Morphic Holding (MORF) 10-K 22 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 20, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38940
Entity Registrant Name	MORPHIC HOLDING, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3878772
Entity Address, Address Line One	35 Gatehouse Drive
Entity Address, Address Line Two	A2
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	781
Local Phone Number	996-0955
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	MORF
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 2,140,323,306
Entity Common Stock, Shares Outstanding		50,037,229
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive proxy statement to be filed for its 2024 Annual Meeting of Stockholders are incorporated by reference into Part III hereof. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the end of the fiscal year covered by this Annual Report on Form 10-K.
Entity Central Index Key	0001679363
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 58,577	$ 59,272
Marketable securities	645,772	288,976
Accounts receivable	0	455
Prepaid expenses and other current assets	12,579	13,479
Total current assets	716,928	362,182
Operating lease right-of-use assets	2,133	3,514
Property and equipment, net	2,767	2,119
Restricted cash	560	560
Other assets	126	214
Total assets	722,514	368,589
Current liabilities:
Accounts payable	7,698	3,475
Accrued and other current expenses	17,078	13,181
Deferred revenue, current portion	0	470
Total current liabilities	24,776	17,126
Long-term liabilities:
Operating lease liability, net of current portion	716	2,344
Total liabilities	25,492	19,470
Commitments and contingencies (Note 11)
Stockholders’ Equity
Preferred shares, $0.0001 par value, 10,000,000 shares authorized, no shares issued and outstanding as of December 31, 2023 and December 31, 2022	0	0
Common shares, $0.0001 par value, 400,000,000 shares authorized, 49,747,286 shares issued and outstanding as of December 31, 2023 and 38,584,678 shares issued and outstanding as of December 31, 2022	5	4
Additional paid‑in capital	1,143,919	649,549
Accumulated deficit	(449,190)	(297,095)
Accumulated other comprehensive income (loss)	2,288	(3,339)
Total stockholders’ equity	697,022	349,119
Total liabilities and stockholders’ equity	$ 722,514	$ 368,589

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred shares, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred shares, shares authorized (in shares)	10,000,000	10,000,000
Preferred shares, shares issued (in shares)	0	0
Preferred shares, shares outstanding (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common shares, shares issued (in shares)	49,747,286	38,584,678
Common shares, shares outstanding (in shares)	49,747,286	38,584,678

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Collaboration revenue	$ 521	$ 70,808	$ 19,794
Operating expenses:
Research and development	140,384	102,062	87,789
General and administrative	38,823	32,142	27,811
Total operating expenses	179,207	134,204	115,600
Loss from operations	(178,686)	(63,396)	(95,806)
Other income:
Interest income, net	26,969	4,567	272
Other income (expense), net	2	(145)	(8)
Total other income, net	26,971	4,422	264
Loss before provision for income taxes	(151,715)	(58,974)	(95,542)
Provision for income taxes	(380)	(67)	0
Net loss	$ (152,095)	$ (59,041)	$ (95,542)
Net loss per share, basic (in dollars per share)	$ (3.59)	$ (1.55)	$ (2.67)
Net loss per share, diluted (in dollars per share)	$ (3.59)	$ (1.55)	$ (2.67)
Weighted average common shares outstanding, basic (in shares)	42,390,554	38,112,498	35,797,969
Weighted average common shares outstanding, diluted (in shares)	42,390,554	38,112,498	35,797,969
Comprehensive loss:
Net loss	$ (152,095)	$ (59,041)	$ (95,542)
Other comprehensive income (loss):
Unrealized holding losses on marketable securities, net of tax	5,627	(2,857)	(461)
Total other comprehensive income (loss)	5,627	(2,857)	(461)
Comprehensive loss	$ (146,468)	$ (61,898)	$ (96,003)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	At-The-Market Offering	Secondary Offering	Private Placement	Common Shares	Common Shares At-The-Market Offering	Common Shares Secondary Offering	Common Shares Private Placement	Additional Paid‑in Capital	Additional Paid‑in Capital At-The-Market Offering	Additional Paid‑in Capital Secondary Offering	Additional Paid‑in Capital Private Placement	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period ( in shares) at Dec. 31, 2020					32,037,686
Balance at beginning of period at Dec. 31, 2020	$ 145,197				$ 3				$ 287,727				$ (142,512)	$ (21)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity‑based compensation expense	21,184								21,184
Vesting of restricted shares (in shares)					127,335
Issuance of common shares upon stock option exercises (in shares)					827,830
Issuance of common shares upon stock option exercises	9,536								9,536
Issuance of common shares under the Employee Stock Purchase Plan (in shares)					35,563
Issuance of common shares under the Employee Stock Purchase Plan	1,095								1,095
Issuance of common shares, net of issuance/offering costs (in shares)						556,983	3,500,000
Issuance of common shares, net of issuance/offering costs		$ 25,708	$ 229,982				$ 1			$ 25,708	$ 229,981
Issuance of pre-funded warrants to purchase common shares through private placement, net of issuance costs	0
Unrealized holding losses on marketable securities, net of tax	(461)													(461)
Net loss	(95,542)												(95,542)
Balance at end of period ( in shares) at Dec. 31, 2021					37,085,397
Balance at end of period at Dec. 31, 2021	336,699				$ 4				575,231				(238,054)	(482)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity‑based compensation expense	29,048								29,048
Vesting of restricted shares (in shares)					9,171
Issuance of common shares upon stock option exercises (in shares)					459,839
Issuance of common shares upon stock option exercises	5,175								5,175
Issuance of common shares under the Employee Stock Purchase Plan (in shares)					30,271
Issuance of common shares under the Employee Stock Purchase Plan	885								885
Issuance of common shares, net of issuance/offering costs (in shares)							1,000,000
Issuance of common shares, net of issuance/offering costs			39,210								39,210
Issuance of pre-funded warrants to purchase common shares through private placement, net of issuance costs	4
Unrealized holding losses on marketable securities, net of tax	(2,857)													(2,857)
Net loss	$ (59,041)												(59,041)
Balance at end of period ( in shares) at Dec. 31, 2022	38,584,678				38,584,678
Balance at end of period at Dec. 31, 2022	$ 349,119				$ 4				649,549				(297,095)	(3,339)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity‑based compensation expense	40,943								40,943
Vesting of restricted shares (in shares)					62,085
Issuance of common shares upon stock option exercises (in shares)					584,959
Issuance of common shares upon stock option exercises	9,027								9,027
Issuance of common shares under the Employee Stock Purchase Plan (in shares)					34,628
Issuance of common shares under the Employee Stock Purchase Plan	993								993
Issuance of common shares, net of issuance/offering costs (in shares)						1,518,759	6,133,334	848,655
Issuance of common shares, net of issuance/offering costs		$ 84,548	$ 259,061	$ 29,940			$ 1			$ 84,548	$ 259,060	$ 29,940
Issuance of common stock upon exercise of pre-funded warrants (in shares)					1,980,188
Issuance of pre-funded warrants to purchase common shares through private placement, net of issuance costs	0			$ 69,859								$ 69,859
Unrealized holding losses on marketable securities, net of tax	5,627													5,627
Net loss	$ (152,095)												(152,095)
Balance at end of period ( in shares) at Dec. 31, 2023	49,747,286				49,747,286
Balance at end of period at Dec. 31, 2023	$ 697,022				$ 5				$ 1,143,919				$ (449,190)	$ 2,288

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2021
At-The-Market Offering
Offering costs	$ 1.8	$ 1.2
Private Placement
Offering costs	0.1
Secondary Offering
Offering costs	$ 16.9	$ 15

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (152,095)	$ (59,041)	$ (95,542)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,091	1,005	1,030
Discount accretion and premium amortization on marketable securities	(10,595)	800	1,215
Equity‑based compensation	40,943	29,048	21,184
Loss on sale of marketable securities	0	154	0
Loss on disposal of equipment	0	0	4
Change in operating assets and liabilities:
Accounts receivable	455	1,852	5,007
Prepaid expenses and other current assets	896	(5,529)	(4,035)
Other assets	88	(207)	59
Operating lease right-of-use assets	1,381	1,292	1,098
Accounts payable	3,725	(1,553)	970
Accrued expenses	3,763	60	1,467
Deferred revenue	(470)	(67,647)	(14,821)
Operating lease liabilities	(1,494)	(1,211)	(1,097)
Net cash used in operating activities	(112,312)	(100,977)	(83,461)
Cash flows from investing activities:
Purchases of marketable securities	(764,029)	(238,274)	(244,160)
Proceeds from maturities of marketable securities	423,455	175,042	132,000
Proceeds from sale of marketable securities	0	7,146	0
Purchase of property and equipment	(1,241)	(365)	(1,020)
Net cash used in investing activities	(341,815)	(56,451)	(113,180)
Cash flows from financing activities:
Proceeds from issuance of common shares and pre-funded warrants through the private placement	99,799	0	0
Proceeds from issuance of common shares under Employee Stock Purchase Plan	993	885	1,095
Proceeds from issuance of common shares upon stock option exercises	9,031	5,171	9,536
Net cash provided by financing activities	453,432	45,266	266,313
Net (decrease) increase in cash, cash equivalents and restricted cash	(695)	(112,162)	69,672
Cash, cash equivalents and restricted cash, beginning of period	59,832	171,994	102,322
Cash, cash equivalents and restricted cash, end of period	59,137	59,832	171,994
Non-cash activities:
Purchases of property and equipment included in accounts payable and accrued expenses	674	176	0
Amounts from exercise of stock options included in prepaid expenses and other current assets	0	4	0
Right-of-use assets obtained in exchange for operating lease liabilities	0	0	4,434
Supplemental cash flow information:
Cash paid for taxes	335	50	170
At-The-Market Offering
Cash flows from financing activities:
Proceeds from issuance of common shares, net	84,548	39,210	25,700
Secondary Offering
Cash flows from financing activities:
Proceeds from issuance of common shares, net	$ 259,061	$ 0	$ 229,982

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	Nature of the Business Organization and Liquidity Morphic Holding, Inc. (the “Company”) was formed under the laws of the State of Delaware in August 2014. The Company is a biopharmaceutical company applying proprietary insights into integrin medicine to discover and develop potentially first-in-class oral small molecule integrin therapeutics. Integrins are a validated target class with multiple approved drugs for the treatment of serious chronic diseases. Despite significant biopharmaceutical industry investment, to the Company's knowledge no oral small molecule integrin therapies have been approved by the U.S. Food and Drug Administration or any European regulatory authority. The Company has created the Morphic integrin technology platform, or MInT Platform, by leveraging its unique understanding of integrin structure and biology, to develop a pipeline of novel product candidates designed to achieve potency, high selectivity and the pharmaceutical properties required for oral administration. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The Company expects to continue to incur losses from operations for the foreseeable future. The Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next 12 months from the date these financial statements were issued. In July 2020, the Company entered into an Open Market Sale Agreement (the “Original Agreement”) with Jefferies LLC (“Jefferies”) with respect to an at-the-market offering program under which the Company could offer and sell, from time to time at its sole discretion, shares of its common stock, having an aggregate offering amount of up to $75.0 million, referred to as Placement Shares, through Jefferies as its sales agent. The Company paid Jefferies a commission on the gross sales proceeds of any Placement Shares sold through Jefferies under the Original Agreement, and also provided Jefferies with customary indemnification and contribution rights. On August 11, 2021, the Company entered into an Amendment No. 1 to the Original Agreement with Jefferies, establishing a new at-the-market offering (“New ATM”) with an aggregate offering amount of up to $150.0 million, also subject to a commission on the gross proceeds from sales of Placement Shares, sold through Jefferies. Under the New ATM, the Company may offer and sell, from time to time at its sole discretion, Placement Shares through Jefferies as its sales agent. During the year ended December 31, 2023, the Company issued and sold 1,518,759 shares under the New ATM for net proceeds of approximately $84.5 million after deducting offering commissions and expenses. As of December 31, 2023, the Company had approximately $10.9 million of common stock remaining available for sale under the New ATM. In March 2021, the Company completed an underwritten follow-on public offering of 3,500,000 shares of its common stock at a price to the public of $70.00 per share. Gross proceeds from the secondary offering were approximately $245.0 million, before deducting underwriting discounts, commissions and other offering expenses of approximately $15.0 million, paid by the Company, resulting in net proceeds of approximately $230.0 million. In February 2023, the Company entered into a securities purchase agreement with existing investors, consisting of a board member and holder of more than 5% of the Company’s common stock and a holder of more than 5% of the Company’s common stock, pursuant to which the Company sold to the investors, in a private placement, 848,655 shares of common stock at a price of $35.35 per share (the “PIPE Shares”) and pre-funded warrants to purchase up to 1,980,198 shares of common stock at a purchase price of $35.3499 per pre-funded warrant where each pre-funded warrant has an exercise price of $0.0001 per share (the “Pre-Funded Warrants”). The Company received aggregate gross proceeds of approximately $100.0 million, before deducting costs and offering expenses payable by the Company, resulting in net proceeds of approximately $99.8 million. In May 2023, the Company completed an underwritten public offering of 6,133,334 shares of its common stock, which includes 800,000 shares sold upon the exercise in full of the underwriters’ option to purchase additional shares of common stock, at a price to the public of $45.00 per share. Gross proceeds from the secondary offering were approximately $276.0 million, before deducting underwriting discounts, commissions and other offering expenses payable by the Company of approximately $16.9 million, resulting in net proceeds of approximately $259.1 million.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of Morphic Holding, Inc. and its wholly-owned subsidiaries, Morphic Therapeutic, Inc., Morphic Therapeutic UK Ltd and Morphic Security Corporation. All intercompany balances have been eliminated in consolidation. These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Use of Estimates and Summary of Significant Accounting Policies The preparation of financial statements in accordance with GAAP requires management to make estimates and judgments that may affect the reported amounts of assets and liabilities and related disclosures of contingent assets and liabilities at the date of the financial statements and the related reporting of revenues and expenses during the reporting period. Significant estimates of accounting reflected in these consolidated financial statements include, but are not limited to, estimates related to revenue recognition and accrued research and development expenses. Actual results for accrued research and development expenses could differ from those estimates. On March 2, 2022, the Company incorporated Morphic Therapeutic UK Ltd in London, U.K., to support Company functions outside of the United States. The geographic location of all long-lived assets of the Company continues to be the United States. The functional reporting currency of Morphic Therapeutic UK Ltd is the United States Dollar. Foreign currency remeasurement is included in other income (expense) in the Company’s consolidated statements of operations. Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, and accounts receivable. The Company’s cash and cash equivalents are held at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The primary objectives for the Company’s investment portfolio are the preservation of capital and maintenance of liquidity. The Company’s investment policy allows funds to be held outside bank accounts, but to be invested only in readily marketable fixed income instruments with readily ascertainable market values, denominated and payable in United States Dollars including obligations of the U.S. government, U.S. government-sponsored enterprises, U.S. government agencies and highly rated corporate debt obligations, including commercial paper and corporate bonds, and money market funds registered according to Rule 2a-7 of the Investment Company Act of 1940. Investments in the money market fund shall be consistent with approved instruments and assets under management must be at least $1.0 billion. The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign-hedging arrangements. Cash and Cash Equivalents and Restricted Cash The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. At December 31, 2023, cash and cash equivalents include bank demand deposits and money market funds that invest primarily in U.S. government securities. At December 31, 2022, cash and cash equivalents include bank demand deposits, money market funds that invest primarily in U.S. government securities, and U.S. Treasury securities. Cash equivalents are stated at cost, which approximates fair value. Restricted cash consists of cash collateralizing a letter of credit in the amount of $560,000 issued to the landlord of the Company’s facility lease as of December 31, 2023 and 2022. The letter of credit and cash collateralizing it increased to $560,000 in August 2021 due to the operating lease extension. The terms of the letter of credit extend beyond one year. The following table reconciles cash, cash equivalents and restricted cash per the balance sheet to the statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 58,577 $ 59,272 $ 171,434 Restricted cash 560 560 560 Total cash, cash equivalents, and restricted cash $ 59,137 $ 59,832 $ 171,994 Marketable securities The Company invests funds in U.S. government debt securities, U.S. government-sponsored enterprise debt securities and corporate debt securities with original maturities at the date of purchase greater than three months as marketable securities. The marketable securities are classified as available-for-sale and carried at fair value. The Company considers all available-for-sale securities, including those with maturity dates beyond 12 months, as available to support current operational liquidity needs and therefore classifies all securities with maturity dates beyond three months at the date of purchase as current assets. Changes in the fair value of marketable securities are recorded in other comprehensive income (loss) as net unrealized gains (losses) on marketable securities. The Company recognized net unrealized gain of $5.6 million, and unrealized losses of $2.9 million and $0.5 million, for the years ended December 31, 2023, 2022 and 2021, respectively. The Company assesses its available-for-sale debt securities under the available-for-sale debt security impairment model in ASC 326 as of each reporting date in order to determine if a portion of any decline in fair value below carrying value recognized on its available-for-sale debt securities is the result of a credit loss. The Company records credit losses in the consolidated statements of operations and comprehensive loss as credit loss expense within other expense, net, which is limited to the difference between the fair value and the amortized cost of the marketable security. To date, the Company has not recorded any credit losses on its available-for-sale debt securities. Accrued interest receivable related to the Company’s available-for-sale debt securities is presented within prepaid expenses and other current assets Interest income on investments The Company recognizes interest income from investments in money market funds and available-for-sale debt securities, including accretion of discount or amortization of premium, on an accrual basis. For the years ended December 31, 2023, 2022 and 2021, the Company recognized $27.0 million, $4.6 million and $0.3 million in interest income, respectively. Interest income, net is included within other income, net on the consolidated statements of operations and comprehensive loss. Property and Equipment, net Property and equipment are recorded at cost. Expenditures for major renewals or betterments that extend the useful lives of property and equipment are capitalized; expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is calculated on a straight-line basis over the estimated useful lives of the related asset. Property and equipment are depreciated as follows: Estimated Useful Life (in Years) Laboratory equipment 5 Computers and software 3-5 Leasehold improvements Shorter of the useful life or the remaining term of the lease Leases The Company measures its lease obligations in accordance with ASC 842, Leases, (“ASC 842”), which requires lessees to recognize a right-of-use (“ROU”) asset and lease liability for most lease arrangements. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as ROU assets and short-term and long-term lease liabilities, as applicable. The Company has elected not to recognize leases with an original term of one year or less on the balance sheet. The Company typically only includes an initial lease term in its assessment of a lease arrangement. The Company considers its renewal options and extensions within the arrangements and the Company includes these options when it is reasonably certain to extend the term of the lease. Assumptions made by the Company at the commencement date are re-evaluated upon occurrence of certain events, including a lease modification. A lease modification results in a separate contract when the modification grants the lessee an additional right of use not included in the original lease and when lease payments increase commensurate with the standalone price for the additional right of use. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease. When a lease modification does not result in a separate contract, it is accounted for as a contract modification. A contract modification requires the Company to reassess the classification of the lease to determine if it is an operating lease or a financing lease. The Company does not have any financing leases. Entities may elect to not separate lease and non-lease components. The Company has elected to account for lease and non-lease components together as a single lease component. The Company recognizes an ROU asset and lease liability as of the transition date or contract modification date based on the present value of the future lease payments over the lease term. ASC 842 requires lessees to use the rate implicit in the lease unless it is not readily determinable and then it may use its incremental borrowing rate (“IBR”) to discount the future minimum lease payments. The Company's lease arrangement does not provide an implicit rate; therefore, the Company uses its IBR to discount the future minimum lease payments. The Company determines its IBR based on its credit rating, current economic information available as of the transition date or modification date, as well as the identified lease term. The Company’s ROU asset and related lease liability are not sensitive to changes in the Company’s IBR. Prospectively, the Company will remeasure the lease liability at the present value using the same IBR that was in effect as of the transition date or contract modification date and adjust the ROU assets for straight-line rent expense. Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Fair Value Measurements ASC Topic 820, Fair Value Measurement (“ASC 820”), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3 — Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. At December 31, 2023, investments include U.S. Treasury securities, U.S. government-sponsored enterprise securities, and corporate bonds, which are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company believes that the carrying amounts of the Company’s consolidated financial instruments, including prepaid expenses and other current assets, accounts receivable, accounts payable, and accrued expenses approximate fair value due to the short-term nature of those instruments. Segment Information Operating segments are defined as components of an entity 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’s Chief Executive Officer is its chief operating decision-maker and views operations and manages the Company’s business in one operating segment operating in the United States and the U.K. Revenue Recognition To date all revenue has been generated from the Company’s agreements with AbbVie Biotechnology Ltd (“AbbVie”), executed in October 2018 and terminated as of December 2022, and Janssen Pharmaceuticals, Inc. (“Janssen”), executed in February 2019, amended in December 2020 and terminated as of March 2023. Please refer to Note 12 below for details of ASC 606 application to the Company’s agreements with AbbVie and Janssen. The Company first evaluates collaboration arrangements to determine whether the arrangement (or part of the arrangement) represents a collaborative arrangement pursuant to ASC Topic 808, Collaborative Arrangements, based on the risks and rewards and activities of the parties pursuant to the contractual arrangement. The Company accounts for any collaborative arrangement or elements within the contract that are deemed to be a collaborative arrangement, and not a customer relationship, in accordance with ASC 808. To date, the Company has not recognized any amounts for collaborative arrangements in accordance with ASC 808. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. The Company accounts for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods or services to be transferred can be identified, (iv) the arrangement has commercial substance and (v) collection of substantially all of the consideration to which the Company will be entitled in exchange for the goods or services that will be transferred to the customer is probable. Performance obligations are promised goods or services in a contract to transfer a distinct good or service to the customer. Promised goods or services are considered distinct when: (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. Options to purchase additional goods or services are considered to be marketing offers and are to be accounted for as separate contracts when the customer elects such options, unless the Company determines the option provides a material right which would not be provided without entering into the contract. If, however, an option is determined to provide a material right that would not be provided without entering into a contract, a portion of the transaction price is allocated to such option. The Company estimates the transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price. The Company also evaluates whether instances in which the timing of payments by customers do not match the timing of performance obligation satisfaction contain an element of financing and adjusts the transaction price for the effect of the financing component, if any. The Company’s transactions with customers may include development and regulatory milestone payments. The Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the customer’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and, if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenue and net income (loss) in the period of adjustment. For sales-based royalties, including milestone payments based on the level of sales, the Company determines whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales-based royalty relates, the Company recognizes revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The Company allocates the transaction price based on the estimated standalone selling price of the identified performance obligations. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction, and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time. When the Company receives payments from customers based on billing schedules established in each contract, up-front payments and fees will be recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts will be recorded as accounts receivable when the Company’s right to consideration is unconditional. Research and Development Expenses Research and development expenses are expensed as incurred and consist of costs incurred in performing research and development activities, including compensation related expenses for research and development personnel, preclinical and clinical activities including cost of supply and contract research organizations, overhead expenses including facilities expenses, materials and supplies, amounts paid to consultants and outside service providers, costs related to compliance and license costs, and depreciation of equipment. Upfront license payments related to acquired technologies which have not yet reached technological feasibility and have no alternative future use are also included in research and development expense. Research Contract and Development Costs and Accruals The Company has entered into various research development service arrangements under which vendors perform various services on behalf of the Company. The Company records accrued expenses for estimated costs incurred under the arrangements. When evaluating the adequacy of the accrued expenses, the Company analyzes the progress of the studies, trials or other services performed, including invoices received and contracted costs. Judgments and estimates are made in determining the accrued expense balances at the end of each reporting period. Equity-Based Compensation The Company issues stock options, restricted common stock, and restricted stock units to certain employees and non-employees, including directors. The Company accounts for restricted common stock and restricted stock unit expense based on the grant date fair value, which is generally the market price of the Company’s common stock on the date of grant, which is recognized over the requisite service period of the award, which is generally the vesting period, on a straight-line basis. The Company accounts for stock option compensation expense based on the grant date fair value of the respective award, determined using the Black-Scholes option-pricing model, which is recognized over the requisite service period of the award, which is generally the vesting period, on a straight-line basis. The Company classifies equity-based compensation expense in its consolidated statements of operations and comprehensive loss in the same way the award recipient’s salary and related costs are classified or in which the award recipient’s service payments are classified. The Company recognizes forfeitures as they occur. Please refer to Note 9 for additional information. Comprehensive Loss Comprehensive loss is the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Comprehensive loss includes net loss and the change in accumulated other comprehensive loss for the period. The Company recognized net unrealized gains of $5.6 million and unrealized losses of $2.9 million and $0.5 million for the years ended December 31, 2023, 2022 and 2021, respectively. Income Taxes Since inception, the Company recorded income taxes in accordance with FASB ASC Topic 740, Income Taxes (“ASC 740”), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on temporary differences between the financial statement basis and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established when it is more likely than not that some portion of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. At December 31, 2023 and 2022, the Company had not identified any significant uncertain tax positions. Common stock warrants The Company’s common stock warrants are evaluated pursuant to ASC 480, Distinguishing Liabilities from Equity (“ASC 480”), and ASC 815, Derivatives and Hedging (“ASC 815”). The Company classifies its freestanding warrants as (i) liabilities, if the warrant terms allow settlement of the warrant exercise in cash, or (ii) equity, if the warrant terms only allow settlement in shares of common stock. Please refer to Note 8 below for the application to the Company’s pre-funded warrants.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	Fair Value of Financial Assets and Liabilities The tables below present information about the Company’s financial assets that are measured at fair value on a recurring basis as of December 31, 2023 and 2022 (in thousands) and indicate the level within the fair value hierarchy where each measurement is classified. Fair Value Measurements at December 31, 2023 Total Level 1 Level 2 Level 3 Assets: Cash equivalents $ 57,988 $ 57,988 $ — $ — Marketable securities: U.S. Treasury securities 573,394 — 573,394 — U.S. government-sponsored enterprise securities 54,906 — 54,906 — Corporate bonds 17,472 — 17,472 — Total assets $ 703,760 $ 57,988 $ 645,772 $ — Fair Value Measurements at December 31, 2022 Total Level 1 Level 2 Level 3 Assets: Cash equivalents $ 58,814 $ 38,942 $ 19,872 $ — Marketable securities: U.S. Treasury securities 177,932 — 177,932 — U.S. government-sponsored enterprise securities 12,396 — 12,396 — Commercial paper 9,860 — 9,860 — Corporate bonds 88,788 — 88,788 — Total assets $ 347,790 $ 38,942 $ 308,848 $ — Cash equivalents consist of money market funds as of December 31, 2023 and money market funds and U.S. Treasury securities as of December 31, 2022. The money market funds included in the tables above invest in U.S. government securities that are valued using quoted market prices. Accordingly, money market funds are categorized as Level 1 as of December 31, 2023 and 2022. Marketable securities included in the tables above consist of U.S. Treasury securities, U.S. government- sponsored enterprise securities and corporate bonds as of December 31, 2023 and U.S. Treasury securities, U.S. government- sponsored enterprise securities, corporate bonds and commercial paper as of December 31, 2022, and these securities are categorized as Level 2 as of December 31, 2023 and 2022. During the years ended December 31, 2023 and 2022, no assets were transferred between the fair value hierarchy categories. The Company had no liabilities measured at fair value on a recurring basis at December 31, 2023 and 2022.

Marketable securities

Marketable securities	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable securities	Marketable securities The following tables summarize the Company’s investments in marketable securities classified as available-for-sale (in thousands): As of December 31, 2023 Maturity Amortized Gross Gross Aggregate Marketable securities: U.S. Treasury securities within 3 years $ 570,964 $ 2,499 $ (69) $ 573,394 U.S. government-sponsored enterprise securities less than 1 year 54,997 — (91) 54,906 Corporate bonds less than 1 year 17,498 — (26) 17,472 Total marketable securities $ 643,459 $ 2,499 $ (186) $ 645,772 As of December 31, 2022 Maturity Amortized Gross Gross Aggregate Marketable securities: U.S. Treasury securities less than 1 year $ 179,854 $ — $ (1,922) $ 177,932 U.S. government-sponsored enterprise securities within 2 years 12,500 — (104) 12,396 Commercial paper less than 1 year 9,860 — — 9,860 Corporate bonds within 2 years 90,076 — (1,288) 88,788 Total marketable securities $ 292,290 $ — $ (3,314) $ 288,976 The Company determined that there was no material change in the credit risk of the above marketable securities during the years ended December 31, 2023 and 2022. As such, an allowance for credit losses was not recognized. As of December 31, 2023, the Company does not intend to sell such securities and it is not more likely than not that the Company will be required to sell the securities before recovery of its amortized cost basis.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Property and Equipment, Net At December 31, 2023 and 2022, property and equipment, net consists of the following (in thousands): December 31, 2023 2022 Laboratory equipment $ 7,068 $ 6,094 Computers and software 709 596 Leasehold improvements 611 611 Construction in progress 652 — 9,040 7,301 Less: Accumulated depreciation and amortization (6,273) (5,182) $ 2,767 $ 2,119 Depreciation and amortization expense was $1.1 million, $1.0 million and $1.0 million for the years ended December 31, 2023, 2022 and 2021, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases The Company entered into a lease arrangement for its corporate headquarters in Waltham, Massachusetts. In August 2021, the Company exercised its one-time extension right for its existing lease for 32,405 square feet of office and laboratory space through May 2025, as provided for under the terms of the lease. Since the exercise of the one-time extension right for its existing lease did not qualify to be accounted for as a separate lease, the Company accounted for the exercise of the one-time extension right as a contract modification. The Company reassessed the lease classification for the Company’s corporate headquarters as of the effective date of the modification using the modified terms and conditions and the facts and circumstances as of that date. This included using the remaining economic life of the underlying asset on that date, the discount rate for the lease on that date and a remeasurement and reallocation of the remaining consideration in the contract on that date. The Company concluded that the lease continues to be classified as an operating lease, reassessed the IBR as of the effective date of the modification, and remeasured the lease liability and ROU asset. Supplemental balance sheet information Supplemental operating lease balance sheet information is summarized as follows (in thousands): December 31, 2023 Operating lease right-of-use assets $ 2,133 Accrued expenses (1) $ 1,628 Operating lease liabilities 716 Total operating lease liabilities $ 2,344 (1) The short-term portion of operating lease liabilities is included within accrued expenses on the consolidated balance sheet. Other supplemental information Other supplemental operating lease information is summarized as follows (in thousands, except for years and discount rate): Year Ended December 31, 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 1,700 Weighted average remaining lease term 1.4 years Weighted average discount rate 6.5 % Maturities of lease commitments Maturities of operating lease commitments as of December 31, 2023 were as follows (in thousands): Year ending December 31, Totals 2024 1,732 2025 728 Total lease payments $ 2,460 Less: imputed interest 116 Present value of operating lease liabilities $ 2,344 During the years ended December 31, 2023, 2022 and 2021 the Company recognized operating lease expense of $1.6 million, $1.6 million and $1.3 million, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses At December 31, 2023 and 2022 accrued expenses consist of the following (in thousands): December 31, 2023 2022 Payroll and related expenses $ 8,528 $ 6,569 Research and development activities 5,818 4,265 Current portion of operating lease liability 1,628 1,494 Other expenses 1,104 853 $ 17,078 $ 13,181

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock The common stock have the following characteristics: Voting The holders of common stock are entitled to one vote for each share of common stock held. Dividends The holders of shares of common stock are entitled to receive dividends, if and when declared by the Company’s board of directors. Cash dividends may not be declared or paid to holders of shares of common stock until all unpaid dividends on any preferred shares outstanding have been paid in accordance with their terms. As of December 31, 2023 and 2022, no preferred shares were outstanding. No dividends have been declared or paid by the Company to the holders of common stock since the issuance of the common stock. Liquidation Holders of the common stock are entitled to receive distributions of cash, including in the event of a liquidation or dissolution of the Company, which preference is junior to the liquidation preference of any preferred stockholders. After any preferred stockholders have received their respective preferred distributions, any assets remaining for distribution shall be distributed to the holders of preferred or common shares determined on an as-converted basis. Sale of PIPE Shares and Pre-Funded Warrants In February 2023, the Company entered into a securities purchase agreement with existing investors, pursuant to which it sold, in a private placement, the PIPE Shares and the Pre-Funded Warrants. The Pre-Funded Warrants were immediately exercisable upon issuance at an exercise price of $0.0001 per share and had no expiry date. The Company received aggregate net proceeds of approximately $99.8 million after deducting offering expenses. The Pre-Funded Warrants generally could not be exercised if the holder’s aggregate beneficial ownership would be more than 9.99% of the total issued and outstanding shares of the Company’s common stock following such exercise. The exercise price and number of shares of common stock issuable upon the exercise of the Pre-Funded Warrants were subject to adjustment in the event of any stock dividends and splits, reverse stock split, recapitalization, reorganization or similar transaction, as described in the Pre-Funded Warrants. In connection with the issuance and sale of the PIPE Shares and the Pre-Funded Warrants, the Company granted the investors certain registration rights with respect to the PIPE Shares and the shares issuable upon exercise of the Pre-Funded Warrants. The Pre-Funded Warrants were evaluated pursuant to ASC 480 and ASC 815. The Company classified the Pre-Funded Warrants as a component of permanent stockholders’ equity within additional paid-in capital and were recorded at the issuance date using a relative fair value allocation method. The Pre-Funded Warrants were equity classified because they were freestanding financial instruments that are legally detachable and separately exercisable, were immediately exercisable, did not embody an obligation for the Company to repurchase its common shares, permitted the holders to receive a fixed number of common shares upon exercise, were indexed to the Company’s common shares and met the equity classification criteria. The Company valued the Pre-Funded Warrants at issuance, concluding their sales price approximated their fair value, and allocated net proceeds from the sale proportionately to the PIPE Shares and Pre-Funded Warrants, of which $29.9 million and $69.9 million, respectively, net of issuance costs, was recorded as a component of additional paid-in capital. Common Stock Warrants During the year ended December 31, 2023, 1,980,188 shares of common stock were issued upon the net exercise of 1,980,198 Pre-Funded Warrants.

Equity-Based Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Equity Based Compensation	Equity-Based Compensation In connection with the Company’s initial public offering in July 2019, the Company adopted the 2019 Equity Incentive Plan (the “Original 2019 Plan”) in June 2019, which replaced the 2018 Stock Incentive Plan. The board of directors adopted the Amended and Restated 2019 Equity Incentive Plan (the “A&R 2019 Plan”) on April 27, 2022, which was subsequently approved by the Company’s stockholders on June 8, 2022, to revise the total annual compensation that may be awarded to the Company’s non-employee directors thereunder. The A&R 2019 Plan provides for the grant of stock options, restricted stock awards, stock bonus awards, cash awards, stock appreciation right, restricted stock units, and performance awards to directors, officers and employees of the Company, as well as consultants and advisors of the Company. As a result of the automatic increase provision of the A&R 2019 Plan, the number of shares of common stock available for issuance thereunder increased by 1.5 million shares in January 2023. As of December 31, 2023, there were a total of 1.2 million shares available for future award grants under the A&R 2019 Plan. The Company recognized equity-based compensation expense in the consolidated statements of operations and comprehensive loss, by award type, as follows (in thousands): Year Ended December 31, 2023 2022 2021 Stock options $ 30,684 $ 25,828 $ 19,894 Restricted stock units 9,849 2,764 403 Employee Stock Purchase Plan 410 450 604 Restricted common stock — 6 283 Total $ 40,943 $ 29,048 $ 21,184 The following table summarizes the allocation of equity-based compensation expense in the consolidated statements of operations and comprehensive loss, by expense category (in thousands): Year Ended December 31, 2023 2022 2021 Research and development expense $ 19,629 $ 13,518 $ 9,866 General and administrative expense 21,314 15,530 11,318 Total $ 40,943 $ 29,048 $ 21,184 Restricted Stock Units The following table summarizes the restricted stock units activity during the year ended December 31, 2023: Number of Shares Weighted Unvested restricted stock units as of December 31, 2022 249,090 $ 43.85 Granted 929,080 31.85 Vested (62,085) 43.92 Forfeited (5,790) 33.41 Unvested restricted stock units as of December 31, 2023 1,110,295 $ 33.86 As of December 31, 2023, the Company had unrecognized equity-based compensation expense of $27.9 million related to the restricted stock units, which is expected to be recognized over a weighted average period of 2.87 years. The total fair value of restricted stock units vested during the years ended December 31, 2023, 2022 and 2021 was approximately $2.0 million, $0.2 million and $2.1 million, respectively. Stock Options The following table summarizes the Company’s stock option activity during the year ended December 31, 2023: Number of Weighted Weighted Aggregate (in years) (in thousands) Outstanding as of December 31, 2022 5,263,553 $ 24.94 Granted 1,239,304 35.77 Exercised (584,959) 15.43 Forfeited or expired (30,641) 48.68 Outstanding as of December 31, 2023 5,887,257 $ 28.04 7.26 $ 36,563 Options exercisable as of December 31, 2023 3,798,171 $ 23.20 6.62 $ 34,841 The following table provides certain information related to the stock options granted, vested, and exercised during the years ended December 31, 2023, 2022 and 2021, in thousands, except for per option values: Year Ended December 31, 2023 2022 2021 Weighted-average fair value of options granted, per option $ 26.11 $ 28.88 $ 26.16 Total cash received from exercises of stock options $ 9,027 $ 5,175 $ 9,536 Total intrinsic value of stock options exercised $ 20,487 $ 8,507 $ 39,335 The following table summarizes the assumptions used in determining the fair value of the options granted during the years ended December 31, 2023, 2022 and 2021: Year Ended December 31, 2023 2022 2021 Risk‑free interest rate range 3.58% to 4.73% 1.64% to 4.20% 1.04% to 1.35% Weighted-average expected term 6.0 years 6.0 years 6.0 years Expected volatility range 82.28% to 85.26% 85.16% to 87.03% 86.22% to 87.55% Weighted-average expected volatility 84.95% 86.81% 87.09% The expected term of options granted has been determined based upon the simplified method, because the Company does not have sufficient historical information regarding its options to derive the expected term. Under this approach, the expected term for employee and director stock options is the mid-point between the weighted average of vesting period and the contractual term. The Company determines the volatility for options granted based on the historical volatility of the Company’s own historical volatility in addition to a representative group of publicly traded companies for which historical information is available. The historical volatility is generally calculated based on a period of time commensurate with the expected term assumption. The risk-free interest rate is based on a zero-coupon U.S. Treasury instrument with terms consistent with the term of the stock options. The Company has not paid and does not anticipate paying cash dividends on shares of common stock; therefore, the expected dividend yield is assumed to be zero. As of December 31, 2023, the Company had unrecognized equity-based compensation expense of $51.5 million related to stock options issued to employees and non-employees, which is expected to be recognized over a weighted average period of 2.19 years. Restricted Common Stock As of and for the year-ended December 31, 2023, the Company had no recognized or unrecognized equity-based compensation expense or outstanding awards related to the restricted common stock. The total fair value of restricted common stock awards vested during the years ended December 31, 2022 and 2021 was approximately $0.1 million, and $5.0 million, respectively. Employee Stock Purchase Plan In 2019, the Company adopted the 2019 Employee Stock Purchase Plan (“ESPP”), which became effective on June 26, 2019. The Company initially reserved 300,000 shares of common stock for sale under the ESPP. As a result of the automatic increase provision of the ESPP, the number of shares of common stock available for issuance under the ESPP increased by 0.4 million shares on January 1, 2023. The ESPP is a qualified, compensatory plan under Section 423 of the Internal Revenue Code and offers substantially all employees opportunity to purchase up to $25,000 of common stock per year at 15% discount to the lower of the beginning of the offering period price or the end of the offering period price. Compensation expense for discounted purchases under the ESPP is measured using the Black-Scholes model to compute the fair value of the lookback provision plus the purchase discount and is recognized as compensation expense over the course of the offering period.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of loss before income taxes for the years ended December 31, 2023, 2022 and 2021 (in thousands) were: Year Ended December 31, 2023 2022 2021 U.S. $ (151,993) $ (59,036) $ (95,542) Foreign 278 62 — Total $ (151,715) $ (58,974) $ (95,542) The components of the income tax expense for the years ended December 31, 2023, 2022 and 2021 (in thousands) were: Year Ended December 31, 2023 2022 2021 Current: Federal $ — $ — $ — State 342 55 — Foreign 38 12 — Total current tax provision 380 67 — Deferred: Federal — — — State — — — Foreign — — — Total deferred tax provision — — — Total income tax provision $ 380 $ 67 $ — The effective income tax rate differed from the amount computed by applying the federal statutory rate to the Company’s loss before income taxes as follows: Year Ended December 31, 2023 2022 2021 Tax effected at statutory rate 21.00 % 21.00 % 21.00 % State taxes 7.42 7.84 9.31 Equity-based compensation 0.74 (1.02) 5.33 Non-deductible expenses (2.92) (3.87) (0.01) Federal research and development credits 3.11 6.83 3.34 Change in valuation allowance (29.60) (30.89) (38.97) (0.25) % (0.11) % — % Deferred tax assets and liabilities consist of the following at December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 57,348 $ 49,969 Capitalized research and experimental expenditures 48,984 22,147 Research and development credit carryforwards 23,212 17,101 Equity-based compensation 9,740 5,649 Fixed and intangible assets 3,175 3,332 Reserves and accruals 2,467 1,764 Lease liabilities 640 1,049 Deferred revenue — 128 Total deferred tax assets 145,566 101,139 Valuation allowance (144,328) (99,417) Subtotal 1,238 1,722 Right-of-use assets (583) (960) Fixed assets (434) (472) Prepaid expense (221) (290) Total net deferred tax assets $ — $ — As required by ASC 740, the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are composed principally of collaboration revenue that has been recognized as taxable but remains deferred for book reporting as of year end and net operating loss carryfowards. The Company has determined that it is more likely than not that the Company will not realize the benefits of its federal and state deferred tax assets, and, as a result, a valuation allowance of $144.3 million and $99.4 million has been established at each of December 31, 2023 and 2022. The change in the valuation allowance was $44.9 million and $16.7 million for the years ended December 31, 2023 and 2022. Beginning in 2022, Tax Cuts and Jobs Act (“Tax Act”) amended Section 174 and now requires U.S.-based and non-U.S.-based research and experimental (“R&E”) expenditures to be capitalized and amortized over a period of five or 15 years, respectively, for amounts paid in tax years starting after December 31, 2021. Prior to the Tax Act amendment, Section 174 allowed taxpayers to immediately deduct R&E expenditures in the year paid or incurred. The Company has applied this required change in accounting method beginning in 2023 and the computation may be adjusted pending future IRS guidance. The Company has incurred net operating losses (“NOLs”) from inception. At December 31, 2023, the Company has federal and state NOL carryforwards of approximately $201.6 million and $237.4 million, respectively, available to reduce future taxable income, with $197.7 million of the federal NOLs having an unlimited carryover life and the remaining federal and the state NOLs beginning to expire in 2037. As of December 31, 2023, the Company also has federal and state research and development tax credit carryforwards of approximately $17.3 million and $7.4 million, respectively, to offset future income taxes, which will begin to expire beginning in December 2032. The Company’s NOL carryforwards are subject to review and possible adjustment by the appropriate taxing authorities. The Company continues to review its historic ownership changes to determine if there are any IRC 382 limitations which may limit the annual utilization of the NOLs. The Company follows the provisions of ASC 740-10, “Accounting for Uncertainty in Income Taxes,” which specifies how tax benefits for uncertain tax positions are to be recognized, measured, and recorded in financial statements; requires certain disclosures of uncertain tax matters; specifies how reserves for uncertain tax positions should be classified on the balance sheet; and provides transition and interim period guidance, among other provisions. As of December 31, 2023 and 2022, the Company had no unrecognized tax benefits. The Company has not identified any uncertain positions with respect to the credit computations. The Company’s policy is to recognize interest and penalties accrued on any uncertain tax positions as a component of income tax expense, if any, in its statements of operations. For the years ended December 31, 2023 and 2022, no estimated interest or penalties were recognized on uncertain tax positions. The Company does not expect any significant change in its uncertain tax positions in the next 12 months. The Company files U.S. federal and state income tax returns and is generally subject to income tax examinations by these authorities for all tax years after December 31, 2020. Currently, no federal or state income tax returns are under examination by the respective income tax authorities. Provision for Income Taxes The Company recorded income tax expense of $0.4 million for the year ended December 31, 2023, income tax expense of $0.1 million for the year ended December 31, 2022 and $0.0 million for the year ended December 31, 2021. Despite the collaboration revenue, the Company continues to maintain a valuation allowance against all deferred tax assets. The Company believes that it is more likely than not that the Company will not realize a future tax benefit of these attributes, as the Company’s research programs continue to require significant investment and future revenue is subject to uncertainties. Ultimate realization of any deferred tax asset is dependent on the Company’s ability to generate sufficient future taxable income in the appropriate tax jurisdiction before the expiration of carryforward periods, if any.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Guarantees and Indemnifications The Company entered, and intends to continue to enter, into separate indemnification agreements with directors, officers, and certain other key employees, in addition to the indemnification provided for in the restated certificate of incorporation and amended and restated bylaws, as amended. These agreements, among other things, require the Company to indemnify directors, officers, and certain other key employees for certain expenses, including attorneys’ fees, judgments, penalties, fines, and settlement amounts actually incurred by these individuals in any action or proceeding arising out of their service to the Company or any of its subsidiaries or any other company or enterprise to which these individuals provide services at the Company’s request. Subject to certain limitations, the indemnification agreements also require the Company to advance expenses incurred by directors, officers, and key employees for the defense of any action for which indemnification is required or permitted. The Company has standard indemnification arrangements in its leases for laboratory and office space that require it to indemnify the landlord against any liability for injury, loss, accident, or damage from any claims, actions, proceedings, or costs resulting from certain acts, breaches, violations, or non-performance under the Company’s lease. Through December 31, 2023, the Company had not experienced any losses related to these indemnification obligations, and no material claims were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Legal Proceedings The Company is not currently a party to any material legal proceedings.

Option and License Agreements

Option and License Agreements	12 Months Ended
	Dec. 31, 2023
Option and License Agreements
Option and License Agreements	Option and License Agreements AbbVie Agreement Overview In October 2018, the Company entered into a 5-year collaboration and option agreement with AbbVie (the “AbbVie Agreement”), a research-based global biopharmaceutical company that held Series A and Series B Convertible Preferred Shares of the Company at the time the AbbVie Agreement was executed. Pursuant to this agreement, AbbVie paid the Company an upfront, non-refundable amount of $100.0 million. In exchange, the Company: (i) assumed the obligation to perform research and development activities to identify and develop compounds directed at multiple fibrosis indications (grouped into four research programs) through completion of Investigational New Drug (IND)-enabling studies, and (ii) granted AbbVie options to license the results of research and development in exchange for separate upfront option-exercise fees. In June 2022, AbbVie informed the Company that it had decided to exercise its right to terminate the AbbVie Agreement for convenience and the AbbVie Agreement terminated in December 2022. Prior to the AbbVie Agreement termination, AbbVie held the right to exercise its license options for molecules with the selected pharmacological profiles by providing written notice to the Company and paying an option exercise fee of $20.0 million per option exercised (up to three in total). Effective upon the termination of the AbbVie Agreement, all rights and licenses granted thereunder immediately terminated and were returned to the Company. AbbVie Agreement Accounting Analysis The Company concluded that the performance obligations in the agreement had included the research services for the four research programs. The Company has concluded that the unexercised license options were marketing offers as the options did not provide any discounts or other rights that would be considered a material right in the arrangement. All other performance obligations were determined to be immaterial in the context of the contract. The Company estimated the standalone selling price of each research program based on internal and external costs to perform the research plus a reasonable profit margin of 10%. The total estimated cost of the research and development services reflected the nature of the services to be performed and the Company’s best estimate of the length of time required to perform the services. The Company recognized revenue as research and development services were provided based on the costs incurred to date, as such costs have a direct relationship between the Company’s effort and the progress made towards satisfying its performance obligations to AbbVie. Changes to the estimated cost of internal and external development services were recognized in the period of change as a cumulative catch-up adjustment. These research and development performance obligations were recognized as revenue and completed through the effective date of the termination in December 2022. The Company determined that the transaction price included only the non-refundable up-front payment of $100.0 million and recorded this amount as deferred revenue as of December 31, 2018. The option exercise payments were not included in the transaction price, as the Company determined that the agreed upon fees represent fair value of such options. The milestone payments were fully constrained, as a result of the uncertainty regarding whether AbbVie would exercise any of the options and whether any of the associated milestones would be achieved. There were no changes to the transaction price prior to the AbbVie Agreement termination. The Company also considered the existence of any significant financing component within the AbbVie Agreement given its upfront payment structure. Based upon this assessment, the Company concluded that the up-front payment was provided for valid business reasons and not for the purpose of providing financing. Accordingly, the Company has concluded that the upfront payment structure of the AbbVie Agreement did not result in the existence of a significant financing component. On August 25, 2020, AbbVie exercised its option to license and control further development and commercialization of Morphic’s αvβ6–specific integrin inhibitors for the treatment of fibrotic diseases including idiopathic pulmonary fibrosis (IPF) and additional indications. In connection with the exercise of the option, AbbVie paid the Company $20.0 million. Upon option exercise, the Company evaluated whether the change to the contract should be treated as the continuation of the current arrangement or as a separate agreement. As the additional performance obligations were deemed to be distinct and priced consistent with the standalone selling price of such obligations, the Company concluded that the license and any additional performance obligations should be accounted for as a separate contract. The potential performance obligations included in the arrangement were (1) the license to research, develop and commercialize αvβ6–specific integrin inhibitors, and (2) options to purchase materials that were manufactured prior to option exercise (the “Material Options”). The Company concluded that the Material Options were not material rights as the price to purchase the materials approximated the standalone selling price. Based on this conclusion, the full transaction price of $20.0 million was allocated to the license and recognized upon delivery in 2020. The Company will not receive any additional payments for this program from AbbVie as the license terminated upon termination of the AbbVie Agreement. Upon receipt of notification of the exercise of the right to terminate the AbbVie Agreement, the Company concluded that there was a contract modification to an existing contract under ASC 606 because the notification of termination of the AbbVie Agreement resulted in a reduction in scope of the Company’s responsibilities for the three remaining research programs thereunder. The terms of the AbbVie Agreement termination notification did not include any additional promised goods or services. As a result of the notification from AbbVie, the Company recognized revenue of $57.7 million on a cumulative catch-up basis using an updated measure of progress towards satisfying the research and development services performance obligations thereunder. Effective upon the termination of the AbbVie Agreement, all rights and licenses granted thereunder immediately terminated and were returned to the Company and no research and development costs were incurred or revenue was recognized in connection with the AbbVie Agreement after the termination. The following table summarizes research and development costs incurred and revenue recognized in connection with Company's performance under the AbbVie Agreement during the years ended December 31, 2022 and 2021 (in thousands): Year Ended December 31, 2022 2021 Revenue recognized $ 60,500 $ 11,197 Costs incurred $ 631 $ 5,376 Janssen Agreement Overview In February 2019, the Company entered into a research collaboration and option agreement with Janssen (“Janssen Agreement”), a subsidiary of Johnson & Johnson, to discover and develop novel integrin therapeutics for patients with conditions not adequately addressed by current therapies. The Janssen Agreement focused on three integrin targets, each target the subject of a research program, with a limited ability to substitute integrin targets for others, not explored by the Company, if research results were not favorable. Under the terms of the agreement, Janssen paid the Company an upfront fee of $10.0 million for the first two research programs in 2019 and in December 2020 the Company reached an agreement with Janssen to commence work on the third research program and Janssen agreed to pay $5.0 million for the third research program commencement fee. In addition, Janssen reimbursed the Company for all internal and external costs and expenses incurred during the term of the agreement at agreed-upon contractual rates. In December 2021, Janssen informed the Company that they had decided not to exercise its options on the first two integrin targets, thus also discontinuing those two research programs. The Company focused its remaining efforts on the third integrin research program which included the potential development of integrin antibody activators. In January 2023, Janssen informed the Company that it had decided to exercise its right to terminate the Janssen Agreement for convenience and the effective date of the termination of Janssen Agreement was in March 2023. Janssen Agreement Accounting Analysis The Company has concluded that the performance obligations in the agreement include the research services for the three research programs and three options to license the outcomes of those research programs, which were determined to provide Janssen with material rights. All other performance obligations were determined to be immaterial in the context of the contract. The Company estimated the standalone selling price of each research program based on internal and external costs to perform the research plus a reasonable profit margin. The total estimated cost of the research and development services reflect the nature of the services to be performed and the Company’s best estimate of the length of time required to perform the services. The Company estimated the standalone selling price of each material right by determining the discount provided to the estimated standalone selling price of comparable options and applying appropriate likelihood of exercise, which includes the appropriate probability of successfully completing the research efforts. Based on the standalone selling prices determined, the Company allocates the total transaction price among the programs and material rights. The Company recognized revenue as research services were provided based on the costs incurred to date, as such costs had a direct relationship between the Company’s effort and the progress made towards satisfying its performance obligations to Janssen. Transaction price allocated to the material rights was deferred and recognized as revenue when Janssen terminated the agreement and the option period expired. Changes in estimates of total internal and external costs expected to be incurred were recognized in the period of change as a cumulative catch-up adjustment. The Company determined that the transaction price included: the non-refundable up-front payment of $10.0 million for the first two programs, $5.0 million non-refundable up-front payment for the third program, and the estimated reimbursement payments at agreed upon contractual rates that were received from Janssen for the Company’s on-going research services. The option exercise payments were not included in the transaction price. The milestone payments were fully constrained, as a result of the uncertainty regarding whether Janssen would exercise any of the options and whether any of the associated milestones would be achieved. The Company also considered the existence of any significant financing component within the Janssen Agreement given its upfront payment structure. Based upon this assessment, the Company concluded that the up-front payment was provided for valid business reasons and not for the purpose of providing financing. Accordingly, the Company has concluded that the upfront payment structure of the Janssen Agreement does not result in the existence of a significant financing component. Upon notification of discontinuation of the two research programs and related options, the Company concluded that there was a contract modification to an existing contract under ASC 606 because the December 2021 notification resulted in a reduction in scope of the Company’s responsibilities under the Janssen Agreement. The December 2021 notification did not include any additional promised goods and services. Subsequent to the modification, there were two remaining performance obligations pursuant to the Janssen Agreement, research services for the remaining research program and a material right for Janssen’s remaining license option. The Company concluded that the remaining research services to be provided to satisfy the third research program were not distinct from its existing research services, and as a result treated the modification as part of the original contract (as opposed to a separate contract). Therefore, the Company updated the transaction price, which included the remaining deferred revenue and estimated variable consideration for research services and allocated the updated transaction price to the remaining performance obligations based on the estimated standalone selling prices at the date of the contract modification. For the research services, the effect that the contract modification had on the transaction price and the measure of progress towards satisfying the performance obligation of $1.9 million has been recognized on a cumulative catch-up basis. The transaction price allocated to the remaining material right of $0.5 million was deferred and was recognized upon expiration of the option period. The accounting for any previously satisfied performance obligations as of the contract modification date are not affected by the modification. Upon notification of termination for convenience of the Janssen Agreement in January 2023, certain remaining research and development performance obligations under the Janssen Agreement were completed, including the termination of the third integrin research program thereunder, through the effective date of the termination in March 2023. In March 2023, the Company recognized the remaining deferred revenue allocated to the material right upon expiration of the Janssen license option. The following table summarizes research and development costs incurred and revenue recognized in connection with the Company's performance under the Janssen Agreement during the years ended December 31, 2023, 2022 and 2021 (in thousands): Year Ended December 31, 2023 2022 2021 Reimbursement revenue $ 51 $ 3,159 $ 4,944 Upfront payment revenue 470 7,149 3,653 Total revenue recognized $ 521 $ 10,308 $ 8,597 Costs incurred $ 51 $ 2,637 $ 4,426 In Q4 2022, the Company recognized additional revenue of $3.0 million on a cumulative catch-up basis as a result of changes to the estimated costs associated with the remaining effort required to complete the research services for the third research program. The amount of future expected cost estimates had decreased based on a change in expected effort and based on the timing of the research services. As of December 31, 2022, the Company had $0.5 million due from Janssen recorded in accounts receivable. As of December 31, 2022, $0.5 million of deferred revenue was classified as current in the accompanying consolidated balance sheets based on the period over which the revenue was expected to be recognized. As of December 31, 2023 the Company had no remaining deferred revenue related to the Janssen Agreement, as all of the performance obligations thereunder were satisfied as of the effective date of the termination.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing net loss allocable to common stockholders by the weighted-average common shares outstanding during the period, without consideration of common stock equivalents. For periods with net income, diluted net income per share is calculated by adjusting the weighted-average shares outstanding for the dilutive effect of common share equivalents, including stock options, restricted stock units, and restricted common stock outstanding for the period as determined using the treasury stock method. For purposes of the diluted net loss per share calculation, common share equivalents are excluded from the calculation if their effect would be anti-dilutive. As such, basic and diluted net loss per share applicable to common stockholders are the same for periods with a net loss. The following tables illustrate the determination of basic and diluted net loss per share for each period presented (in thousands, except share and per share data): Year Ended December 31, 2023 2022 2021 Net loss $ (152,095) $ (59,041) $ (95,542) Weighted average common shares outstanding, basic and diluted 42,390,554 38,112,498 35,797,969 Net loss per share, basic and diluted $ (3.59) $ (1.55) $ (2.67) In February 2023, the Company sold and issued the Pre-Funded Warrants (see Note 8). The shares of common stock into which the Pre-Funded Warrants may be exercised are considered outstanding from the date of issuance of the Pre-Funded Warrants for the purposes of computing basic loss per share because the shares may be issued for little or no consideration and because the Pre-Funded Warrants were fully vested and immediately exercisable upon issuance. The following table sets forth the outstanding common stock equivalents, presented based on amounts outstanding at each period end, that have been excluded from the calculation of diluted net loss per share for the periods indicated because their inclusion would have been anti-dilutive (in common stock equivalent shares, as applicable): Year Ended December 31, 2023 2022 2021 Restricted stock units 1,110,295 249,090 7,000 Stock options 5,887,257 5,263,553 4,781,565 Restricted common stock — — 2,171 6,997,552 5,512,643 4,790,736 In addition to the securities listed in the table above, as of December 31, 2023 the Company had reserved 1,493,422 shares of common stock for sale under the ESPP, which, if issued, would be anti-dilutive if included in calculation of diluted net loss per share for the year ended December 31, 2023.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit Plan In 2016, the Company adopted a qualified retirement plan, the Morphic Therapeutic, Inc. 401(k) Plan to provide retirement income for eligible employees through employee contributions and employer matching contributions. Matching contributions totaled $1.2 million, $0.6 million and $0.6 million for the years ended December 31, 2023, 2022 and 2021, respectively.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net loss	$ (152,095)	$ (59,041)	$ (95,542)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2023 shares	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Terminated	false
Praveen P. Tipirneni [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On December 27, 2023, Praveen P. Tipirneni, M.D., the Chief Executive Officer and a Director of the Company, adopted a trading arrangement for the sale of shares of the Company’s common stock that is intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c) (the “Tipirneni Plan”). The Tipirneni Plan, which is scheduled to expire on April 28, 2025, provides for the sale of up to 149,492 shares of common stock pursuant to the terms thereof.
Name	Praveen P. Tipirneni, M.D.
Title	Chief Executive Officer and a Director
Non-Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 27, 2023
Arrangement Duration	488 days
Aggregate Available	149,492	149,492
William D. DeVaul [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On December 28, 2023, William D. DeVaul, Esq., the General Counsel and Secretary of the Company, terminated an existing trading arrangement for the sale of securities of the Company’s common stock that he had previously adopted (the “Terminated DeVaul Plan”) and adopted a trading arrangement for the sale of shares of the Company’s common stock that is intended to satisfy the affirmative defense conditions of Securities Exchange Act Rule 10b5-1(c) (the “New DeVaul Plan”). The Terminated DeVaul Plan was adopted on September 30, 2022, was set to expire on March 29, 2024 and provided for the sale of up to 234,132 shares of common stock pursuant to the terms thereof. As of the date of termination of the Terminated DeVaul Plan, Mr. DeVaul had sold 11,658 shares of common stock thereunder. The New DeVaul Plan, which is scheduled to expire on March 28, 2025, provides for the sale of up to 200,950 shares of common stock pursuant to the terms thereof.
William D. DeVaul, September 2022 Plan [Member] | William D. DeVaul [Member]
Trading Arrangements, by Individual
Name	William D. DeVaul, Esq.
Title	General Counsel and Secretary
Adoption Date	September 30, 2022
Rule 10b5-1 Arrangement Terminated	true
Termination Date	December 28, 2023
Aggregate Available	234,132	234,132
William D. DeVaul, New Plan [Member] | William D. DeVaul [Member]
Trading Arrangements, by Individual
Name	William D. DeVaul, Esq.
Title	General Counsel and Secretary
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 28, 2023
Arrangement Duration	456 days
Aggregate Available	200,950	200,950

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Consolidation	The consolidated financial statements include the accounts of Morphic Holding, Inc. and its wholly-owned subsidiaries, Morphic Therapeutic, Inc., Morphic Therapeutic UK Ltd and Morphic Security Corporation. All intercompany balances have been eliminated in consolidation.
Basis of Accounting	These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).
Use of Estimates and Summary of Significant Accounting Policies	Use of Estimates and Summary of Significant Accounting Policies The preparation of financial statements in accordance with GAAP requires management to make estimates and judgments that may affect the reported amounts of assets and liabilities and related disclosures of contingent assets and liabilities at the date of the financial statements and the related reporting of revenues and expenses during the reporting period. Significant estimates of accounting reflected in these consolidated financial statements include, but are not limited to, estimates related to revenue recognition and accrued research and development expenses. Actual results for accrued research and development expenses could differ from those estimates. On March 2, 2022, the Company incorporated Morphic Therapeutic UK Ltd in London, U.K., to support Company functions outside of the United States. The geographic location of all long-lived assets of the Company continues to be the United States. The functional reporting currency of Morphic Therapeutic UK Ltd is the United States Dollar. Foreign currency remeasurement is included in other income (expense) in the Company’s consolidated statements of operations.
Concentration of Credit Risk and Off-Balance Sheet Risk	Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, and accounts receivable. The Company’s cash and cash equivalents are held at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The primary objectives for the Company’s investment portfolio are the preservation of capital and maintenance of liquidity. The Company’s investment policy allows funds to be held outside bank accounts, but to be invested only in readily marketable fixed income instruments with readily ascertainable market values, denominated and payable in United States Dollars including obligations of the U.S. government, U.S. government-sponsored enterprises, U.S. government agencies and highly rated corporate debt obligations, including commercial paper and corporate bonds, and money market funds registered according to Rule 2a-7 of the Investment Company Act of 1940. Investments in the money market fund shall be consistent with approved instruments and assets under management must be at least $1.0 billion. The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign-hedging arrangements.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. At December 31, 2023, cash and cash equivalents include bank demand deposits and money market funds that invest primarily in U.S. government securities. At December 31, 2022, cash and cash equivalents include bank demand deposits, money market funds that invest primarily in U.S. government securities, and U.S. Treasury securities. Cash equivalents are stated at cost, which approximates fair value.
Marketable securities	Marketable securities
Interest income on investments	Interest income on investments Interest income, net is included within other income, net on the consolidated statements of operations and comprehensive loss.
Property and Equipment, net	Property and Equipment, net Property and equipment are recorded at cost. Expenditures for major renewals or betterments that extend the useful lives of property and equipment are capitalized; expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is calculated on a straight-line basis over the estimated useful lives of the related asset. Property and equipment are depreciated as follows: Estimated Useful Life (in Years) Laboratory equipment 5 Computers and software 3-5 Leasehold improvements Shorter of the useful life or the remaining term of the lease
Leases	Leases The Company measures its lease obligations in accordance with ASC 842, Leases, (“ASC 842”), which requires lessees to recognize a right-of-use (“ROU”) asset and lease liability for most lease arrangements. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as ROU assets and short-term and long-term lease liabilities, as applicable. The Company has elected not to recognize leases with an original term of one year or less on the balance sheet. The Company typically only includes an initial lease term in its assessment of a lease arrangement. The Company considers its renewal options and extensions within the arrangements and the Company includes these options when it is reasonably certain to extend the term of the lease. Assumptions made by the Company at the commencement date are re-evaluated upon occurrence of certain events, including a lease modification. A lease modification results in a separate contract when the modification grants the lessee an additional right of use not included in the original lease and when lease payments increase commensurate with the standalone price for the additional right of use. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease. When a lease modification does not result in a separate contract, it is accounted for as a contract modification. A contract modification requires the Company to reassess the classification of the lease to determine if it is an operating lease or a financing lease. The Company does not have any financing leases. Entities may elect to not separate lease and non-lease components. The Company has elected to account for lease and non-lease components together as a single lease component. The Company recognizes an ROU asset and lease liability as of the transition date or contract modification date based on the present value of the future lease payments over the lease term. ASC 842 requires lessees to use the rate implicit in the lease unless it is not readily determinable and then it may use its incremental borrowing rate (“IBR”) to discount the future minimum lease payments. The Company's lease arrangement does not provide an implicit rate; therefore, the Company uses its IBR to discount the future minimum lease payments. The Company determines its IBR based on its credit rating, current economic information available as of the transition date or modification date, as well as the identified lease term. The Company’s ROU asset and related lease liability are not sensitive to changes in the Company’s IBR. Prospectively, the Company will remeasure the lease liability at the present value using the same IBR that was in effect as of the transition date or contract modification date and adjust the ROU assets for straight-line rent expense.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.
Fair Value Measurements	Fair Value Measurements ASC Topic 820, Fair Value Measurement (“ASC 820”), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves. Level 3 — Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. At December 31, 2023, investments include U.S. Treasury securities, U.S. government-sponsored enterprise securities, and corporate bonds, which are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The Company believes that the carrying amounts of the Company’s consolidated financial instruments, including prepaid expenses and other current assets, accounts receivable, accounts payable, and accrued expenses approximate fair value due to the short-term nature of those instruments.
Segment Information	Segment Information Operating segments are defined as components of an entity 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’s Chief Executive Officer is its chief operating decision-maker and views operations and manages the Company’s business in one operating segment operating in the United States and the U.K.
Revenue Recognition	Revenue Recognition To date all revenue has been generated from the Company’s agreements with AbbVie Biotechnology Ltd (“AbbVie”), executed in October 2018 and terminated as of December 2022, and Janssen Pharmaceuticals, Inc. (“Janssen”), executed in February 2019, amended in December 2020 and terminated as of March 2023. Please refer to Note 12 below for details of ASC 606 application to the Company’s agreements with AbbVie and Janssen. The Company first evaluates collaboration arrangements to determine whether the arrangement (or part of the arrangement) represents a collaborative arrangement pursuant to ASC Topic 808, Collaborative Arrangements, based on the risks and rewards and activities of the parties pursuant to the contractual arrangement. The Company accounts for any collaborative arrangement or elements within the contract that are deemed to be a collaborative arrangement, and not a customer relationship, in accordance with ASC 808. To date, the Company has not recognized any amounts for collaborative arrangements in accordance with ASC 808. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. The Company accounts for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods or services to be transferred can be identified, (iv) the arrangement has commercial substance and (v) collection of substantially all of the consideration to which the Company will be entitled in exchange for the goods or services that will be transferred to the customer is probable. Performance obligations are promised goods or services in a contract to transfer a distinct good or service to the customer. Promised goods or services are considered distinct when: (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. Options to purchase additional goods or services are considered to be marketing offers and are to be accounted for as separate contracts when the customer elects such options, unless the Company determines the option provides a material right which would not be provided without entering into the contract. If, however, an option is determined to provide a material right that would not be provided without entering into a contract, a portion of the transaction price is allocated to such option. The Company estimates the transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price. The Company also evaluates whether instances in which the timing of payments by customers do not match the timing of performance obligation satisfaction contain an element of financing and adjusts the transaction price for the effect of the financing component, if any. The Company’s transactions with customers may include development and regulatory milestone payments. The Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the customer’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and, if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenue and net income (loss) in the period of adjustment. For sales-based royalties, including milestone payments based on the level of sales, the Company determines whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales-based royalty relates, the Company recognizes revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The Company allocates the transaction price based on the estimated standalone selling price of the identified performance obligations. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction, and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time.
Research and Development Expenses	Research and Development Expenses Research and development expenses are expensed as incurred and consist of costs incurred in performing research and development activities, including compensation related expenses for research and development personnel, preclinical and clinical activities including cost of supply and contract research organizations, overhead expenses including facilities expenses, materials and supplies, amounts paid to consultants and outside service providers, costs related to compliance and license costs, and depreciation of equipment. Upfront license payments related to acquired technologies which have not yet reached technological feasibility and have no alternative future use are also included in research and development expense.
Research Contract and Development Costs And Accruals	Research Contract and Development Costs and Accruals The Company has entered into various research development service arrangements under which vendors perform various services on behalf of the Company. The Company records accrued expenses for estimated costs incurred under the arrangements. When evaluating the adequacy of the accrued expenses, the Company analyzes the progress of the studies, trials or other services performed, including invoices received and contracted costs. Judgments and estimates are made in determining the accrued expense balances at the end of each reporting period.
Equity-Based Compensation	Equity-Based Compensation The Company issues stock options, restricted common stock, and restricted stock units to certain employees and non-employees, including directors. The Company accounts for restricted common stock and restricted stock unit expense based on the grant date fair value, which is generally the market price of the Company’s common stock on the date of grant, which is recognized over the requisite service period of the award, which is generally the vesting period, on a straight-line basis. The Company accounts for stock option compensation expense based on the grant date fair value of the respective award, determined using the Black-Scholes option-pricing model, which is recognized over the requisite service period of the award, which is generally the vesting period, on a straight-line basis. The Company classifies equity-based compensation expense in its consolidated statements of operations and comprehensive loss in the same way the award recipient’s salary and related costs are classified or in which the award recipient’s service payments are classified. The Company recognizes forfeitures as they occur.
Comprehensive Loss	Comprehensive Loss
Income Taxes	Income Taxes Since inception, the Company recorded income taxes in accordance with FASB ASC Topic 740, Income Taxes (“ASC 740”), which provides for deferred taxes using an asset and liability approach. Under this method, deferred tax assets and liabilities are determined based on temporary differences between the financial statement basis and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established when it is more likely than not that some portion of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. At December 31, 2023 and 2022, the Company had not identified any significant uncertain tax positions.
Common stock warrants	Common stock warrants The Company’s common stock warrants are evaluated pursuant to ASC 480, Distinguishing Liabilities from Equity (“ASC 480”), and ASC 815, Derivatives and Hedging (“ASC 815”). The Company classifies its freestanding warrants as (i) liabilities, if the warrant terms allow settlement of the warrant exercise in cash, or (ii) equity, if the warrant terms only allow settlement in shares of common stock. Please refer to Note 8 below for the application to the Company’s pre-funded warrants.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of reconciled cash, cash equivalents, and restricted cash	The following table reconciles cash, cash equivalents and restricted cash per the balance sheet to the statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 58,577 $ 59,272 $ 171,434 Restricted cash 560 560 560 Total cash, cash equivalents, and restricted cash $ 59,137 $ 59,832 $ 171,994
Schedule of reconciled cash, cash equivalents, and restricted cash	The following table reconciles cash, cash equivalents and restricted cash per the balance sheet to the statements of cash flows (in thousands): December 31, 2023 2022 2021 Cash and cash equivalents $ 58,577 $ 59,272 $ 171,434 Restricted cash 560 560 560 Total cash, cash equivalents, and restricted cash $ 59,137 $ 59,832 $ 171,994
Schedule of property and equipment, net	Depreciation is calculated on a straight-line basis over the estimated useful lives of the related asset. Property and equipment are depreciated as follows: Estimated Useful Life (in Years) Laboratory equipment 5 Computers and software 3-5 Leasehold improvements Shorter of the useful life or the remaining term of the lease At December 31, 2023 and 2022, property and equipment, net consists of the following (in thousands): December 31, 2023 2022 Laboratory equipment $ 7,068 $ 6,094 Computers and software 709 596 Leasehold improvements 611 611 Construction in progress 652 — 9,040 7,301 Less: Accumulated depreciation and amortization (6,273) (5,182) $ 2,767 $ 2,119

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Summary of financial assets measured at fair value on recurring basis	The tables below present information about the Company’s financial assets that are measured at fair value on a recurring basis as of December 31, 2023 and 2022 (in thousands) and indicate the level within the fair value hierarchy where each measurement is classified. Fair Value Measurements at December 31, 2023 Total Level 1 Level 2 Level 3 Assets: Cash equivalents $ 57,988 $ 57,988 $ — $ — Marketable securities: U.S. Treasury securities 573,394 — 573,394 — U.S. government-sponsored enterprise securities 54,906 — 54,906 — Corporate bonds 17,472 — 17,472 — Total assets $ 703,760 $ 57,988 $ 645,772 $ — Fair Value Measurements at December 31, 2022 Total Level 1 Level 2 Level 3 Assets: Cash equivalents $ 58,814 $ 38,942 $ 19,872 $ — Marketable securities: U.S. Treasury securities 177,932 — 177,932 — U.S. government-sponsored enterprise securities 12,396 — 12,396 — Commercial paper 9,860 — 9,860 — Corporate bonds 88,788 — 88,788 — Total assets $ 347,790 $ 38,942 $ 308,848 $ —

Marketable securities (Tables)

Marketable securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of investments in marketable securities classified as available for sale	The following tables summarize the Company’s investments in marketable securities classified as available-for-sale (in thousands): As of December 31, 2023 Maturity Amortized Gross Gross Aggregate Marketable securities: U.S. Treasury securities within 3 years $ 570,964 $ 2,499 $ (69) $ 573,394 U.S. government-sponsored enterprise securities less than 1 year 54,997 — (91) 54,906 Corporate bonds less than 1 year 17,498 — (26) 17,472 Total marketable securities $ 643,459 $ 2,499 $ (186) $ 645,772 As of December 31, 2022 Maturity Amortized Gross Gross Aggregate Marketable securities: U.S. Treasury securities less than 1 year $ 179,854 $ — $ (1,922) $ 177,932 U.S. government-sponsored enterprise securities within 2 years 12,500 — (104) 12,396 Commercial paper less than 1 year 9,860 — — 9,860 Corporate bonds within 2 years 90,076 — (1,288) 88,788 Total marketable securities $ 292,290 $ — $ (3,314) $ 288,976

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of property and equipment, net	Depreciation is calculated on a straight-line basis over the estimated useful lives of the related asset. Property and equipment are depreciated as follows: Estimated Useful Life (in Years) Laboratory equipment 5 Computers and software 3-5 Leasehold improvements Shorter of the useful life or the remaining term of the lease At December 31, 2023 and 2022, property and equipment, net consists of the following (in thousands): December 31, 2023 2022 Laboratory equipment $ 7,068 $ 6,094 Computers and software 709 596 Leasehold improvements 611 611 Construction in progress 652 — 9,040 7,301 Less: Accumulated depreciation and amortization (6,273) (5,182) $ 2,767 $ 2,119

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Summary of supplemental information	Supplemental operating lease balance sheet information is summarized as follows (in thousands): December 31, 2023 Operating lease right-of-use assets $ 2,133 Accrued expenses (1) $ 1,628 Operating lease liabilities 716 Total operating lease liabilities $ 2,344 (1) The short-term portion of operating lease liabilities is included within accrued expenses on the consolidated balance sheet. Other supplemental information Other supplemental operating lease information is summarized as follows (in thousands, except for years and discount rate): Year Ended December 31, 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 1,700 Weighted average remaining lease term 1.4 years Weighted average discount rate 6.5 %
Summary of lease maturities	Maturities of operating lease commitments as of December 31, 2023 were as follows (in thousands): Year ending December 31, Totals 2024 1,732 2025 728 Total lease payments $ 2,460 Less: imputed interest 116 Present value of operating lease liabilities $ 2,344

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of accrued expenses	At December 31, 2023 and 2022 accrued expenses consist of the following (in thousands): December 31, 2023 2022 Payroll and related expenses $ 8,528 $ 6,569 Research and development activities 5,818 4,265 Current portion of operating lease liability 1,628 1,494 Other expenses 1,104 853 $ 17,078 $ 13,181

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of equity based compensation expense	The Company recognized equity-based compensation expense in the consolidated statements of operations and comprehensive loss, by award type, as follows (in thousands): Year Ended December 31, 2023 2022 2021 Stock options $ 30,684 $ 25,828 $ 19,894 Restricted stock units 9,849 2,764 403 Employee Stock Purchase Plan 410 450 604 Restricted common stock — 6 283 Total $ 40,943 $ 29,048 $ 21,184 The following table summarizes the allocation of equity-based compensation expense in the consolidated statements of operations and comprehensive loss, by expense category (in thousands): Year Ended December 31, 2023 2022 2021 Research and development expense $ 19,629 $ 13,518 $ 9,866 General and administrative expense 21,314 15,530 11,318 Total $ 40,943 $ 29,048 $ 21,184
Summary of restricted stock units	The following table summarizes the restricted stock units activity during the year ended December 31, 2023: Number of Shares Weighted Unvested restricted stock units as of December 31, 2022 249,090 $ 43.85 Granted 929,080 31.85 Vested (62,085) 43.92 Forfeited (5,790) 33.41 Unvested restricted stock units as of December 31, 2023 1,110,295 $ 33.86
Summary of stock option activity	The following table summarizes the Company’s stock option activity during the year ended December 31, 2023: Number of Weighted Weighted Aggregate (in years) (in thousands) Outstanding as of December 31, 2022 5,263,553 $ 24.94 Granted 1,239,304 35.77 Exercised (584,959) 15.43 Forfeited or expired (30,641) 48.68 Outstanding as of December 31, 2023 5,887,257 $ 28.04 7.26 $ 36,563 Options exercisable as of December 31, 2023 3,798,171 $ 23.20 6.62 $ 34,841
Summary of information relating to stock	The following table provides certain information related to the stock options granted, vested, and exercised during the years ended December 31, 2023, 2022 and 2021, in thousands, except for per option values: Year Ended December 31, 2023 2022 2021 Weighted-average fair value of options granted, per option $ 26.11 $ 28.88 $ 26.16 Total cash received from exercises of stock options $ 9,027 $ 5,175 $ 9,536 Total intrinsic value of stock options exercised $ 20,487 $ 8,507 $ 39,335
Summary of assumptions used in determining the fair value of the options granted	The following table summarizes the assumptions used in determining the fair value of the options granted during the years ended December 31, 2023, 2022 and 2021: Year Ended December 31, 2023 2022 2021 Risk‑free interest rate range 3.58% to 4.73% 1.64% to 4.20% 1.04% to 1.35% Weighted-average expected term 6.0 years 6.0 years 6.0 years Expected volatility range 82.28% to 85.26% 85.16% to 87.03% 86.22% to 87.55% Weighted-average expected volatility 84.95% 86.81% 87.09%

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The components of loss before income taxes for the years ended December 31, 2023, 2022 and 2021 (in thousands) were: Year Ended December 31, 2023 2022 2021 U.S. $ (151,993) $ (59,036) $ (95,542) Foreign 278 62 — Total $ (151,715) $ (58,974) $ (95,542)
Schedule of Components of Income Tax Expense	The components of the income tax expense for the years ended December 31, 2023, 2022 and 2021 (in thousands) were: Year Ended December 31, 2023 2022 2021 Current: Federal $ — $ — $ — State 342 55 — Foreign 38 12 — Total current tax provision 380 67 — Deferred: Federal — — — State — — — Foreign — — — Total deferred tax provision — — — Total income tax provision $ 380 $ 67 $ —
Schedule of Effective Income Tax Rate Reconciliation	The effective income tax rate differed from the amount computed by applying the federal statutory rate to the Company’s loss before income taxes as follows: Year Ended December 31, 2023 2022 2021 Tax effected at statutory rate 21.00 % 21.00 % 21.00 % State taxes 7.42 7.84 9.31 Equity-based compensation 0.74 (1.02) 5.33 Non-deductible expenses (2.92) (3.87) (0.01) Federal research and development credits 3.11 6.83 3.34 Change in valuation allowance (29.60) (30.89) (38.97) (0.25) % (0.11) % — %
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets and liabilities consist of the following at December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforwards $ 57,348 $ 49,969 Capitalized research and experimental expenditures 48,984 22,147 Research and development credit carryforwards 23,212 17,101 Equity-based compensation 9,740 5,649 Fixed and intangible assets 3,175 3,332 Reserves and accruals 2,467 1,764 Lease liabilities 640 1,049 Deferred revenue — 128 Total deferred tax assets 145,566 101,139 Valuation allowance (144,328) (99,417) Subtotal 1,238 1,722 Right-of-use assets (583) (960) Fixed assets (434) (472) Prepaid expense (221) (290) Total net deferred tax assets $ — $ —

Option and License Agreements (

Option and License Agreements (Tables)	12 Months Ended
	Dec. 31, 2023
Option and License Agreements
Summary of costs incurred and revenue recognized	The following table summarizes research and development costs incurred and revenue recognized in connection with Company's performance under the AbbVie Agreement during the years ended December 31, 2022 and 2021 (in thousands): Year Ended December 31, 2022 2021 Revenue recognized $ 60,500 $ 11,197 Costs incurred $ 631 $ 5,376 The following table summarizes research and development costs incurred and revenue recognized in connection with the Company's performance under the Janssen Agreement during the years ended December 31, 2023, 2022 and 2021 (in thousands): Year Ended December 31, 2023 2022 2021 Reimbursement revenue $ 51 $ 3,159 $ 4,944 Upfront payment revenue 470 7,149 3,653 Total revenue recognized $ 521 $ 10,308 $ 8,597 Costs incurred $ 51 $ 2,637 $ 4,426

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of basic net income (loss) per share	The following tables illustrate the determination of basic and diluted net loss per share for each period presented (in thousands, except share and per share data): Year Ended December 31, 2023 2022 2021 Net loss $ (152,095) $ (59,041) $ (95,542) Weighted average common shares outstanding, basic and diluted 42,390,554 38,112,498 35,797,969 Net loss per share, basic and diluted $ (3.59) $ (1.55) $ (2.67)
Schedule of common stock equivalent shares	The following table sets forth the outstanding common stock equivalents, presented based on amounts outstanding at each period end, that have been excluded from the calculation of diluted net loss per share for the periods indicated because their inclusion would have been anti-dilutive (in common stock equivalent shares, as applicable): Year Ended December 31, 2023 2022 2021 Restricted stock units 1,110,295 249,090 7,000 Stock options 5,887,257 5,263,553 4,781,565 Restricted common stock — — 2,171 6,997,552 5,512,643 4,790,736

Nature of the Business (Details

Nature of the Business (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				12 Months Ended
	Aug. 11, 2021	May 31, 2023	Feb. 28, 2023	Mar. 31, 2021	Jul. 31, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Subsidiary or Equity Method Investee [Line Items]
Proceeds from issuance of common shares and pre-funded warrants through the private placement						$ 99,799	$ 0	$ 0
Sale of stock, number of shares issued (in shares)						1,518,759
ATM
Subsidiary or Equity Method Investee [Line Items]
Sales of common shares sold in IPO, net of offering costs (in shares)						1,518,759
Proceeds from issuance or sale of equity						$ 84,500
Amount of shares remaining available for sale						10,900
ATM | Open Market Sale Agreement
Subsidiary or Equity Method Investee [Line Items]
Proceeds from issuance of common shares and pre-funded warrants through the private placement	$ 150,000				$ 75,000
Secondary Offering
Subsidiary or Equity Method Investee [Line Items]
Sales of common shares sold in IPO, net of offering costs (in shares)				3,500,000
Public offering price (in dollars per share)				$ 70
Proceeds from issuance of common shares, net				$ 245,000		259,061	0	229,982
Offering costs		$ 16,900		15,000		16,900	$ 1,300	$ 15,000
Gross proceeds from secondary offering				$ 230,000
Private Placement
Subsidiary or Equity Method Investee [Line Items]
Proceeds from issuance or sale of equity			$ 99,800
Sale of stock, number of shares issued (in shares)			848,655
Offering costs						$ 100
Gross proceeds from secondary offering			$ 100,000
Percentage of stockholders holding company stock			5%
Sale of stock (in dollars per share)			$ 35.35
Right to purchase common stock (in shares)			1,980,198
Right to purchase common stock, purchase price (in dollars per share)			$ 35.3499
Exercise price of warrant (in dollars per share)			$ 0.0001
Secondary Offering
Subsidiary or Equity Method Investee [Line Items]
Sale of stock, number of shares issued (in shares)		6,133,334
Public offering price (in dollars per share)		$ 45
Proceeds from issuance of common shares, net		$ 276,000
Gross proceeds from secondary offering		$ 259,100
Underwriters' exercise
Subsidiary or Equity Method Investee [Line Items]
Sale of stock, number of shares issued (in shares)		800,000

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Aug. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Letter of credit	$ 560	$ 560		$ 560
Term of letter of credit (in years)	1 year
Cash and cash equivalents	$ 58,577	59,272	$ 171,434
Restricted cash	560	560	560
Total cash, cash equivalents and restricted cash	$ 59,137	$ 59,832	$ 171,994		$ 102,322

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unrealized gain (loss)	$ 5.6	$ (2.9)	$ (0.5)
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Prepaid expenses and other current assets
Interest income	$ 27	$ 4.6	$ 0.3
Operating segment | segment	1
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets under management	$ 1,000

Basis of Presentation and Sig_6

Basis of Presentation and Significant Accounting Policies - Property and Equipment Net (Details)	Dec. 31, 2023
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in Years)	5 years
Computers and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in Years)	3 years
Computers and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in Years)	5 years

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Assets:
Marketable securities	$ 645,772,000	$ 288,976,000
Fair value on a recurring basis
Assets:
Cash equivalents	57,988,000	58,814,000
Total assets	703,760,000	347,790,000
Liabilities measured at fair value	0	0
Fair value on a recurring basis | U.S. Treasury securities
Assets:
Marketable securities	573,394,000	177,932,000
Fair value on a recurring basis | U.S. government-sponsored enterprise securities
Assets:
Marketable securities	54,906,000	12,396,000
Fair value on a recurring basis | Commercial paper
Assets:
Marketable securities		9,860,000
Fair value on a recurring basis | Corporate bonds
Assets:
Marketable securities	17,472,000	88,788,000
Fair value on a recurring basis | Level 1
Assets:
Cash equivalents	57,988,000	38,942,000
Total assets	57,988,000	38,942,000
Fair value on a recurring basis | Level 1 | U.S. Treasury securities
Assets:
Marketable securities	0	0
Fair value on a recurring basis | Level 1 | U.S. government-sponsored enterprise securities
Assets:
Marketable securities	0	0
Fair value on a recurring basis | Level 1 | Commercial paper
Assets:
Marketable securities		0
Fair value on a recurring basis | Level 1 | Corporate bonds
Assets:
Marketable securities	0	0
Fair value on a recurring basis | Level 2
Assets:
Cash equivalents	0	19,872,000
Total assets	645,772,000	308,848,000
Fair value on a recurring basis | Level 2 | U.S. Treasury securities
Assets:
Marketable securities	573,394,000	177,932,000
Fair value on a recurring basis | Level 2 | U.S. government-sponsored enterprise securities
Assets:
Marketable securities	54,906,000	12,396,000
Fair value on a recurring basis | Level 2 | Commercial paper
Assets:
Marketable securities		9,860,000
Fair value on a recurring basis | Level 2 | Corporate bonds
Assets:
Marketable securities	17,472,000	88,788,000
Fair value on a recurring basis | Level 3
Assets:
Cash equivalents	0	0
Total assets	0	0
Fair value on a recurring basis | Level 3 | U.S. Treasury securities
Assets:
Marketable securities	0	0
Fair value on a recurring basis | Level 3 | U.S. government-sponsored enterprise securities
Assets:
Marketable securities	0	0
Fair value on a recurring basis | Level 3 | Commercial paper
Assets:
Marketable securities		0
Fair value on a recurring basis | Level 3 | Corporate bonds
Assets:
Marketable securities	$ 0	$ 0

Marketable securities (Details)

Marketable securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Marketable securities
Amortized cost	$ 643,459	$ 292,290
Gross unrealized holding gains	2,499	0
Gross unrealized holding losses	(186)	(3,314)
Aggregate estimated fair value	645,772	288,976
Accrued interest receivable	4,400	1,400
U.S. Treasury securities
Marketable securities
Amortized cost	570,964	179,854
Gross unrealized holding gains	2,499	0
Gross unrealized holding losses	(69)	(1,922)
Aggregate estimated fair value	573,394	177,932
U.S. government-sponsored enterprise securities
Marketable securities
Amortized cost	54,997	12,500
Gross unrealized holding gains	0	0
Gross unrealized holding losses	(91)	(104)
Aggregate estimated fair value	54,906	12,396
Commercial paper
Marketable securities
Amortized cost		9,860
Gross unrealized holding gains		0
Gross unrealized holding losses		0
Aggregate estimated fair value		9,860
Corporate bonds
Marketable securities
Amortized cost	17,498	90,076
Gross unrealized holding gains	0	0
Gross unrealized holding losses	(26)	(1,288)
Aggregate estimated fair value	$ 17,472	$ 88,788

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 9,040	$ 7,301
Less: Accumulated depreciation and amortization	(6,273)	(5,182)
Property and equipment, net	2,767	2,119
Depreciation and amortization	1,100	1,000	$ 1,000
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,068	6,094
Computers and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	709	596
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	611	611
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 652	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Aug. 31, 2021 ft²
Lessee, Lease, Description [Line Items]
Accrued expenses | $	$ 1.6	$ 1.6	$ 1.3
Office and Laboratory Space
Lessee, Lease, Description [Line Items]
Area of land (square feet) | ft²				32,405

Leases - Summary of supplementa

Leases - Summary of supplemental information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease right-of-use assets	$ 2,133	$ 3,514
Accrued expenses	$ 1,628	$ 1,494
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued and other current expenses	Accrued and other current expenses
Operating lease liabilities	$ 716	$ 2,344
Total operating lease liabilities	2,344
Cash paid for amounts included in the measurement of operating lease liabilities	$ 1,700
Weighted average remaining lease term	1 year 4 months 24 days
Weighted average discount rate	6.50%

Leases - Maturities of lease co

Leases - Maturities of lease commitments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 1,732
2025	728
Total lease payments	2,460
Less: imputed interest	116
Present value of operating lease liabilities	$ 2,344

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Payroll and related expenses	$ 8,528	$ 6,569
Research and development activities	5,818	4,265
Current portion of operating lease liability	1,628	1,494
Other expenses	1,104	853
Total	$ 17,078	$ 13,181

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Feb. 28, 2023 USD ($) $ / shares	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 $ / shares shares
Equity Transactions under the Open Market Sale Agreement
Voting rights per share number | vote		1
Preferred shares, shares outstanding (in shares)		0	0
Common stock, dividends declared (in dollars per share) | $ / shares		$ 0	$ 0
Common stock, dividends paid (in dollars per share) | $ / shares		$ 0	$ 0
Pre-Funded Warrant Shares [Member]
Equity Transactions under the Open Market Sale Agreement
Proceeds from issuance of common shares, net | $		$ 69.9
Issuance of common stock upon exercise of pre-funded warrants (in shares)		1,980,188
Warrants exercised (in shares)		1,980,198
Pre- funded warrants (in shares)		0
Private Placement
Equity Transactions under the Open Market Sale Agreement
Exercise price of warrant (in dollars per share) | $ / shares	$ 0.0001
Proceeds from issuance or sale of equity | $	$ 99.8
Beneficial ownership	9.99%
Private Placement | Pre-Funded Warrant Shares [Member]
Equity Transactions under the Open Market Sale Agreement
Proceeds from issuance of common shares, net | $		$ 29.9

Equity-Based Compensation - 201

Equity-Based Compensation - 2019 equity incentive plan (Details) - 2019 Equity Incentive Plan - shares shares in Millions	Dec. 31, 2023	Jan. 31, 2023
Equity Based Compensation
Shares available for future issuance (in shares)		1.5
Number of shares available for issuance (in shares)	1.2

Equity-Based Compensation - Equ

Equity-Based Compensation - Equity based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity Based Compensation
Total equity-based compensation expense	$ 40,943	$ 29,048	$ 21,184
Research and development expense
Equity Based Compensation
Total equity-based compensation expense	19,629	13,518	9,866
General and administrative expense
Equity Based Compensation
Total equity-based compensation expense	21,314	15,530	11,318
Stock options
Equity Based Compensation
Total equity-based compensation expense	30,684	25,828	19,894
Restricted stock units
Equity Based Compensation
Total equity-based compensation expense	9,849	2,764	403
Employee Stock Purchase Plan
Equity Based Compensation
Total equity-based compensation expense	410	450	604
Restricted common stock
Equity Based Compensation
Total equity-based compensation expense	$ 0	$ 6	$ 283

Equity-Based Compensation - Res

Equity-Based Compensation - Restricted stock units activity (Details) - Restricted stock units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Weighted Average Fair Value per Share at Issuance
Unrecognized equity based compensation expense	$ 27.9
Unrecognized equity based compensation expense expected period for recognition	2 years 10 months 13 days
Aggregate intrinsic value	$ 2	$ 0.2	$ 2.1
2019 Equity Incentive Plan
Number of Shares
Outstanding at the beginning (in shares)	249,090
Granted (in shares)	929,080
Vested (in shares)	(62,085)
Forfeited (in shares)	(5,790)
Outstanding at the end (in shares)	1,110,295
Weighted Average Fair Value per Share at Issuance
Outstanding at the beginning (in dollars per share)	$ 43.85
Granted (in dollars per share)	31.85
Vested (in dollars per share)	43.92
Forfeited (in dollars per share)	33.41
Outstanding at the end (in dollars per share)	$ 33.86

Equity-Based Compensation - Sto

Equity-Based Compensation - Stock option awards (Details) - Stock options $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Number of Shares
Outstanding at the beginning (in shares) | shares	5,263,553
Granted (in shares) | shares	1,239,304
Exercised (in shares) | shares	(584,959)
Forfeited or expired (in shares) | shares	(30,641)
Outstanding at the end (in shares) | shares	5,887,257
Options exercisable at the end (in shares) | shares	3,798,171
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share) | $ / shares	$ 24.94
Granted (in dollars per share) | $ / shares	35.77
Exercised (in dollars per share) | $ / shares	15.43
Forfeited or expired (in dollars per share) | $ / shares	48.68
Outstanding at the end (in dollars per share) | $ / shares	28.04
Options exercisable at the end (in dollars per share) | $ / shares	$ 23.20
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Expected term (in years)	7 years 3 months 3 days
Options exercisable at the end (in years)	6 years 7 months 13 days
Outstanding at the end | $	$ 36,563
Options exercisable at the end | $	34,841
Unrecognized equity based compensation expense | $	$ 51,500
Unrecognized equity based compensation expense expected period for recognition	2 years 2 months 8 days

Equity-Based Compensation - Inf

Equity-Based Compensation - Information related to options granted, vested and exercised (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Weighted-average fair value of options granted, per option (in dollars per share)	$ 26.11	$ 28.88	$ 26.16
Total cash received from exercises of stock options	$ 9,027	$ 5,175	$ 9,536
Total intrinsic market value of stock options exercised	$ 20,487	$ 8,507	$ 39,335
Stock options | 2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk‑free interest rate, minimum	3.58%	1.64%	1.04%
Risk‑free interest rate, maximum	4.73%	4.20%	1.35%
Weighted-average expected term	6 years	6 years	6 years
Expected volatility, minimum	82.28%	85.16%	86.22%
Expected volatility, maximum	85.26%	87.03%	87.55%
Weighted-average expected volatility	84.95%	86.81%	87.09%

Equity-Based Compensation - R_2

Equity-Based Compensation - Restricted common stock activity (Details) - Restricted common stock - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity Based Compensation
Unrecognized equity based compensation expense	$ 0
Aggregate intrinsic value		$ 100,000	$ 5,000,000

Equity-Based Compensation - Emp

Equity-Based Compensation - Employee Stock Purchase Plan (Details) - ESPP - USD ($)	12 Months Ended
	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2019
Equity Based Compensation
Shares authorized (in shares)			300,000
Shares available for future grants (in shares)		400,000
Discount rate to purchase common stock	15%
Maximum
Equity Based Compensation
Amount of common shares available for purchase per employee per year	$ 25,000

Income Taxes - Components of lo

Income Taxes - Components of loss before income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
U.S.	$ (151,993)	$ (59,036)	$ (95,542)
Foreign	278	62	0
loss before income taxes	$ (151,715)	$ (58,974)	$ (95,542)

Income Taxes - Components of in

Income Taxes - Components of income tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 0	$ 0	$ 0
State	342	55	0
Foreign	38	12	0
Total current tax provision	380	67	0
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total deferred tax provision	0	0	0
Total income tax provision	$ 380	$ 67	$ 0

Income Taxes - Effective income

Income Taxes - Effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax effected at statutory rate	21%	21%	21%
State taxes	7.42%	7.84%	9.31%
Equity-based compensation	0.74%	(1.02%)	5.33%
Non-deductible expenses	(2.92%)	(3.87%)	(0.01%)
Federal research and development credits	3.11%	6.83%	3.34%
Change in valuation allowance	(29.60%)	(30.89%)	(38.97%)
Effective income tax rate	(0.25%)	(0.11%)	0%

Income Taxes - Deferred tax ass

Income Taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 57,348	$ 49,969
Capitalized research and experimental expenditures	48,984	22,147
Research and development credit carryforwards	23,212	17,101
Equity-based compensation	9,740	5,649
Fixed and intangible assets	3,175	3,332
Reserves and accruals	2,467	1,764
Lease liabilities	640	1,049
Deferred revenue	0	128
Total deferred tax assets	145,566	101,139
Valuation allowance	(144,328)	(99,417)
Subtotal	1,238	1,722
Right-of-use assets	(583)	(960)
Fixed assets	(434)	(472)
Prepaid expense	(221)	(290)
Total net deferred tax assets	$ 0	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 144,328,000	$ 99,417,000
Income tax examination, penalties and interest expense	0	0
Income tax expense (benefit)	380,000	67,000	$ 0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Valuation allowance	144,300,000
Increase (decrease) in valuation allowance	44,900,000
Operating loss carry forwards	201,600,000
Operating loss carryforwards, not subject to expiration	197,700,000
Tax credit carryforward, amount	17,300,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Valuation allowance		99,400,000
Increase (decrease) in valuation allowance		$ 16,700,000
Operating loss carry forwards	237,400,000
Tax credit carryforward, amount	$ 7,400,000

Option and License Agreements -

Option and License Agreements - Narrative (Details) $ in Thousands		1 Months Ended			3 Months Ended	12 Months Ended
	Aug. 25, 2020 USD ($)	Dec. 31, 2020 USD ($)	Feb. 28, 2019 target	Oct. 31, 2018 USD ($) option program	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) program option	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) program	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) program	Dec. 31, 2018 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue						$ 521	$ 70,808	$ 19,794
AbbVie | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Term of arrangement				5 years
Upfront fees received				$ 100,000
Number of research programs | program				4		3
Option exercise fee				$ 20,000
Number of options available for exercise | option				3
Profit margin percentage						10%
Up-front payment included in transaction price											$ 100,000
Option exercise fees received	$ 20,000
Revenue recognized from option exercise									$ 20,000
Revenue recognized						$ 57,700
Collaboration revenue							60,500	11,197
Janssen | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue					$ 500	0	500
Collaboration revenue						$ 521	10,308	$ 8,597
Deferred revenue					500		500
Janssen | Upfront payment revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of research programs | program						3				2
Revenue recognized					$ 3,000
Deferred revenue						$ 500
Number of integrin targets | target			3
Upfront fee for first two research program										$ 10,000
Upfront fee for third research program		$ 5,000
Number of discontinued research programs | program						2		2
Number of options, license | option						3
Collaboration revenue						$ 470	$ 7,149	$ 3,653
Performance obligation recognized						$ 1,900
Janssen | Upfront Payment Revenue, First Two Programs
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of research programs | program						2
Collaboration revenue						$ 10,000
Janssen | Upfront Payment Revenue, Third Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenue						$ 5,000

Option and License Agreements_2

Option and License Agreements - Costs incurred and revenue recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	$ 521	$ 70,808	$ 19,794
Costs incurred	179,207	134,204	115,600
AbbVie | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized		60,500	11,197
Costs incurred		631	5,376
Janssen | Upfront payment revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	470	7,149	3,653
Janssen | Reimbursement revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	51	3,159	4,944
Janssen | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	521	10,308	8,597
Costs incurred	51	$ 2,637	$ 4,426
Janssen | Upfront Payment Revenue, First Two Programs
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	10,000
Janssen | Upfront Payment Revenue, Third Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized	$ 5,000

Net Loss per Share - Basic net

Net Loss per Share - Basic net income (loss) per share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net loss	$ (152,095)	$ (59,041)	$ (95,542)
Weighted average common shares outstanding, basic (in shares)	42,390,554	38,112,498	35,797,969
Weighted average common shares outstanding, diluted (in shares)	42,390,554	38,112,498	35,797,969
Net loss per share, basic (in dollars per share)	$ (3.59)	$ (1.55)	$ (2.67)
Net loss per share, diluted (in dollars per share)	$ (3.59)	$ (1.55)	$ (2.67)

Net Loss per Share- Common stoc

Net Loss per Share- Common stock equivalent shares (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti‑dilutive securities (in shares)	6,997,552	5,512,643	4,790,736
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti‑dilutive securities (in shares)	1,110,295	249,090	7,000
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti‑dilutive securities (in shares)	5,887,257	5,263,553	4,781,565
Restricted common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti‑dilutive securities (in shares)	0	0	2,171
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti‑dilutive securities (in shares)	1,493,422

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Contribution total amount	$ 1.2	$ 0.6	$ 0.6