Awards and Units The Company issues restricted stock awards (“RSA”) to employees that generally vest over a four-year The following table summarizes activity related to RSA stock-based payment awards: Number of shares Weighted- average grant date fair value Unvested balance at January 1, 2020 1,335,349 $ 1.42 Granted 432,301 $ 3.26 Vested (552,883 ) $ 1.37 Unvested balance at December 31, 2020 1,214,767 $ 2.09 Vested (603,159 ) $ 1.89 Unvested balance at December 31, 2021 611,608 $ 2.29 The Company recorded stock-based compensation expense of $0.9 million and $0.8 million for the years ended December 31, 2021 and 2020, respectively, related to RSAs. As of December 31, 2021, the total unrecognized expense related to all RSAs was $1.3 million, which the Company expects to recognize over a weighted-average period of 1.83 years. The Company issues restricted stock units (“RSU”) to employees that generally vest over a four-year The following table summarizes activity related to RSU stock-based payment awards: Number of shares Weighted- average grant date fair value Outstanding at January 1, 2021 — Granted 45,000 $ 26.91 Forfeited (25,000 ) $ 33.78 Outstanding at December 31, 2021 20,000 $ 18.32 The Company recorded stock-based compensation expense of $20 thousand for the year ended December 31, 2021 related to RSUs. At December 31, 2021 the total unrecognized expense related to the RSUs was $0.3 million, which the Company expects to recognize over 3.76 years. Employee Stock Purchase Plan The Company has an Employee Stock Purchase Plan (the “ESPP”), which as of December 31, 2021 had 931,342 shares of common stock reserved for future issuance. The Company issued 25,714 shares under the ESPP in 2021. The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the ESPP shall automatically increase on January 1st of each year and continuing for ten years beginning in 2021, in an amount equal to one percent of the total number of shares of all classes of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year. As such, on January 1, 2022, 476,023 shares were added to the ESPP. Under the ESPP, eligible employees can purchase the Company’s common stock through accumulated payroll deductions at such times as are established by the compensation committee. Eligible employees may purchase the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock on the first day of the offering period or on the last day of the offering period. Eligible employees may contribute up to 15% of their eligible compensation. Under the ESPP, a participant may not accrue rights to purchase more than $25,000 worth of the Company’s common stock for each calendar year in which such right is outstanding. The ESPP is considered compensatory under the FASB stock compensation rules. Accordingly, share-based compensation expense is determined based on the option’s grant-date fair value as estimated by applying the Black Scholes option-pricing model and is recognized over the withholding period. The Company recognized share-based compensation expense of $0.2 million for the year ended December 31, 2021 related to the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities were as follows: December 31, (in thousands) 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 60,495 $ 28,283 Research and development credits 11,240 4,753 Stock-based compensation 2,448 33 Accrued expense 1,290 — Lease liabilities 485 — Gross deferred tax assets 75,958 33,069 Less: valuation allowance (75,371 ) (32,899 ) Total deferred tax asset 587 170 Deferred tax liability Right-of-use assets (476 ) — Depreciation (111 ) (170 ) Total deferred tax liabilities (587 ) (170 ) Net deferred tax assets $ — $ — In assessing the need for a valuation allowance, management must determine that there will be sufficient taxable income to allow for the realization of deferred tax assets. Based upon the historical and anticipated future losses, management has determined that the deferred tax assets do not meet the more likely than not threshold for realizability. Accordingly, a full valuation allowance has been recorded against the Company’s net deferred tax assets as of December 31, 2021 and December 31, 2020 . The valuation allowance increased by $ million and $ million during the years ended December 31, 2021 and 2020 , respectively. A reconciliation of the federal income tax rate to the Company’s effective tax rate is as follows: Year ended December 31, 2021 2020 Federal tax benefit at statutory rate (21.0 )% (21.0 )% State tax, net of federal benefit (7.7 ) (6.5 ) Permanent differences (3.5 ) 1.2 Research and development (5.8 ) (4.4 ) Change in valuation allowance 38.0 30.7 — % — % The following table summarizes carryforwards of federal and state net operating losses (“NOL”) and research tax credits: December 31, (in thousands) 2021 2020 NOL carryforwards - Federal $ 217,038 $ 101,471 NOL carryforwards - State 217,038 101,471 Research tax credits - Federal 11,206 4,720 Research tax credits - State 43 43 The NOL carryforwards begin expiring in 2036 for federal and Delaware state income tax purposes, however; all federal and Delaware state NOL carryforwards generated subsequent to January 1, 2018, are able to be carried forward indefinitely. As of December 31, 2021, the Company also had federal and Delaware research and development tax credit carryforwards of $11.2 million and $43 thousand, respectively, that will begin to expire in 2036 and 2031, respectively, unless previously utilized. The NOL and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. NOL 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 Internal Revenue Code, 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. To date, the Company has not performed an analysis to determine whether or not ownership changes have occurred since inception. Delaware state NOLs may also be limited. As of December 31, 2021, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Company’s statement of operations. Due to NOL and tax credit carry forwards that remain unutilized, income tax returns for all tax years remain subject to examination by the taxing jurisdictions. The NOL carryforwards remain subject to review until utilized.

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 accompanying financial statements have been prepared in accordance with generally accepted accounting principles (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”).
Use of estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Estimates and assumptions are periodically reviewed and the effects of the revisions are reflected in the accompanying financial statements in the period they are determined to be necessary. The most significant estimate relates to accrued clinical trial expenses.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist of cash, cash equivalents, and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant credit risk beyond the normal credit risk associated with commercial banking relationships.
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views and manages its operations as a single operating segment.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Management believes that the carrying amounts of the Company’s financial instruments, including cash, restricted cash, accounts payable, and accrued expenses, approximate fair value due to the short-term nature of these instruments.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted cash The Company’s cash equivalents include short-term highly liquid investments with an original maturity of 90 days or less when purchased and are carried at fair value in the accompanying balance sheets. Restricted cash comprises a letter of credit for the benefit of the landlord in connection with the Company’s new lease facility. See note 8 for further details. The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the balance sheet that total to the amounts shown in the statement of cash flows: December 31, (in thousands) 2021 2020 Cash and cash equivalents $ 31,828 $ 218,309 Restricted cash 4,044 - Total cash, cash equivalents, and restricted cash shown in statement of cash flows $ 35,872 $ 218,309
Marketable Securities	Marketable Securities The Company’s marketable securities consist of investments in corporate debt securities and commercial paper that are classified as available-for-sale. The securities are carried at fair value with the unrealized gains and losses, net of tax, included in accumulated other comprehensive income (loss), a component of stockholders’ equity (deficit). Realized gains and losses and declines in value determined to be other than temporary are included in the Company’s statements of operations. The Company classifies marketable securities that are available for use in current operations as current assets on the balance sheets.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation expense is recognized using the straight-line method over the estimated useful life of the asset, ranging from 5-7 years as follows: Fixed Asset Type Estimated useful life Lab equipment 5 years Furniture and fixtures 7 years Leasehold improvements are amortized over the shorter of the estimated useful life of the assets or the remaining lease term. Assets under capital leases are recorded in property and equipment, net on the balance sheets and depreciated in a manner similar to other property and equipment. Expenditures for repairs and maintenance of assets are charged to expense as incurred, while major betterments are capitalized. Upon retirement or sale, the cost and related accumulated depreciation of assets disposed of are removed from the accounts and any resulting gain or loss is included in the statements of operations. The Company reviews long-lived assets, such as property and equipment, for impairment when events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. If indicators of impairment are present, the assets are tested for recoverability by comparing the carrying amount of the assets to the related estimated future undiscounted cash flows that the assets are expected to generate. If the expected cash flows are less than the carrying value of the asset, then the asset is considered to be impaired and its carrying value is written down to fair value, based on the related estimated discounted future cash flows.
Comprehensive Loss	Comprehensive loss Comprehensive loss includes net loss and certain changes in stockholders’ equity (deficit) that are excluded from net loss. The Company’s comprehensive loss for the year ended December 31, 2021 comprised net loss and unrealized gain(loss) on marketable securities. The Company’s comprehensive loss was equal to net loss for the year ended December 31, 2020.
Stock-Based Compensation	Stock-Based Compensation The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. Estimating the fair value of share-based awards requires the input of subjective assumptions, including, for stock options, the expected life of the options and stock price volatility. The Company accounts for forfeitures for stock option awards as they occur. The Company uses the Black-Scholes option pricing model to value its stock option awards. The assumptions used in estimating the fair value of share-based awards represent management’s estimate and involve inherent uncertainties and the application of management’s judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards. The expected life of the stock options is estimated using the “simplified method”, as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses comparable public companies as a basis for its expected volatility to calculate the fair value of option grants. The risk-free rate is based on the U.S. Treasury yield curve commensurate with the expected life of the option.
Grant Income and Research and Development Tax Credits	Grant Income and Research and Development Tax Credits The Company recognizes grant income and Delaware research and development tax credits, which are refundable irrespective of taxable income, in other income, net in the statements of operations when it is probable that the amounts will be received and the necessary qualifying conditions, as stated in the agreements, are met.
Research and Development	Research and Development Research and development costs are expensed as incurred. Research and development expenses consist principally of personnel costs, including salaries, stock-based compensation, and benefits of employees, and other operational costs related to the Company’s research and development activities, including allocated facility-related expenses and external costs of outside vendors, such as clinical research organizations and clinical manufacturing organizations, and other direct and indirect costs. Management makes estimates of the Company’s accrued research and development expenses as of each balance sheet date in the Company’s financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are performed.
Income taxes	Income Taxes Income taxes are accounted for under the asset-and-liability method as required by FASB ASC Topic 740, Income Taxes FASB ASC Subtopic 740-10, Accounting for Uncertainty of Income Taxes
Net Loss Per Share	Net Loss Per Share Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during each period. The weighted-average number of shares of common stock outstanding used in the basic net loss per share calculation does not include unvested restricted stock awards as these instruments are considered contingently issuable shares until they vest. Diluted net loss per share of common stock includes the effect, if any, from the potential exercise of stock options, and the effect from unvested restricted stock awards and restricted stock units which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted-average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive. The Company’s unvested restricted stock awards entitles the holder to participate in dividends and earnings of the Company, and, if the Company were to recognize net income, it would have to use the two-class method to calculate earnings per share. The two-class method is not applicable during periods with a net loss, as the holders of the unvested restricted stock awards have no obligation to fund losses. The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: December 31, 2021 2020 Unvested restricted stock awards 611,608 1,214,767 Unvested restricted stock units 20,000 — Stock options 7,179,482 6,839,091 7,811,090 8,053,858 Amounts in the above table reflect the common stock equivalents.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Adopted Accounting Pronouncements On January 1, 2021, the Company adopted ASC 842 issued by the FASB in February 2016, which was subsequently supplemented by clarifying guidance to improve financial reporting of leasing transactions. The new lease accounting guidance requires lessees to recognize lease liabilities and right-of-use assets on the balance sheet for all leases with initial terms longer than 12 months and provides enhanced disclosures on key information of leasing arrangements. The Company adopted the new standard using the modified retrospective transition method utilizing the optional transition method and elected the package of practical expedients. Accordingly, prior periods were not restated to reflect the adopted standard. In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g., land, building, etc.), non-lease components (e.g., common area maintenance, maintenance, consumables, etc.), and non-components (e.g., property taxes, insurance, etc.). The Company has elected the practical expedient to account for the lease and non-lease components of each of its operating leases as a single lease component and allocate all of the contract consideration to the lease component only. Upon adoption, the Company recorded a right of use asset of $2.5 million and corresponding operating lease liabilities of $2.5 million, with an offset to accrued expenses and other current liabilities of approximately $64,000 to eliminate deferred rent on the balance sheets. At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term including any options to extend the lease that the Company is reasonably certain to exercise. The Company calculates the present value of lease payments using an incremental borrowing rate as the Company’s leases do not provide an implicit interest rate. The Company’s incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (“Short-Term Leases”). For Short-Term Leases, the Company records the rent expense on a straight-line basis and does not record the leases on the balance sheet. The Company entered into a short-term lease in June 2021 and elected the short-term lease exemption that allows the Company to record the rent expense on a straight-line basis and does not require the recognition of a right-of-use asset or corresponding operating lease liability. Refer to Note 8 for the Company’s lease disclosures. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement and (ii) the right-of-use lease asset based on the re-measured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received, and any initial direct costs incurred are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term. The adoption of the new lease accounting standard did not have a material impact on the Company’s results of operations or cash flows for the year ended December 31, 2021. Accounting guidance not yet adopted In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments ” which has subsequently been amended by ASU No. 2019-04, ASU No. 2019-05, ASU No. 2019-10, ASU No. 2019-11, and ASU No. 2020-03 (“ASU 2016-03”). This guidance replaces the incurred loss impairment methodology under current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This guidance is effective for the Company for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2022 and must be adopted using a modified retrospective approach, with certain exceptions. The Company is currently evaluating the impact of this standard on its financial statements and related disclosures. In November 2021, the FASB issued ASU No. 2021-10, “Government Assistance: Disclosures by Business Entities about Government Assistance” . The amendments in this Update improve financial reporting by requiring disclosures that increase the transparency of transactions with a government. The amendments require the following annual disclosures about transactions with a government that are accounted for by applying a grant or contribution accounting model by analogy (i) the type of transaction (ii) the accounting for the transaction, and (iii) the effect of the transaction on the entity’s financial statements. This guidance is effective for the Company for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021 with early adoption permitted. The Company is currently evaluating the impact of this standard but does not expect that it will have a material impact on its financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash and Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash and cash equivalents and restricted cash reported within the balance sheet that total to the amounts shown in the statement of cash flows: December 31, (in thousands) 2021 2020 Cash and cash equivalents $ 31,828 $ 218,309 Restricted cash 4,044 - Total cash, cash equivalents, and restricted cash shown in statement of cash flows $ 35,872 $ 218,309
Schedule of Property Plant and Equipment Useful Life	Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation expense is recognized using the straight-line method over the estimated useful life of the asset, ranging from 5-7 years as follows: Fixed Asset Type Estimated useful life Lab equipment 5 years Furniture and fixtures 7 years
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-average Shares of Common Stock Outstanding	The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares of common stock outstanding, as they would be anti-dilutive: December 31, 2021 2020 Unvested restricted stock awards 611,608 1,214,767 Unvested restricted stock units 20,000 — Stock options 7,179,482 6,839,091 7,811,090 8,053,858

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Schedule of Marketable Securities	The following is a summary of the Company’s marketable securities as of December 31, 2021. The Company did not have any marketable securities as of December 31, 2020. (in thousands) Amortized Cost Gross unrealized gain Gross unrealized loss Fair Value Marketable securities Corporate debt securities $ 193,798 $ 1 $ (696 ) $ 193,103 Commercial paper 66,318 1 (17 ) 66,302 $ 260,116 $ 2 $ (713 ) $ 259,405

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following fair value hierarchy table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis: Fair value measurement at reporting date using (in thousands) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) December 31, 2021: Assets: Cash equivalents (Money Market Funds) $ 30,520 $ — $ — Marketable securities Corporate debt securities — 193,103 — Commercial paper — 66,302 — Total 30,520 259,405 — December 31, 2020: Assets: Cash equivalents (Money Market Funds) $ 217,072 $ — $ —

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following: December 31, (in thousands) 2021 2020 Lab equipment $ 4,266 $ 3,010 Leasehold improvements 875 448 Furniture and fixtures 118 105 Construction in progress 668 — 5,927 3,563 Less accumulated depreciation (1,998 ) (1,083 ) Property and equipment, net $ 3,929 $ 2,480

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: December 31, (in thousands) 2021 2020 Compensation and related benefits $ 4,919 $ 3,614 Research and development 4,615 3,421 Other 87 420 $ 9,621 $ 7,455

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2021
Operating Lease Expiring December 2022
Schedule of Future Minimum Lease Payments Under Lease	The future minimum lease payments under the Lease at December 31, 2021 are as follows: (in thousands) 2022 $ 1,836 Total undiscounted lease payments 1,836 Less imputed interest (96 ) Current lease liability $ 1,740
Chestnut Run Lease
Schedule of Future Minimum Lease Payments Under Lease	The estimated rent payments due over the next five years is as follows: (in thousands) 2022 $ - 2023 840 2024 2,141 2025 2,350 2026 2,409 Thereafter 26,098

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 Recorded in Statements of Operations	The Company recorded stock-based compensation expense in the following expense categories in its accompanying statements of operations: Year Ended December 31, (in thousands) 2021 2020 Research and development $ 9,469 $ 2,585 General and administrative 11,462 2,998 $ 20,931 $ 5,583
Summary of Stock Option Activity	The following table summarizes stock option activity for the Plan in the years indicated: Number of shares Weighted average exercise price per share Weighted average remaining contractual term (years) Outstanding at January 1, 2020 2,269,742 $ 1.66 9.20 Granted 4,785,630 $ 11.35 Exercised (100,545 ) $ 0.99 Forfeited (115,736 ) $ 1.37 Outstanding at December 31, 2020 6,839,091 $ 8.46 9.17 Granted 2,600,231 $ 31.14 Exercised (995,950 ) $ 3.52 Forfeited (1,263,890 ) $ 19.79 Outstanding at December 31, 2021 7,179,482 $ 15.36 8.66 Exercisable at December 31, 2021 2,057,975 $ 6.99 8.04
Summary of Information about Stock Options Outstanding	The following table summarizes information about stock options outstanding and exercisable at December 31, 2021 under the Plan: Options Outstanding Options Exercisable Range of Exercise Prices Number Outstanding Weighted Average Remaining Contractual Life (in years) Weighted Average Exercise Price Number Exercisable Weighted Average Exercise Price $0.31 - $7.37 2,352,647 7.76 $ 1.80 1,233,638 $ 1.75 $7.38 - $13.08 2,465,488 8.67 12.85 777,587 12.85 $13.09 - $31.30 1,760,632 9.61 27.58 4,219 17.99 $31.31 - $88.98 600,715 9.35 43.02 42,531 50.79 7,179,482 2,057,975
Schedule of Fair Value of Each Option Estimated on Date of Grant Using Weighted Average Assumptions	The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below: Year Ended December 31, 2021 2020 Expected volatility 87.46 % 115.17 % Risk-free interest rate 0.94 % 0.43 % Expected life (in years) 6.04 6.25 Expected dividend yield — —
Summary of Activity related to RSA Stock-Based Payment Awards	The following table summarizes activity related to RSA stock-based payment awards: Number of shares Weighted- average grant date fair value Unvested balance at January 1, 2020 1,335,349 $ 1.42 Granted 432,301 $ 3.26 Vested (552,883 ) $ 1.37 Unvested balance at December 31, 2020 1,214,767 $ 2.09 Vested (603,159 ) $ 1.89 Unvested balance at December 31, 2021 611,608 $ 2.29
Summary of Activity related to RSU Stock-Based Payment Awards	The following table summarizes activity related to RSU stock-based payment awards: Number of shares Weighted- average grant date fair value Outstanding at January 1, 2021 — Granted 45,000 $ 26.91 Forfeited (25,000 ) $ 33.78 Outstanding at December 31, 2021 20,000 $ 18.32

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities were as follows: December 31, (in thousands) 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 60,495 $ 28,283 Research and development credits 11,240 4,753 Stock-based compensation 2,448 33 Accrued expense 1,290 — Lease liabilities 485 — Gross deferred tax assets 75,958 33,069 Less: valuation allowance (75,371 ) (32,899 ) Total deferred tax asset 587 170 Deferred tax liability Right-of-use assets (476 ) — Depreciation (111 ) (170 ) Total deferred tax liabilities (587 ) (170 ) Net deferred tax assets $ — $ —
Schedule of Reconciliation of the Federal Income tax Rate to Effective Tax Rate	A reconciliation of the federal income tax rate to the Company’s effective tax rate is as follows: Year ended December 31, 2021 2020 Federal tax benefit at statutory rate (21.0 )% (21.0 )% State tax, net of federal benefit (7.7 ) (6.5 ) Permanent differences (3.5 ) 1.2 Research and development (5.8 ) (4.4 ) Change in valuation allowance 38.0 30.7 — % — %
Schedule of Federal and State Net Operating Losses and Research Tax Credits	The following table summarizes carryforwards of federal and state net operating losses (“NOL”) and research tax credits: December 31, (in thousands) 2021 2020 NOL carryforwards - Federal $ 217,038 $ 101,471 NOL carryforwards - State 217,038 101,471 Research tax credits - Federal 11,206 4,720 Research tax credits - State 43 43

Risks and Liquidity - Additiona

Risks and Liquidity - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Risks And Liquidity [Abstract]
Accumulated deficit	$ (219,120)	$ (107,426)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 31,828	$ 218,309
Restricted cash	4,044
Total cash, cash equivalents, and restricted cash shown in statement of cash flows	$ 35,872	$ 218,309

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 01, 2021
Summary of Significant Accounting Policies [Line Items]
Depreciation expense description	Depreciation expense is recognized using the straight-line method over the estimated useful life of the asset, ranging from 5-7 years
Right-of-use asset	$ 1,707,000
Offset accrued expense and other current liabilities to eliminate deferred rent	$ 64,000
ASU 2016-02
Summary of Significant Accounting Policies [Line Items]
Change in accounting principle, ASU, adopted	true
Change in accounting principle, ASU, adoption date	Jan. 1, 2021
Change in accounting principle, ASU, immaterial effect	true
Right-of-use asset		$ 2,500,000
Operating lease liability		$ 2,500,000
Minimum
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Maximum
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	7 years
Percentage of tax benefit recognized upon settlement	50.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Property Plant and Equipment Useful Life (Details)	12 Months Ended
	Dec. 31, 2021
Lab equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	7 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-average Shares of Common Stock Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	7,811,090	8,053,858
Unvested Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	611,608	1,214,767
Unvested Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	20,000
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	7,179,482	6,839,091

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Marketable Securities [Line Items]
Marketable securities, Amortized cost	$ 260,116
Marketable securities, Gross unrealized gain	2
Marketable securities, Gross unrealized loss	(713)
Marketable securities, Fair value	259,405
Corporate Debt Securities
Marketable Securities [Line Items]
Marketable securities, Amortized cost	193,798
Marketable securities, Gross unrealized gain	1
Marketable securities, Gross unrealized loss	(696)
Marketable securities, Fair value	193,103
Commercial Paper
Marketable Securities [Line Items]
Marketable securities, Amortized cost	66,318
Marketable securities, Gross unrealized gain	1
Marketable securities, Gross unrealized loss	(17)
Marketable securities, Fair value	$ 66,302

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) $ in Millions	Dec. 31, 2021USD ($)Security
Investments Debt And Equity Securities [Abstract]
Number of marketable securities | Security	25
Securities fair market value unrealized loss position | $	$ 221.8

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value measurement, recurring basis, assets	$ 30,520
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value measurement, recurring basis, assets	30,520	$ 217,072
Significant other observable inputs (Level 2)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value measurement, recurring basis, assets	259,405
Significant other observable inputs (Level 2) | Corporate Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value measurement, recurring basis, assets	193,103
Significant other observable inputs (Level 2) | Commercial Paper
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value measurement, recurring basis, assets	$ 66,302

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 5,927	$ 3,563
Less accumulated depreciation	(1,998)	(1,083)
Property and equipment, net	3,929	2,480
Lab equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,266	3,010
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	875	448
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	118	$ 105
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 668

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - Lab equipment - USD ($)	1 Months Ended
	Sep. 30, 2019	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Lease term	12 months
Capital lease	$ 400,000
Effective interest percentage	9.67%
Accumulated amortization related to the capital lease		$ 100,000
Lease payments under capital lease		$ 0

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
Payables And Accruals [Abstract]
Compensation and related benefits	$ 4,919	$ 3,614
Research and development	4,615	3,421
Other	87	420
Accrued expenses and other current liabilities	$ 9,621	$ 7,455

Commitments - Additional Inform

Commitments - Additional Information (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)Instalment	Dec. 31, 2021USD ($)ft²Extension	Dec. 31, 2021USD ($)ft²	Dec. 31, 2020USD ($)
Other Commitments [Line Items]
Lessee, operating lease, option to extend			This option to extend was not recognized as part of the Company’s measurement of the right-of-use asset and operating lease liability as of December 31, 2021
Operating lease estimated incremental borrowing rate percent			10.00%
Non cancellable lease period			12 months
Lease commencement date			Jul. 1, 2021
Lease expiration date			Jun. 30, 2022
Rent expense			$ 1,800,000	$ 1,200,000
Defined contribution plan, maximum annual contributions per employee, percent			100.00%
Defined contribution plan, employer matching contribution, percent of employee's gross pay			3.00%
Defined contribution plan, employer discretionary contribution amount			$ 500,000	0
Research and development			86,778,000	$ 48,177,000
DarwinHealth
Other Commitments [Line Items]
Estimated years of research collaboration agreement	1 year
Estimated amount of payment over a agreement term	$ 3,000,000
Number of equal instalments | Instalment	3
Research term	1 year
Research and development			$ 1,000,000
Grace period following research term for potential refund	18 months
Potential refund receivable from agreement	$ 500,000
DarwinHealth | Maximum
Other Commitments [Line Items]
Agreement is eligible to receive payment in future research, development and regulatory milestones	$ 3,000,000
Operating Lease Expiring December 2022
Other Commitments [Line Items]
Lease renewal period		1 year	1 year
Operating lease payments due in 2022		$ 1,836,000	$ 1,836,000
Chestnut Run Lease
Other Commitments [Line Items]
Lease renewal period		5 years	5 years
Area of lease premises | ft²		81,000	81,000
Initial term of lease		162 months
Number of lease extensions | Extension		3
Aggregate estimated rent payments due over initial term		$ 33,800,000	$ 33,800,000
Chestnut Run Lease | Letter of Credit
Other Commitments [Line Items]
Security deposit		4,000,000	4,000,000
Chestnut Run Lease | Letter of Credit | Pro Forma
Other Commitments [Line Items]
Security deposit		500,000	500,000
Short-Term Lease
Other Commitments [Line Items]
Operating lease payments due in 2022		$ 200,000	$ 200,000

Commitments - Schedule of Futur

Commitments - Schedule of Future Minimum Lease Payments Under Lease (Details) $ in Thousands	Dec. 31, 2021USD ($)
Lease Liability [Line Items]
Operating lease liability	$ 1,740
Operating Lease Expiring December 2022
Lease Liability [Line Items]
2022	1,836
Total undiscounted lease payments	1,836
Less imputed interest	(96)
Operating lease liability	1,740
Chestnut Run Lease
Lease Liability [Line Items]
2023	840
2024	2,141
2025	2,350
2026	2,409
Thereafter	$ 26,098

Convertible Preferred Stock a_2

Convertible Preferred Stock and Common Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended					12 Months Ended
	Jan. 31, 2021	Sep. 30, 2020	Aug. 31, 2020	Mar. 31, 2020	May 31, 2019	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Proceeds from the issuance of common stock upon initial public offering, net of offering costs							$ 166,630
Proceeds from the sale of common stock, net of offering costs						$ 161,424
Common Stock
Class Of Stock [Line Items]
Common stock, voting rights						The holders of the voting common stock are entitled to one vote for each share of voting common stock held at all meetings of stockholders
Common Stock | Minimum
Class Of Stock [Line Items]
Beneficial ownership percentage		9.99%
Common Stock | Maximum
Class Of Stock [Line Items]
Beneficial ownership percentage		19.99%
IPO
Class Of Stock [Line Items]
Sale of common stock in initial public offering		9,573,750
Proceeds from the issuance of common stock upon initial public offering, net of offering costs		$ 166,600
Convertible preferred stock converted into common stock		30,437,423
Common stock, shares authorized		500,000,000
IPO | Common Stock
Class Of Stock [Line Items]
Public offering price		$ 19
Series B Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares issued				7,628,846	7,628,846
Convertible preferred stock, price per share					$ 3.9325
Net proceeds from issuance of preferred stock				$ 29,900	$ 29,800		29,942
Additional shares issuable					7,628,846
Series C Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares issued			3,443,612
Convertible preferred stock, price per share			$ 14.5197
Net proceeds from issuance of preferred stock			$ 49,800				$ 49,826
Non-voting Common Stock
Class Of Stock [Line Items]
Common stock, shares authorized						12,850,259	12,850,259
Non-voting Common Stock | Common Stock
Class Of Stock [Line Items]
Sale of common stock in initial public offering						291,666
Non-voting Common Stock | IPO
Class Of Stock [Line Items]
Convertible preferred stock converted into common stock		11,110,371
Common Stock | Follow-on Offering
Class Of Stock [Line Items]
Public offering price	$ 60
Number of shares sold	2,875,000
Proceeds from the sale of common stock, net of offering costs	$ 161,400

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021USD ($)Plan$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Jan. 01, 2022shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of equity incentive plans | Plan	2
Aggregate intrinsic value of outstanding options	$ 25,100,000
Aggregate intrinsic value of exercisable options	13,200,000
Stock-based compensation expense	$ 20,931,000	$ 5,583,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant date fair value of options granted | $ / shares	$ 22.80	$ 10.12
Aggregate intrinsic value of options exercised	$ 26,900,000
Stock-based compensation expense	19,900,000	$ 4,800,000
Total unrecognized compensation expense related to unvested stock option awards	$ 68,400,000
Total unrecognized compensation expense, weighted-average period	3 years 10 days
Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years
Stock-based compensation expense	$ 900,000	$ 800,000
Total unrecognized compensation expense, weighted-average period	1 year 9 months 29 days
Share-based payment arrangement, nonvested award, unrecognized expense	$ 1,300,000
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years
Stock-based compensation expense	$ 20,000
Total unrecognized compensation expense, weighted-average period	3 years 9 months 3 days
Share-based payment arrangement, nonvested award, unrecognized expense	$ 300,000
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized | shares		4,680,000
Number of shares available for future grants | shares	5,314,849
Terms of award	The total number of shares initially authorized under the Plan was 4,680,000, which was increased on January 1, 2021 and will automatically increase on January 1st of each year, continuing for ten years, in an amount equal to five percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year.
Award term	10 years
Percentage of shares outstanding used to calculate annual increase in number of shares that can be issued	5.00%
Award vesting period	4 years
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future grants | shares	931,342
Terms of award	The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the ESPP shall automatically increase on January 1st of each year and continuing for ten years beginning in 2021, in an amount equal to one percent of the total number of shares of all classes of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year.
Award term	10 years
Percentage of shares outstanding used to calculate annual increase in number of shares that can be issued	1.00%
Stock-based compensation expense	$ 200,000
Shares issued | shares	25,714
Eligible employees purchase common stock percentage of lower of fair market value	85.00%
Participants accrue rights to purchase maximum common stock amount	$ 25,000
2020 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Eligible employees contribution percentage	15.00%
Vesting After One Year | Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stock options vested	25.00%
Vesting After One Year | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stock options vested	25.00%
Vesting After One Year | 2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of stock options vested	25.00%
Subsequent Event | 2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized | shares			2,380,116
Subsequent Event | 2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized | shares			476,023

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense Recorded in Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 20,931	$ 5,583
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	9,469	2,585
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 11,462	$ 2,998

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of shares, Outstanding at beginning of period	6,839,091	2,269,742
Number of shares, Granted	2,600,231	4,785,630
Number of shares, Exercised	(995,950)	(100,545)
Number of shares, Forfeited	(1,263,890)	(115,736)
Number of shares, Outstanding at end of period	7,179,482	6,839,091	2,269,742
Number of shares, Exercisable at December 31, 2021	2,057,975
Weighted average exercise price per share, Outstanding at beginning of period	$ 8.46	$ 1.66
Weighted average exercise price per share, Granted	31.14	11.35
Weighted average exercise price per share, Exercised	3.52	0.99
Weighted average exercise price per share, Forfeited	19.79	1.37
Weighted average exercise price per share, Outstanding at end of period	15.36	$ 8.46	$ 1.66
Weighted average exercise price per share, Exercisable at December 31, 2021	$ 6.99
Weighted average remaining contractual term (years), Outstanding	8 years 7 months 28 days	9 years 2 months 1 day	9 years 2 months 12 days
Weighted average remaining contractual term (years), Exercisable	8 years 14 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Information about Stock Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Number | shares	7,179,482
Options Exercisable, Number Exercisable | shares	2,057,975
$0.31 - $7.37
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Range of Exercise Prices, Minimum	$ 0.31
Range of Exercise Prices, Maximum	$ 7.37
Options Outstanding, Number | shares	2,352,647
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	7 years 9 months 3 days
Options Outstanding, Weighted Average Exercise Price	$ 1.80
Options Exercisable, Number Exercisable | shares	1,233,638
Options Exercisable, Weighted Average Exercise Price	$ 1.75
$7.38 - $13.08
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Range of Exercise Prices, Minimum	7.38
Range of Exercise Prices, Maximum	$ 13.08
Options Outstanding, Number | shares	2,465,488
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	8 years 8 months 1 day
Options Outstanding, Weighted Average Exercise Price	$ 12.85
Options Exercisable, Number Exercisable | shares	777,587
Options Exercisable, Weighted Average Exercise Price	$ 12.85
$13.09 - $31.30
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Range of Exercise Prices, Minimum	13.09
Range of Exercise Prices, Maximum	$ 31.30
Options Outstanding, Number | shares	1,760,632
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 7 months 9 days
Options Outstanding, Weighted Average Exercise Price	$ 27.58
Options Exercisable, Number Exercisable | shares	4,219
Options Exercisable, Weighted Average Exercise Price	$ 17.99
$31.31 - $88.98
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Range of Exercise Prices, Minimum	31.31
Range of Exercise Prices, Maximum	$ 88.98
Options Outstanding, Number | shares	600,715
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 4 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 43.02
Options Exercisable, Number Exercisable | shares	42,531
Options Exercisable, Weighted Average Exercise Price	$ 50.79

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Fair Value of Each Option Estimated on Date of Grant Using Weighted Average Assumptions (Details) - Stock Options	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	87.46%	115.17%
Risk-free interest rate	0.94%	0.43%
Expected life (in years)	6 years 14 days	6 years 3 months

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Activity related to RSA Stock-Based Payment Awards (Details) - Restricted Stock Awards - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Unvested balance at beginning of period	1,214,767	1,335,349
Number of shares, Granted		432,301
Number of shares, Vested	(603,159)	(552,883)
Number of shares, Unvested balance at end of period	611,608	1,214,767
Weighted-average grant date fair value, Unvested balance at beginning of period	$ 2.09	$ 1.42
Weighted-average grant date fair value, Granted		3.26
Weighted-average grant date fair value, Vested	1.89	1.37
Weighted-average grant date fair value, Unvested balance at end of period	$ 2.29	$ 2.09

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Activity related to RSU Stock-Based Payment Awards (Details) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Granted | shares	45,000
Number of shares, Forfeited | shares	(25,000)
Number of shares, Unvested balance at end of period | shares	20,000
Weighted-average grant date fair value, Granted | $ / shares	$ 26.91
Weighted-average grant date fair value, Forfeited | $ / shares	33.78
Weighted-average grant date fair value, Unvested balance at end of period | $ / shares	$ 18.32

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 60,495	$ 28,283
Research and development credits	11,240	4,753
Stock-based compensation	2,448	33
Accrued expense	1,290
Lease liabilities	485
Gross deferred tax assets	75,958	33,069
Less: valuation allowance	(75,371)	(32,899)
Total deferred tax asset	587	170
Deferred tax liability
Right-of-use assets	(476)
Depreciation	(111)	(170)
Total deferred tax liabilities	(587)	(170)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Deferred tax assets, valuation allowance increase	$ 42,500,000	$ 17,500,000
Research and development tax credits	$ 11,240,000	$ 4,753,000
NOL and tax credit carryforwards	The NOL and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. NOL 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 Internal Revenue Code, respectively, as well as similar state provisions.
Accrued interest related to uncertain tax positions	$ 0
Accrued penalties related to uncertain tax positions	0
Interest related to uncertain tax positions	0
Penalties related to uncertain tax positions	0
Internal Revenue Service (IRS)
Income Tax Disclosure [Line Items]
Research and development tax credits	$ 11,200,000
Tax credits expiration year	2036
Delaware
Income Tax Disclosure [Line Items]
Research and development tax credits	$ 43,000
Tax credits expiration year	2031

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of the Federal Income tax Rate to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal tax benefit at statutory rate	(21.00%)	(21.00%)
State tax, net of federal benefit	(7.70%)	(6.50%)
Permanent differences	(3.50%)	1.20%
Research and development	(5.80%)	(4.40%)
Change in valuation allowance	38.00%	30.70%
Effective tax rate	0.00%	0.00%

Income Taxes - Schedule of Fede

Income Taxes - Schedule of Federal and State Net Operating Losses and Research Tax Credits (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
NOL carryforwards	$ 60,495	$ 28,283
Federal
Operating Loss Carryforwards [Line Items]
NOL carryforwards	217,038	101,471
Research tax credits	11,206	4,720
State
Operating Loss Carryforwards [Line Items]
NOL carryforwards	217,038	101,471
Research tax credits	$ 43	$ 43