Vor Biopharma (VOR) 10-K 20 Mar 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Mar. 15, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Registrant Name	VOR BIOPHARMA INC.
Entity Central Index Key	0001817229
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity File Number	001-39979
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-1591163
Entity Address, Address Line One	100 Cambridgepark Drive
Entity Address, Address Line Two	Suite 101
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02140
City Area Code	617
Local Phone Number	655-6580
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		68,168,771
Entity Public Float			$ 136,250,599
Document Financial Statement Error Correction [Flag]	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	VOR
Security Exchange Name	NASDAQ
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Proxy Statement for its 2024 Annual Meeting of Stockholders, to be filed with the Securities and Exchange Commission no later than 120 days after December 31, 2023, are incorporated by reference in Part III of this Annual Report on Form 10-K.
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	42

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 31,360	$ 57,706
Marketable securities	105,815	172,539
Prepaid expenses	3,153	4,368
Other current assets	475	2,337
Total current assets	140,803	236,950
Restricted cash equivalents	2,413	2,413
Property and equipment, net	10,050	12,634
Operating lease right-of-use assets	40,048	44,444
Other assets	4,812	2,925
Total assets	198,126	299,366
Current liabilities:
Accounts payable	815	1,772
Accrued liabilities	10,877	7,889
Operating lease liabilities	3,830	3,272
Other current liabilities	50	186
Total current liabilities	15,572	13,119
Long-term liabilities:
Operating lease liabilities—non-current	31,830	35,640
Total liabilities	47,402	48,759
Stockholders' equity :
Preferred stock, $0.0001 par value; 10,000,000 shares authorized as of December 31, 2023 and December 31, 2022; 0 shares issued and outstanding as of December 31, 2023 and December 31, 2022
Common stock, $0.0001 par value; 400,000,000 shares authorized as of December 31, 2023 and December 31, 2022; 67,901,610, and 66,079,597 shares issued and 67,891,311 and 65,996,138 outstanding as of December 31, 2023 and December 31, 2022, respectively	7	7
Additional paid-in capital	490,874	473,587
Accumulated other comprehensive loss	(77)	(770)
Accumulated deficit	(340,080)	(222,217)
Total stockholders' equity	150,724	250,607
Total liabilities and stockholders' equity	$ 198,126	$ 299,366

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	67,901,610	66,079,597
Common stock, shares outstanding	67,891,311	65,996,138

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development	$ 94,315	$ 64,550
General and administrative	31,721	28,868
Total operating expenses	126,036	93,418
Loss from operations	(126,036)	(93,418)
Other income:
Interest income	8,173	1,324
Total other income	8,173	1,324
Net loss	$ (117,863)	$ (92,094)
Net loss per share attributable to common stockholders, basic	$ (1.75)	$ (2.33)
Net loss per share attributable to common stockholders, diluted	$ (1.75)	$ (2.33)
Weighted-average common shares outstanding, basic	67,191,973	39,551,420
Weighted-average common shares outstanding, diluted	67,191,973	39,551,420
Other comprehensive income (loss):
Unrealized gain (loss) on available for sale investments	$ 693	$ (770)
Total other comprehensive income (loss)	693	(770)
Comprehensive loss	$ (117,170)	$ (92,864)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 216,263	$ 4	$ 346,382		$ (130,123)
Beginning Balance, Shares at Dec. 31, 2021		37,174,741
Issuance of common stock upon vesting of RSUs, vesting and exercise of stock options, and issuance of common stock from ESSP, net of shares withheld for taxes	1,350		1,350
Issuance of common stock upon vesting of RSUs, vesting and exercise of stock options, and issuance of common stock from ESSP, net of shares withheld for taxes, Shares		1,025,193
Issuance of common stock from at-the-market sales agreements	4,356		4,356
Issuance of common stock from at-the-market sales agreements, Shares		866,030
Issuance of common stock from offering and concurrent private placement, net of issuance costs	110,807	$ 3	110,804
Issuance of common stock from offering and concurrent private placement, net of issuance costs, Shares		26,930,174
Stock-based compensation expense	10,695		10,695
Other comprehensive loss, net of tax	(770)			$ (770)
Net Income (Loss)	(92,094)				(92,094)
Ending Balance at Dec. 31, 2022	$ 250,607	$ 7	473,587	(770)	(222,217)
Ending Balance, Shares at Dec. 31, 2022	65,996,138	65,996,138
Issuance of common stock upon vesting of RSUs, vesting and exercise of stock options, and issuance of common stock from ESSP, net of shares withheld for taxes	$ (787)		(787)
Issuance of common stock upon vesting of RSUs, vesting and exercise of stock options, and issuance of common stock from ESSP, net of shares withheld for taxes, Shares		878,510
Issuance of common stock from at-the-market sales agreements	4,712		4,712
Issuance of common stock from at-the-market sales agreements, Shares		1,016,662
Stock-based compensation expense	13,362		13,362
Other comprehensive loss, net of tax	693			693
Net Income (Loss)	(117,863)				(117,863)
Ending Balance at Dec. 31, 2023	$ 150,724	$ 7	$ 490,874	$ (77)	$ (340,080)
Ending Balance, Shares at Dec. 31, 2023	67,891,311	67,891,310

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (117,863)	$ (92,094)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation expense	3,492	2,525
Non-cash lease expense	4,727	3,578
Stock-based compensation	13,362	10,695
Interest amortization on marketable securities	(4,660)	(12)
Changes in operating assets and liabilities:
Operating lease liabilities, net	(3,583)	(10,454)
Prepaid expenses and other current assets	3,270	225
Accounts payable and accrued liabilities	2,850	1,114
Other assets	(1,887)	(721)
Net cash used in operating activities	(100,292)	(85,144)
Cash flow from investing activities
Purchases of marketable securities	(74,923)	(123,189)
Proceeds from maturities of marketable securities	147,000	37,560
Purchases of property and equipment	(1,069)	(8,462)
Net cash provided by (used in) investing activities	71,008	(94,091)
Cash flow from financing activities
Proceeds from the issuance of common stock from public offering and concurrent private placement, net of underwriter fees and issuance costs		111,524
Payment of issuance costs related to underwritten public offering and concurrent private placement	(717)
Proceeds from the issuance of common stock from at-the-market sales agreements, net of issuance costs	4,578	4,451
Shares repurchased for tax withholdings upon vesting of restricted stock unit awards	(1,187)
Proceeds from stock option exercises and the issuance of shares under ESPP	264	1,165
Net cash provided by financing activities	2,938	117,140
Net decrease in cash, cash equivalents and restricted cash equivalents	(26,346)	(62,095)
Cash, cash equivalents and restricted cash equivalents, beginning of period	60,119	122,214
Cash, cash equivalents and restricted cash equivalents, end of period	33,773	60,119
Supplemental disclosure of non-cash activities
Right-of-use assets obtained in exchange for lease obligations		23,376
Purchases of property and equipment in accounts payable and accrued liabilities	70	38
Financing costs associated with the sale of common stock included in accounts payable and accrued expenses	$ 27	$ 812

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 31,360	$ 57,706
Restricted cash equivalents	2,413	2,413
Total cash, cash equivalents and restricted cash equivalents as shown on the statements of cash flows	$ 33,773	$ 60,119	$ 122,214

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (117,863)	$ (92,094)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arr Modified Flag	false
Non-Rule 10b51 Arr Modified Flag	false

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of the Business	1. Nature of the Business Vor Biopharma Inc. (the “Company”) is a clinical-stage cell and genome engineering company that combines a novel patient engineering approach with targeted therapies to provide a single company solution for patients suffering from hematological malignancies. The Company’s proprietary platform leverages its expertise in hematopoietic stem cell (“HSC”) biology, genome engineering and targeted therapy development to genetically modify HSCs to remove surface targets expressed by cancer cells. The Company is headquartered in Cambridge, Massachusetts. The Company was incorporated on December 30, 2015 . Risks and Uncertainties The Company is subject to a number of risks common to development stage companies in the biotechnology industry, including, but not limited to, risks of failure of preclinical studies and clinical trials, dependence on key personnel, protection of proprietary technology, reliance on third party organizations, risks of obtaining regulatory approval for any product candidate that it may develop, development by competitors of technological innovations, compliance with government regulations, and the need to obtain additional financing. The Company anticipates that it will continue to incur significant operating losses for the next several years as it continues to develop its product candidates. The Company believes that its existing cash, cash equivalents and marketable securities at December 31, 2023 will be sufficient to allow the Company to fund its current operations through at least a period of one year after the date the financial statements are issued.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Certain comparative amounts have been reclassified to conform to the current period presentation. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) or an Accounting Standards Update (“ASU”) issued by the Financial Accounting Standards Board (“FASB”). Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the consolidated financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: accrued expenses and related research and development expenses. Segments Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on an aggregate basis for the purpose of allocating resources. Cash and Cash Equivalents The Company considers highly-liquid investments purchased with an original maturity date of ninety days or less from the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds. Cash equivalents are stated at cost, which approximates market value. Marketable Securities Investments in marketable debt securities are classified as available-for-sale. Marketable securities with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such securities represent an investment of cash that is available for current operations. Available-for-sale marketable securities are reported at fair value at each balance sheet date. Unrealized gains or losses are reported as a component of accumulated other comprehensive income (loss), a component of stockholders’ equity. Amortization and accretion of premiums and discounts are recorded in interest income. Realized gains and losses are included as a component of other income, net in the consolidated statements of operations. The Company evaluates its marketable securities with unrealized losses for impairment. When assessing marketable securities for unrealized declines in value, the Company considers whether the decline in value is related to a credit loss or non-credit loss. For credit losses, the Company reduces the marketable security to fair value through an allowance for credit losses recorded to the balance sheet and corresponding charge to the statement of operations. The allowance for credit losses and corresponding impairment charge is adjusted each period for changes in fair value. For non-credit losses, the Company reduces the marketable security to fair value through a charge to the statement of comprehensive income (loss), reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. No credit losses were recorded during the periods presented. Restricted Cash Equivalents The Company had $ 2.4 million of restricted cash equivalents in the form of a letter of credit related to a lease at December 31, 2023 and 2022 . Comprehensive income (loss) Comprehensive income (loss) includes net loss, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash equivalents and marketable securities. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company deposits its cash in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities may consist of money market funds and marketable debt securities, including corporate bonds and U.S. Treasury securities. The Company’s investment policy limits instruments to investment grade securities with high credit quality issuers with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. 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. Cloud Computing Arrangements The Company capitalizes implementation costs for cloud computing arrangement service contracts. The Company’s cloud computing arrangements relate to its enterprise resource planning and manufacturing software. For such cloud computing service contracts, the Company capitalizes certain implementation costs as prepaid expenses in the consolidated balance sheets. The Company amortizes these capitalized cloud computing implementation costs into general and administrative expenses using the straight-line method over the fixed, non-cancellable term of the associated hosting arrangement, plus any reasonably certain renewal periods. Property and Equipment, Net Property and equipment, net is recorded at cost less accumulated depreciation. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, which are as follows: Estimated Useful Life Computer equipment 3 years Manufacturing equipment 5 years Furniture and equipment 5 years Laboratory equipment 5 years Leasehold improvements Shorter of remaining lease term or useful life Purchased assets that are not yet in service are recorded to construction-in-process and no depreciation expense is recorded. Once they are placed in service, they are reclassified to the appropriate asset class. When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is reflected in the Company’s consolidated statements of operation and comprehensive loss. Expenditures for maintenance and repairs are expensed as incurred. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. The Company continually evaluates whether events or circumstances have occurred that indicate that the estimated remaining useful life of its long-lived assets may warrant revision or that the carrying value of these assets may not be recoverable. If circumstances require that a long-lived asset or asset group be tested for impairment, the Company first compares the estimated undiscounted future cash flows expected to result from the use or disposition of that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment loss would be recognized to the extent the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market prices and third-party independent appraisals, as considered necessary. No impairments occurred in the years ending December 31, 2023 and 2022. Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease. Leases with a term greater than one year are recognized on the consolidated balance sheet as a right-of-use (“ROU”) asset and current and non-current lease liabilities, as applicable. The Company has made an accounting policy election, known as the short-term lease recognition exemption, which allows the Company to not recognize ROU assets and lease liabilities that arise from short-term leases (12 months or less); The Company has applied this election to all classes of underlying assets. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to cancel a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew or will not cancel, respectively. The Company monitors its material leases on a quarterly basis. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of future lease payments over the expected remaining lease term. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. Certain adjustments to the ROU asset may be required for items such as lease prepayments or incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. The Company has elected to account for the lease and non-lease components together for office, laboratory, and manufacturing real estate leases. Research and Development Research and development expenses include costs directly attributable to the conduct of the Company’s research and development programs. Expenditures relating to research and development are expensed in the period incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. The cost of materials for a research and development activity that have an alternative future use is capitalized when the materials are acquired and recognized as expense as consumed. The costs of materials that were acquired for a particular research and development activity and have no alternative future use are expensed in the period acquired. Costs incurred in obtaining licenses are recognized as research and development expense as incurred if the license has no alternative use. Accrued Research and Development Expenses The Company has entered into various research and development related contracts, including contracts with third-party contract research organizations and contract manufacturing organizations. These agreements are cancelable, and related payments are recognized as research and development expenses as incurred. The Company records accrued liabilities for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes the progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. To date, the Company’s historical accrual estimates have not been materially different from the actual costs. Stock-Based Compensation Expense The Company accounts for stock-based compensation under the provisions of ASC 718-10, Compensation—Stock Compensation (“ASC 718-10”), which requires all share-based payments to employees, non-employees and directors, including grants of stock options and restricted stock, to be recognized in the consolidated statements of operations and comprehensive loss based on their fair values on the date of grant over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the ratable method. The Company classifies stock-based compensation expense in the same manner in which the award recipient’s payroll or service provider’s costs are classified. Share-based payments that contain performance conditions are recognized when such conditions are probable of being achieved. The fair value of each restricted common stock award and each restricted stock unit award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model which requires inputs based on certain subjective assumptions, including the following: • Fair Value of Common Stock — See the discussion below. • Expected Term —The expected term represents the period that the stock-based awards are expected to be outstanding. The Company uses the simplified method to determine the expected term, which is based on the average of the time-to-vesting and the contractual life of the options. • Expected Volatility —Because the Company does not have sufficient trading history for its common stock as of December 31, 2023, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in life cycle or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. • Risk-Free Interest Rate —The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the awards. • Dividend Yield —The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero . The Company began to use the closing common stock price as reported on the Nasdaq Global Select Market exchange as the fair value of common stock on the date of a grant subsequent to the Company's initial public offering of its common stock (“IPO”). Prior to the Company's IPO the estimated fair value of common stock was determined by the Company’s board of directors as of the date of each option grant, with input from management, considering third-party valuations of its common stock as well as the Company’s board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the grant. These objective and subjective factors include: (i) prices paid for the Company’s redeemable convertible preferred stock, and the rights, preferences, and privileges of the Company’s redeemable convertible preferred stock and common stock; (ii) the Company’s stage of development; (iii) the fact that the grants of stock-based awards related to illiquid securities in a private company; and (iv) the likelihood of achieving a liquidity event for the common stock underlying the stock-based awards, such as an initial public offering or sale of the Company, given prevailing market conditions. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately Held Company Equity Securities Issued as Compensation. Each valuation methodology includes estimates and assumptions that require the Company’s judgment. The methodology utilized to estimate the fair value of the Company’s common stock was the option-pricing method (“OPM”) to back-solve the estimated value of the Company’s equity and corresponding value of the Company’s common stock. Income Taxes The Company accounts for income taxes using the asset and liability approach. Deferred tax assets and liabilities represent future tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of assets and liabilities and for loss carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is established to reduce deferred tax assets to the amounts expected to be realized. The Company also recognizes a tax benefit from uncertain tax positions only if it is “more likely than not” that the position is sustainable based on its technical merits. The Company accounts for interest or penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has no t incurred interest and penalties related to uncertain tax positions. Should such costs be incurred, they would be classified as a component of provision for income taxes. Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the reporting period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common shares and potentially dilutive securities outstanding during the periods. For purposes of the diluted net loss per share calculation, restricted stock, restricted stock units and stock options considered to be potentially dilutive securities were excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all reporting periods presented. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected to take advantage of the extended transition period for complying with certain new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. Recently Issued Accounting Pronouncements Not Yet Adopted In October 2023, the FASB issued ASU 2023-06 Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”), which modifies certain disclosure and presentation requirements of a variety of Topics in the Codification and is intended to both clarify or improve such requirements and align the requirements with the SEC’s regulations. The effective date for each amendment is the effective date of the removal of the related disclosure from Regulation S-X or Regulation S-K, with early adoption prohibited. The Company will apply the provisions prospectively as such provisions become effective, and does not expect ASU 2023-06 to have a material impact on the consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 updates reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and information used to assess segment performance. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period, with early adoption permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires more detailed income tax disclosures, requiring entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. The disclosure requirements will be applied on a prospective basis, with the option to apply them retrospectively. This update is effective beginning with the Company’s 2025 fiscal year annual reporting period, with early adoption permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	3. Marketable Securities The amortized cost and estimated fair value of marketable securities, by contractual maturity are as follows: December 31, 2023 (in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Maturing in one year or less U.S. Treasury Bill $ 8,806 $ 6 $ — $ 8,812 U.S. Treasuries 97,086 12 ( 95 ) 97,003 Total $ 105,892 $ 18 $ ( 95 ) $ 105,815 December 31, 2022 (in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Maturing in one year or less Corporate Bonds $ 5,001 $ — $ ( 56 ) $ 4,945 U.S. Treasuries 116,432 — ( 617 ) 115,815 Maturing after one year through five years U.S. Treasuries 51,876 — ( 97 ) 51,779 Total $ 173,309 $ — $ ( 770 ) $ 172,539 The following table summarizes the fair value and gross unrealized losses aggregated by category and the length of time that individual securities have been in an unrealized loss position: December 31, 2023 Greater than twelve months Total (in thousands) Fair value Unrealized loss Fair value Unrealized loss U.S. Treasuries $ 53,447 $ ( 95 ) $ 53,447 $ ( 95 ) Total $ 53,447 $ ( 95 ) $ 53,447 $ ( 95 ) December 31, 2022 Greater than twelve months Total (in thousands) Fair value Unrealized loss Fair value Unrealized loss Corporate Bonds $ 4,945 $ ( 57 ) $ 4,945 $ ( 57 ) U.S. Treasuries 162,601 ( 713 ) 162,601 ( 713 ) Total $ 167,546 $ ( 770 ) $ 167,546 $ ( 770 ) The Company holds investment grade marketable securities considered to be in an unrealized loss position. Although these marketable securities are held at an unrealized loss position at December 31, 2023, the Company does not intend to sell the marketable securities prior to the value of the securities being recovered and the Company has concluded that it is more likely than not that the marketable securities cost basis values will be recovered prior to sale of the securities and that there are no conditions or events that might require the Company to sell the securities before recovery of the cost basis occurs. Further, the Company did no t record any impairments to marketable securities or reserves for credit losses related to its marketable debt securities during the periods ended December 31, 2023 and December 31, 2022.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis: December 31, 2023 (in thousands) Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 31,164 $ — $ — $ 31,164 Marketable securities U.S. Treasury Bill 8,812 — — 8,812 U.S. Treasuries — 97,003 — 97,003 Total marketable securities 8,812 97,003 — 105,815 Restricted cash equivalents Money market funds 2,413 — — 2,413 Total $ 42,389 $ 97,003 $ — $ 139,392 December 31, 2022 (in thousands) Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 46,981 $ — $ — $ 46,981 Marketable securities Corporate bonds — 4,945 — 4,945 U.S. Treasuries — 167,594 — 167,594 Total marketable securities — 172,539 — 172,539 Restricted cash equivalents Money market funds 2,413 — — 2,413 Total $ 49,394 $ 172,539 $ — $ 221,933 The fair value of the Company’s cash equivalents and restricted cash equivalents is based on quoted market prices in active markets with no valuation adjustment. The fair value of marketable securities was determined based on observable market inputs. During the years ended December 31, 2023 and 2022 , there were no transfers between levels. Prepaid expenses, accounts payable and accrued expenses are stated at their respective historical carrying values which approximate fair value due to their short-term nature.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net Property and equipment, net consisted of the following: December 31, December 31, (in thousands) 2023 2022 Laboratory equipment $ 10,028 $ 9,499 Manufacturing equipment 6,936 5,706 Computer equipment 432 432 Furniture, fixtures and other 599 568 Construction in progress 146 1,039 Total 18,141 17,244 Less: Accumulated depreciation ( 8,091 ) ( 4,610 ) Property and equipment, net $ 10,050 $ 12,634 Depreciation expense for the years ended December 31, 2023 and 2022 was approximately $ 3.5 million and $ 2.5 million, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: December 31, December 31, (in thousands) 2023 2022 Employee-related expenses $ 5,962 $ 4,408 Professional fees 1,245 1,701 Clinical expenses 1,495 532 Research and development expenses 1,059 569 Manufacturing expenses 842 328 Other 274 351 Total accrued liabilities $ 10,877 $ 7,889

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	7. Stockholders' Equity Common Stock As of December 31, 2023 and 2022 , the Company’s authorized capital stock included 400,000,000 shares of its $ 0.0001 par value common stock. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders provided, however, that, except as otherwise required by law, holders of common stock shall not be entitled to vote on any amendment to the Company’s Certificate of Incorporation, as amended (the “Certificate of Incorporation”), that relates solely to the terms of one or more outstanding series of preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to the Certificate of Incorporation or pursuant to the Delaware General Corporation Law. Common stockholders are entitled to receive dividends, as may be declared by the Company’s board of directors, if any, subject to the preferential dividend rights of the preferred stock. No dividends have been declared or paid as of and for either of the years ended December 31, 2023 and 2022. At-the-Market Sales During the years ended December 31, 2023 and, 2022, the Company sold 1,016,662 and 866,030 shares of common stock, respectively, in at-the-market offerings at a weighted average price per share of $ 4.75 and $ 5.25 , respectively, for aggregate net proceeds of $ 4.7 million and $ 4.4 million, respectively after deducting commissions. Offering and Concurrent Private Placement In December 2022, the Company issued 15,302,267 shares of commo n stock in an underwritten public offering at a price per share of $ 4.30 for proceeds of $ 61.3 million, after deducting underwriting discounts, commissions, and offering expenses payable by the Company. In a separate concurrent private placement, the Company sold 11,627,907 shares of common stock at a price of $ 4.30 per share to RA Capital Healthcare Fund, L.P. for proceeds of $ 49.5 million, after deducting related placement fees payable by the company.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	8. Stock-Based Compensation 2023 Inducement Plan On August 25, 2023, the Company’s board of directors adopted the Company’s 2023 Inducement Plan (the “2023 Inducement Plan”) pursuant to which the Company reserved 3,500,000 shares of common stock for issuance under the 2023 Inducement Plan. The 2023 Inducement Plan provides for the grant of non-statutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance awards and other forms of stock-based compensation to eligible individuals. In accordance with Nasdaq Marketplace Rule 5635(c)(4), awards under the 2023 Inducement Plan may only be made to individuals not previously employees or directors of the Company (or following such individuals’ bona fide period of non-employment with the Company), as an inducement material to the individuals’ entry into employment with the Company. Awards granted under the 2023 Inducement Plan must be approved by either a majority of the Company’s independent directors or the compensation committee of the Company’s board of directors. As of December 31, 2023, the Company had 3,263,436 shares of its common stock available for future issuance under the 2023 Inducement Plan. Stock Incentive Plans In December 2015, the Company’s board of directors adopted and approved the 2015 Stock Incentive Plan (as amended to date, the “2015 Plan”). The 2015 Plan provided for the granting of incentive stock options, non-statutory stock options, restricted stock awards and other stock-based awards to eligible employees, officers, directors, consultants and advisors as determined by the Company’s board of directors. In February 2021, the Company’s board of directors adopted and stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”). The 2021 Plan became effective on February 5, 2021, following which no further grants were or will be made under the 2015 Plan. The 2021 Plan provides for the grant of stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance stock awards and other forms of stock compensation to our employees, consultants and directors. The number of shares of our common stock reserved for issuance under our 2021 Plan will automatically increase on January 1 of each year through January 1, 2031, by 4.0 % of the total number of shares of common stock outstanding on December 31 of the preceding calendar year. Any grants that expire or are canceled, terminated, forfeited, fail to vest, or are withheld to satisfy a tax withholding obligation are allowed to be reissued under 2021 Plan. As of December 31, 2023, the Company had 1,270,867 shares of its common stock available for future issuance under the 2021 Plan. Stock Options The Company’s stock options generally vest over 48 months with 25 % vesting after one year followed by ratable monthly vesting over three years and have a contractual term of 10 years . The weighted-average assumptions used principally in determining the fair value of options granted were as follows: Year Ended December 31, 2023 2022 Fair value of common stock $ 4.94 $ 4.78 Expected term (in years) 6.0 5.9 Expected volatility 81.7 % 78.8 % Risk-free interest rate 3.8 % 2.5 % Dividend yield — — The following table summarizes the Company’s stock option activity for the year ended December 31, 2023: Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2022 6,471,524 $ 6.69 8.28 $ 14,949 Granted 2,347,469 4.94 Vested and exercised ( 94,028 ) 1.85 Forfeited ( 358,336 ) 7.41 Expired ( 76,552 ) 12.09 Outstanding at December 31, 2023 8,290,077 $ 6.17 7.71 $ 999 Exercisable at December 31, 2023 4,539,019 $ 6.19 7.02 $ 880 The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the respective date. The weighted-average grant-date fair value of stock options granted during the years ended December 31, 2023 and 2022 was $ 3.56 and $ 7.10 per share, respectively. As of December 31, 2023, total unrecognized compensation expense related to stock options was $ 14.0 million which is expected to be recognized over a weighted-average period of 2.3 years. The intrinsic value of stock options exercised was $ 0.1 million for the year ended December 31, 2023. As of December 31, 2023 and 2022, options for 10,299 and 83,459 shares with weighted average exercise prices of $ 4.90 and $ 2.23 were exercised and unvested, respectively. The underlying proceeds from the unvested exercises of less than $ 0.1 million and $ 0.2 million is recorded in other current liabilities as of December 31, 2023 and 2022, on the consolidated balance sheet. Restricted Stock Units As of December 31, 2023, there were 1,113,381 restricted stock units outstanding under the 2021 Plan and the 2023 Inducement Plan. The following table summarizes the Company's unvested restricted stock unit activity for the year ended December 31, 2023: Shares Weighted-Average Grant Date Fair Value Unvested at December 31, 2022 1,430,200 $ 5.49 Granted 801,611 4.88 Vested ( 1,019,846 ) 5.59 Forfeited ( 98,584 ) 5.71 Unvested at December 31, 2023 1,113,381 $ 4.94 As of December 31, 2023, total unrecognized compensation expense related to the unvested restricted stock units was $ 4.6 million, which is expected to be recognized over a weighted average period of 2.2 years. 2021 Employee Stock Purchase Plan In February 2021, the Company’s board of directors adopted and stockholders approved the 2021 Employee Stock Purchase Plan (the “ESPP”). The ESPP became effective on February 5, 2021. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1 of each year through January 1, 2031, by the lesser of (i) 1 % of the total number of shares of our common stock outstanding on December 31 of the preceding calendar year, and (ii) 1,800,000 shares. If purchase rights granted under the ESPP terminate without having been exercised, the shares of common stock not purchased under such purchase rights will again become available for issuance under the ESPP. As of December 31, 2023, the Company had 1,289,604 shares of its common stock available for future issuance under the ESPP. The ESPP permits eligible employees to purchase common stock through accumulated payroll deductions at a purchase price equal to 85 % of the lesser of the market value of the common stock at the beginning of the 6-month offering period or on the purchase date. During the years ended December 31, 2023 and 2022, the Company issued 82,703 and 34,242 shares with a weighted average purchase price of $ 2.73 and $ 3.41 during the year ended December 31, 2023, which resulted in an immaterial amount of compensation expense. Stock-Based Compensation Stock-based compensation expense was allocated as follows: Year Ended (in thousands) 2023 2022 Research and development $ 6,831 $ 6,036 General and administrative 6,531 4,659 Total stock-based compensation expense $ 13,362 $ 10,695

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	9. Leases Cambridgepark Lease In December 2019, the Company entered into a lease agreement for its new corporate office and laboratory facility (the “Cambridgepark Lease”) in Cambridge, Massachusetts. The Cambridgepark Lease has a term of 10 years , beginning on the rent commencement date which is two months after the lease commencement date. There are no options to extend the lease. The lease commencement date, for accounting purposes, was deemed to be reached as of June 30, 2020. On June 15, 2021, the Company entered into the first lease amendment (“First Lease Amendment”) and the second lease amendment (“Second Lease Amendment” and, together with the First Lease Amendment, the “Lease Amendments”) with PPF Off 100 Cambridge Park Drive, LLC (the “Landlord”). The Lease Amendments amended the Cambridgepark Lease with the Landlord in Cambridge, Massachusetts to add additional leased space in the same building (the “Amended Cambridgepark Lease”). The First Lease Amendment expanded the amount of space leased by the Company by an additional 10,262 square feet in exchange for aggregate total fixed rent payments of approximately $ 8.4 million with the annual fixed rental payments escalating from $ 0.8 million to $ 1.1 million during the term. The First Lease Amendment commenced for accounting purposes on January 28, 2022 . The Second Lease Amendment expands the amount of space leased by the Company by an additional 30,175 square feet in exchange for aggregate total fixed ren t payments of approximately $ 22.3 million with the annual fixed rental payments escalating from $ 1.1 million to $ 3.0 million during the term. The Second Lease Amendment’s term commenced for accounting purposes on April 29, 2022 . Payments associated with the Amended Cambridgepark Lease include fixed and variable payments. Variable payments relate to the Company’s share of the Landlord’s operating costs associated with the underlying assets and are recognized when the event on which those payments are assessed. The Amended Cambridgepark Lease does not contain a residual value guarantee. The Lease Amendments term end dates are coterminous with the Cambridgepark Lease. In conjunction with the Amended Cambridgepark Lease, the Company was required to establish a $ 2.4 million irrevocable standby letter of credit for the benefit of the Landlord, which has been secured by money market investments and is presented as restricted cash equivalents. The elements o f lease expense were as follows: Year Ended December 31, (in thousands) 2023 2022 Operating lease cost $ 7,802 $ 6,435 Variable lease cost 2,618 1,798 Total lease cost $ 10,420 $ 8,233 Amounts reported in the consolidated balance sheets and the weight-average lease term and discount rate information were as follows: (in thousands except weighted-average amounts) December 31, 2023 December 31, 2022 Assets Operating lease right-of-use assets $ 40,048 $ 44,444 Liabilities Operating lease liabilities, current $ 3,830 $ 3,272 Operating lease liabilities, non-current 31,830 35,640 Total lease liabilities $ 35,660 $ 38,912 Weighted-Average Lease Term and Discount Rate Weighted-average remaining lease term (years) 6.7 7.7 Weighted-average discount rate 8.2 % 8.2 % The following table represents other lease activity: Year Ended December 31, (in thousands) 2023 2022 Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 6,658 $ 13,311 Right-of-use assets obtained in exchange for lease obligations $ — $ 23,376 Future lease payments for noncancelable leases as of December 31, 2023 were as follows: (in thousands) December 31, 2023 2024 $ 6,591 2025 6,651 2026 6,681 2027 6,882 2028 7,088 Thereafter 12,902 Total lease payments $ 46,795 Less: imputed interest ( 11,135 ) Present value of lease liabilities $ 35,660

Significant Agreements

Significant Agreements	12 Months Ended
	Dec. 31, 2023
Significant Agreements [Abstract]
Significant Agreements	10. Significant Agreements The Company has agreements with third parties in the normal course of business under which it has obtained licenses for certain developed technologies. Such arrangements may require ongoing payments including annual fees and payments upon the achievement of various development, clinical, regulatory, and commercial milestones. In addition, if any products related to these agreements are approved for sale, the Company may be required to pay significant milestones upon approval and milestones and/or royalties on future sales. The payment of these amounts, however, is contingent upon the occurrence of various future events, which have a high degree of uncertainty of occurrence.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies Legal Proceedings The Company is not currently a party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or potential range of loss is probable and reasonably estimated under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company recognizes expenses for its costs related to its legal proceedings, as incurred.

Defined Contribution Benefit Pl

Defined Contribution Benefit Plan	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Defined Contribution Benefit Plan	12. Defined Contribution Benefit Plan The Company maintains a defined contribution plan under Section 401(k) (the “401(k) Plan”) of the Internal Revenue Code, as amended (the “Code”). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis, as well as Roth post tax deferrals. The Company matches 100 % of compensation amounts deferred up to the first 1 % of an employee's compensation plus 50 % of compensation amounts deferred between 1 % and 6 % of an employee's compensation. All matching contributions are immediately vested. Expense recognized by the Company for matching contributions made in accordance with the 401(k) Plan was $ 1.0 million and $ 0.8 million for the years ended December 31, 2023 and December 31, 2022 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The Company accounts for income taxes under FASB ASC 740 (“ASC 740”). For the years ended December 31, 2023 and 2022 , the Company did not record a current or deferred income tax expense or benefit. The following table reconciles the federal statutory income rate to the Company’s effective income tax rate: Year Ended December 31, 2023 2022 Federal income tax rate 21.0 % 21.0 % State income tax benefit 6.1 % 5.8 % Permanent items ( 0.9 ) % ( 0.4 ) % Research tax credits 5.7 % 5.5 % Other ( 0.4 ) % ( 0.4 ) % Valuation allowance ( 31.5 ) % ( 31.5 ) % Effective income tax rate — — Deferred tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carryforwards and temporary differences between the carrying amount of assets and liabilities for financial reporting and the amounts used for tax purposes. Significant components of the Company’s deferred tax assets and liabilities were as follows: December 31, (in thousands) 2023 2022 Deferred tax assets: Accrued expenses $ 1,428 $ 1,224 Federal net operating loss carryforwards 39,934 32,262 State net operating loss carryforwards 11,423 8,919 Tax credits 17,062 10,712 Stock compensation 1,545 1,248 R&D Capitalization 33,503 14,881 Amortization 1,464 429 Lease liability 9,746 10,445 Total deferred tax assets 116,105 80,120 Valuation allowance ( 104,403 ) ( 68,348 ) Net total deferred tax assets $ 11,702 $ 11,772 Deferred tax liabilities: Lease right of use asset ( 10,945 ) ( 11,951 ) Depreciation and amortization ( 757 ) 179 Total deferred tax liabilities $ ( 11,702 ) $ ( 11,772 ) Net deferred tax assets $ — $ — The Company has weighed the positive and negative evidence to assess the recoverability of its deferred tax assets. Realization of future tax benefits is dependent on many factors, including the Company’s ability to generate taxable income. After this assessment, the Company determined it was more likely than not that the Company will not realize the benefit of its deferred tax assets. As a result, the Company has provided a full valuation allowance against its net deferred tax assets. The valuation allowance for deferred tax assets as of December 31, 2023 and 2022 was $ 104.4 million and $ 68.3 million , respectively. For the years ended December 31, 2023 and 2022, the Company recorded an increase in the valuation allowance of $ 36.1 million and $ 28.9 million, respectively, primarily related to net operating losses incurred by the Company. As of December 31, 2023, the Company had gross U.S. federal net operating loss carryforwards of $ 190.2 million including $ 188.3 million that had an indefinite carryforward period and $ 1.9 million that were subject to expiration at various dates through 2037 . As of December 31, 2023, the Company had state net operating loss carryforwards of $ 180.8 million which will expire at various dates through 2043 . As of December 31, 2023, the Company had U.S. federal research and development tax credit carryforwards of $ 12.2 million which will expire at various dates through 2042 and state research and credit carryforwards of $ 6.1 million which will expire at various dates through 2038 . The net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50 %, as defined under Sections 382 and 383 of the Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has not determined whether an ownership change has occurred and as such, the Company’s net operating losses may be limited. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research development credit carryforwards before utilization. The Company has not, as yet, conducted a study of research and development credit carryforwards. Such a study, once undertaken by the Company, may result in an adjustment to the research and development credit carryforwards. However, a full valuation allowance has been provided against the Company’s research and development credits and, if any adjustment is required, such adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the balance sheet or statement of operations if any adjustment is required. As of December 31, 2023 and 2022 , the Company did no t have any unrecognized tax benefits. Any future interest and penalties related to income tax matters would be recognized in the provision for income tax. As of December 31, 2023 and 2022 , the Company did no t have a balance of accrued interest and penalties related to uncertain tax positions. The Company files income tax returns in the United States and various states. As of December 31, 2023 , there were no income tax examinations in progress . The tax years 2020 through present remain open to examination by major taxing jurisdictions to which the Company is subject, which are primarily in the United States. In addition, tax years prior to 2019 resulted in losses and the Company also generated research and development tax credits during those years. Since carryforward attributes generated in these years may be utilized in future years, years prior to 2019 may still be adjusted upon examination by the Internal Revenue Service or state tax authorities if they have or will be used in a future period.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	14. Net Loss Per Share The following table sets forth the computation of the Company’s basic and diluted net loss per share for the years ended December 31, 2023 and 2022: Year Ended (in thousands, except share and per share amounts) 2023 2022 Numerator: Net loss attributable to common stockholders $ ( 117,863 ) $ ( 92,094 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 67,191,973 39,551,420 Net loss per share attributable to common stockholders, basic and diluted $ ( 1.75 ) $ ( 2.33 ) The Company’s potentially dilutive securities were stock options, unvested restricted stock, and restricted stock units. Based on the amounts outstanding at December 31, 2023 and 2022, the Company excluded the following potential common shares from the computation of diluted net loss per share because including them would have had an anti-dilutive effect: As of December 31, 2023 2022 Options to purchase common stock 8,290,077 6,388,065 Unvested restricted stock 10,299 83,459 Restricted stock units 1,113,381 1,430,200

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Certain comparative amounts have been reclassified to conform to the current period presentation. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) or an Accounting Standards Update (“ASU”) issued by the Financial Accounting Standards Board (“FASB”).
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the consolidated financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: accrued expenses and related research and development expenses.
Segments	Segments Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on an aggregate basis for the purpose of allocating resources.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers highly-liquid investments purchased with an original maturity date of ninety days or less from the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds. Cash equivalents are stated at cost, which approximates market value.
Marketable Securities	Marketable Securities Investments in marketable debt securities are classified as available-for-sale. Marketable securities with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such securities represent an investment of cash that is available for current operations. Available-for-sale marketable securities are reported at fair value at each balance sheet date. Unrealized gains or losses are reported as a component of accumulated other comprehensive income (loss), a component of stockholders’ equity. Amortization and accretion of premiums and discounts are recorded in interest income. Realized gains and losses are included as a component of other income, net in the consolidated statements of operations. The Company evaluates its marketable securities with unrealized losses for impairment. When assessing marketable securities for unrealized declines in value, the Company considers whether the decline in value is related to a credit loss or non-credit loss. For credit losses, the Company reduces the marketable security to fair value through an allowance for credit losses recorded to the balance sheet and corresponding charge to the statement of operations. The allowance for credit losses and corresponding impairment charge is adjusted each period for changes in fair value. For non-credit losses, the Company reduces the marketable security to fair value through a charge to the statement of comprehensive income (loss), reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. No credit losses were recorded during the periods presented.
Restricted Cash Equivalents	Restricted Cash Equivalents The Company had $ 2.4 million of restricted cash equivalents in the form of a letter of credit related to a lease at December 31, 2023 and 2022 .
Comprehensive income (loss)	Comprehensive income (loss) Comprehensive income (loss) includes net loss, as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash equivalents and marketable securities. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company deposits its cash in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s marketable securities may consist of money market funds and marketable debt securities, including corporate bonds and U.S. Treasury securities. The Company’s investment policy limits instruments to investment grade securities with high credit quality issuers with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. 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.
Cloud Computing Arrangements	Cloud Computing Arrangements The Company capitalizes implementation costs for cloud computing arrangement service contracts. The Company’s cloud computing arrangements relate to its enterprise resource planning and manufacturing software. For such cloud computing service contracts, the Company capitalizes certain implementation costs as prepaid expenses in the consolidated balance sheets. The Company amortizes these capitalized cloud computing implementation costs into general and administrative expenses using the straight-line method over the fixed, non-cancellable term of the associated hosting arrangement, plus any reasonably certain renewal periods.
Property and Equipment, Net	Property and Equipment, Net Property and equipment, net is recorded at cost less accumulated depreciation. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, which are as follows: Estimated Useful Life Computer equipment 3 years Manufacturing equipment 5 years Furniture and equipment 5 years Laboratory equipment 5 years Leasehold improvements Shorter of remaining lease term or useful life Purchased assets that are not yet in service are recorded to construction-in-process and no depreciation expense is recorded. Once they are placed in service, they are reclassified to the appropriate asset class. When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is reflected in the Company’s consolidated statements of operation and comprehensive loss. Expenditures for maintenance and repairs are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. The Company continually evaluates whether events or circumstances have occurred that indicate that the estimated remaining useful life of its long-lived assets may warrant revision or that the carrying value of these assets may not be recoverable. If circumstances require that a long-lived asset or asset group be tested for impairment, the Company first compares the estimated undiscounted future cash flows expected to result from the use or disposition of that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment loss would be recognized to the extent the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market prices and third-party independent appraisals, as considered necessary. No impairments occurred in the years ending December 31, 2023 and 2022.
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease. Leases with a term greater than one year are recognized on the consolidated balance sheet as a right-of-use (“ROU”) asset and current and non-current lease liabilities, as applicable. The Company has made an accounting policy election, known as the short-term lease recognition exemption, which allows the Company to not recognize ROU assets and lease liabilities that arise from short-term leases (12 months or less); The Company has applied this election to all classes of underlying assets. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to cancel a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew or will not cancel, respectively. The Company monitors its material leases on a quarterly basis. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of future lease payments over the expected remaining lease term. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. Certain adjustments to the ROU asset may be required for items such as lease prepayments or incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. The Company has elected to account for the lease and non-lease components together for office, laboratory, and manufacturing real estate leases.
Research and Development	Research and Development Research and development expenses include costs directly attributable to the conduct of the Company’s research and development programs. Expenditures relating to research and development are expensed in the period incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. The cost of materials for a research and development activity that have an alternative future use is capitalized when the materials are acquired and recognized as expense as consumed. The costs of materials that were acquired for a particular research and development activity and have no alternative future use are expensed in the period acquired. Costs incurred in obtaining licenses are recognized as research and development expense as incurred if the license has no alternative use.
Accrued Research and Development Expenses	Accrued Research and Development Expenses The Company has entered into various research and development related contracts, including contracts with third-party contract research organizations and contract manufacturing organizations. These agreements are cancelable, and related payments are recognized as research and development expenses as incurred. The Company records accrued liabilities for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes the progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. To date, the Company’s historical accrual estimates have not been materially different from the actual costs.
Stock-Based Compensation Expense	Stock-Based Compensation Expense The Company accounts for stock-based compensation under the provisions of ASC 718-10, Compensation—Stock Compensation (“ASC 718-10”), which requires all share-based payments to employees, non-employees and directors, including grants of stock options and restricted stock, to be recognized in the consolidated statements of operations and comprehensive loss based on their fair values on the date of grant over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the ratable method. The Company classifies stock-based compensation expense in the same manner in which the award recipient’s payroll or service provider’s costs are classified. Share-based payments that contain performance conditions are recognized when such conditions are probable of being achieved. The fair value of each restricted common stock award and each restricted stock unit award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model which requires inputs based on certain subjective assumptions, including the following: • Fair Value of Common Stock — See the discussion below. • Expected Term —The expected term represents the period that the stock-based awards are expected to be outstanding. The Company uses the simplified method to determine the expected term, which is based on the average of the time-to-vesting and the contractual life of the options. • Expected Volatility —Because the Company does not have sufficient trading history for its common stock as of December 31, 2023, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in life cycle or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. • Risk-Free Interest Rate —The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the awards. • Dividend Yield —The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero . The Company began to use the closing common stock price as reported on the Nasdaq Global Select Market exchange as the fair value of common stock on the date of a grant subsequent to the Company's initial public offering of its common stock (“IPO”). Prior to the Company's IPO the estimated fair value of common stock was determined by the Company’s board of directors as of the date of each option grant, with input from management, considering third-party valuations of its common stock as well as the Company’s board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the grant. These objective and subjective factors include: (i) prices paid for the Company’s redeemable convertible preferred stock, and the rights, preferences, and privileges of the Company’s redeemable convertible preferred stock and common stock; (ii) the Company’s stage of development; (iii) the fact that the grants of stock-based awards related to illiquid securities in a private company; and (iv) the likelihood of achieving a liquidity event for the common stock underlying the stock-based awards, such as an initial public offering or sale of the Company, given prevailing market conditions. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately Held Company Equity Securities Issued as Compensation. Each valuation methodology includes estimates and assumptions that require the Company’s judgment. The methodology utilized to estimate the fair value of the Company’s common stock was the option-pricing method (“OPM”) to back-solve the estimated value of the Company’s equity and corresponding value of the Company’s common stock.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability approach. Deferred tax assets and liabilities represent future tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of assets and liabilities and for loss carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is established to reduce deferred tax assets to the amounts expected to be realized. The Company also recognizes a tax benefit from uncertain tax positions only if it is “more likely than not” that the position is sustainable based on its technical merits. The Company accounts for interest or penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has no t incurred interest and penalties related to uncertain tax positions. Should such costs be incurred, they would be classified as a component of provision for income taxes.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding during the reporting period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common shares and potentially dilutive securities outstanding during the periods. For purposes of the diluted net loss per share calculation, restricted stock, restricted stock units and stock options considered to be potentially dilutive securities were excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all reporting periods presented.
Recent Accounting Pronouncements and Recently Adopted Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected to take advantage of the extended transition period for complying with certain new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. Recently Issued Accounting Pronouncements Not Yet Adopted In October 2023, the FASB issued ASU 2023-06 Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”), which modifies certain disclosure and presentation requirements of a variety of Topics in the Codification and is intended to both clarify or improve such requirements and align the requirements with the SEC’s regulations. The effective date for each amendment is the effective date of the removal of the related disclosure from Regulation S-X or Regulation S-K, with early adoption prohibited. The Company will apply the provisions prospectively as such provisions become effective, and does not expect ASU 2023-06 to have a material impact on the consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 updates reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and information used to assess segment performance. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period, with early adoption permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires more detailed income tax disclosures, requiring entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. The disclosure requirements will be applied on a prospective basis, with the option to apply them retrospectively. This update is effective beginning with the Company’s 2025 fiscal year annual reporting period, with early adoption permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Estimated Useful Life of Property and Equipment	Property and equipment, net is recorded at cost less accumulated depreciation. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, which are as follows: Estimated Useful Life Computer equipment 3 years Manufacturing equipment 5 years Furniture and equipment 5 years Laboratory equipment 5 years Leasehold improvements Shorter of remaining lease term or useful life

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity	The amortized cost and estimated fair value of marketable securities, by contractual maturity are as follows: December 31, 2023 (in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Maturing in one year or less U.S. Treasury Bill $ 8,806 $ 6 $ — $ 8,812 U.S. Treasuries 97,086 12 ( 95 ) 97,003 Total $ 105,892 $ 18 $ ( 95 ) $ 105,815 December 31, 2022 (in thousands) Amortized Cost Gross Unrealized Holding Gains Gross Unrealized Holding Losses Fair Value Maturing in one year or less Corporate Bonds $ 5,001 $ — $ ( 56 ) $ 4,945 U.S. Treasuries 116,432 — ( 617 ) 115,815 Maturing after one year through five years U.S. Treasuries 51,876 — ( 97 ) 51,779 Total $ 173,309 $ — $ ( 770 ) $ 172,539
Summary of Fair Value and Gross Unrealized Losses of Marketable Securities	The following table summarizes the fair value and gross unrealized losses aggregated by category and the length of time that individual securities have been in an unrealized loss position: December 31, 2023 Greater than twelve months Total (in thousands) Fair value Unrealized loss Fair value Unrealized loss U.S. Treasuries $ 53,447 $ ( 95 ) $ 53,447 $ ( 95 ) Total $ 53,447 $ ( 95 ) $ 53,447 $ ( 95 ) December 31, 2022 Greater than twelve months Total (in thousands) Fair value Unrealized loss Fair value Unrealized loss Corporate Bonds $ 4,945 $ ( 57 ) $ 4,945 $ ( 57 ) U.S. Treasuries 162,601 ( 713 ) 162,601 ( 713 ) Total $ 167,546 $ ( 770 ) $ 167,546 $ ( 770 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis: December 31, 2023 (in thousands) Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 31,164 $ — $ — $ 31,164 Marketable securities U.S. Treasury Bill 8,812 — — 8,812 U.S. Treasuries — 97,003 — 97,003 Total marketable securities 8,812 97,003 — 105,815 Restricted cash equivalents Money market funds 2,413 — — 2,413 Total $ 42,389 $ 97,003 $ — $ 139,392 December 31, 2022 (in thousands) Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 46,981 $ — $ — $ 46,981 Marketable securities Corporate bonds — 4,945 — 4,945 U.S. Treasuries — 167,594 — 167,594 Total marketable securities — 172,539 — 172,539 Restricted cash equivalents Money market funds 2,413 — — 2,413 Total $ 49,394 $ 172,539 $ — $ 221,933

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	Property and equipment, net consisted of the following: December 31, December 31, (in thousands) 2023 2022 Laboratory equipment $ 10,028 $ 9,499 Manufacturing equipment 6,936 5,706 Computer equipment 432 432 Furniture, fixtures and other 599 568 Construction in progress 146 1,039 Total 18,141 17,244 Less: Accumulated depreciation ( 8,091 ) ( 4,610 ) Property and equipment, net $ 10,050 $ 12,634

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: December 31, December 31, (in thousands) 2023 2022 Employee-related expenses $ 5,962 $ 4,408 Professional fees 1,245 1,701 Clinical expenses 1,495 532 Research and development expenses 1,059 569 Manufacturing expenses 842 328 Other 274 351 Total accrued liabilities $ 10,877 $ 7,889

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Weighted-Average Assumptions Used Principally in Determining Fair Value of Options Granted	The weighted-average assumptions used principally in determining the fair value of options granted were as follows: Year Ended December 31, 2023 2022 Fair value of common stock $ 4.94 $ 4.78 Expected term (in years) 6.0 5.9 Expected volatility 81.7 % 78.8 % Risk-free interest rate 3.8 % 2.5 % Dividend yield — —
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity for the year ended December 31, 2023: Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2022 6,471,524 $ 6.69 8.28 $ 14,949 Granted 2,347,469 4.94 Vested and exercised ( 94,028 ) 1.85 Forfeited ( 358,336 ) 7.41 Expired ( 76,552 ) 12.09 Outstanding at December 31, 2023 8,290,077 $ 6.17 7.71 $ 999 Exercisable at December 31, 2023 4,539,019 $ 6.19 7.02 $ 880
Summary of Unvested Restricted Stock Units Activity	The following table summarizes the Company's unvested restricted stock unit activity for the year ended December 31, 2023: Shares Weighted-Average Grant Date Fair Value Unvested at December 31, 2022 1,430,200 $ 5.49 Granted 801,611 4.88 Vested ( 1,019,846 ) 5.59 Forfeited ( 98,584 ) 5.71 Unvested at December 31, 2023 1,113,381 $ 4.94
Summary of Stock-Based Compensation Expense	Stock-based compensation expense was allocated as follows: Year Ended (in thousands) 2023 2022 Research and development $ 6,831 $ 6,036 General and administrative 6,531 4,659 Total stock-based compensation expense $ 13,362 $ 10,695

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Summary of Lease Expense	The elements o f lease expense were as follows: Year Ended December 31, (in thousands) 2023 2022 Operating lease cost $ 7,802 $ 6,435 Variable lease cost 2,618 1,798 Total lease cost $ 10,420 $ 8,233
Summary of Amounts Reported in Consolidated Balance Sheets and Weight-average Lease Term and Discount Rate Information	Amounts reported in the consolidated balance sheets and the weight-average lease term and discount rate information were as follows: (in thousands except weighted-average amounts) December 31, 2023 December 31, 2022 Assets Operating lease right-of-use assets $ 40,048 $ 44,444 Liabilities Operating lease liabilities, current $ 3,830 $ 3,272 Operating lease liabilities, non-current 31,830 35,640 Total lease liabilities $ 35,660 $ 38,912 Weighted-Average Lease Term and Discount Rate Weighted-average remaining lease term (years) 6.7 7.7 Weighted-average discount rate 8.2 % 8.2 %
Summary of Other Lease Activity	The following table represents other lease activity: Year Ended December 31, (in thousands) 2023 2022 Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 6,658 $ 13,311 Right-of-use assets obtained in exchange for lease obligations $ — $ 23,376
Summary of Future Lease Payments for Noncancelable Leases	Future lease payments for noncancelable leases as of December 31, 2023 were as follows: (in thousands) December 31, 2023 2024 $ 6,591 2025 6,651 2026 6,681 2027 6,882 2028 7,088 Thereafter 12,902 Total lease payments $ 46,795 Less: imputed interest ( 11,135 ) Present value of lease liabilities $ 35,660

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Federal Statutory Income Rate to Effective Income Tax Rate	The following table reconciles the federal statutory income rate to the Company’s effective income tax rate: Year Ended December 31, 2023 2022 Federal income tax rate 21.0 % 21.0 % State income tax benefit 6.1 % 5.8 % Permanent items ( 0.9 ) % ( 0.4 ) % Research tax credits 5.7 % 5.5 % Other ( 0.4 ) % ( 0.4 ) % Valuation allowance ( 31.5 ) % ( 31.5 ) % Effective income tax rate — —
Schedule of Significant Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities were as follows: December 31, (in thousands) 2023 2022 Deferred tax assets: Accrued expenses $ 1,428 $ 1,224 Federal net operating loss carryforwards 39,934 32,262 State net operating loss carryforwards 11,423 8,919 Tax credits 17,062 10,712 Stock compensation 1,545 1,248 R&D Capitalization 33,503 14,881 Amortization 1,464 429 Lease liability 9,746 10,445 Total deferred tax assets 116,105 80,120 Valuation allowance ( 104,403 ) ( 68,348 ) Net total deferred tax assets $ 11,702 $ 11,772 Deferred tax liabilities: Lease right of use asset ( 10,945 ) ( 11,951 ) Depreciation and amortization ( 757 ) 179 Total deferred tax liabilities $ ( 11,702 ) $ ( 11,772 ) Net deferred tax assets $ — $ —

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table sets forth the computation of the Company’s basic and diluted net loss per share for the years ended December 31, 2023 and 2022: Year Ended (in thousands, except share and per share amounts) 2023 2022 Numerator: Net loss attributable to common stockholders $ ( 117,863 ) $ ( 92,094 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 67,191,973 39,551,420 Net loss per share attributable to common stockholders, basic and diluted $ ( 1.75 ) $ ( 2.33 )
Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The Company’s potentially dilutive securities were stock options, unvested restricted stock, and restricted stock units. Based on the amounts outstanding at December 31, 2023 and 2022, the Company excluded the following potential common shares from the computation of diluted net loss per share because including them would have had an anti-dilutive effect: As of December 31, 2023 2022 Options to purchase common stock 8,290,077 6,388,065 Unvested restricted stock 10,299 83,459 Restricted stock units 1,113,381 1,430,200

Nature of the Business - Additi

Nature of the Business - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023
Nature Of Business [Line Items]
Incorporation date	Dec. 30, 2015

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of operating segment | Segment	1
Restricted cash equivalents	$ 2,413,000	$ 2,413,000
Impairment, Long-Lived Asset	$ 0	$ 0
Expected dividend yield	0%
Interest and penalties related to uncertain tax positions	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Estimated Useful Life of Property and Equipment (Details)	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	Leasehold Improvements
Computer Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Manufacturing Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years

Marketable Securities - Summary

Marketable Securities - Summary of Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 105,892	$ 173,309
Gross Unrealized Holding Gains	18
Gross Unrealized Holding losses	(95)	(770)
Fair Value	105,815	172,539
Maturing in One Year or Less | Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		5,001
Gross Unrealized Holding losses		(56)
Fair Value		4,945
Maturing in One Year or Less | U.S. Treasury Bill
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	8,806
Gross Unrealized Holding Gains	6
Fair Value	8,812
Maturing in One Year or Less | U.S. Treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	97,086	116,432
Gross Unrealized Holding Gains	12
Gross Unrealized Holding losses	(95)	(617)
Fair Value	$ 97,003	115,815
Maturing after One Year through Five Years | U.S. Treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		51,876
Gross Unrealized Holding losses		(97)
Fair Value		$ 51,779

Marketable Securities - Summa_2

Marketable Securities - Summary of Fair Value and Gross Unrealized Losses of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Fair value	$ 53,447	$ 167,546
Unrealized loss	(95)	(770)
Total Fair value	53,447	167,546
Total Unrealized loss	(95)	(770)
U.S. Treasuries
Debt Securities, Available-for-Sale [Line Items]
Fair value	53,447	162,601
Unrealized loss	(95)	(713)
Total Fair value	53,447	162,601
Total Unrealized loss	$ (95)	(713)
Corporate Bonds
Debt Securities, Available-for-Sale [Line Items]
Fair value		4,945
Unrealized loss		(57)
Total Fair value		4,945
Total Unrealized loss		$ (57)

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Credit losses related to marketable securities	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 139,392	$ 221,933
Marketable Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	105,815	172,539
Marketable Securities | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		4,945
Marketable Securities | U.S. Treasury Bill
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	8,812
Marketable Securities | U.S. Treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	97,003	167,594
Cash Equivalents | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	31,164	46,981
Restricted Cash Equivalents | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,413	2,413
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	42,389	49,394
Level 1 | Marketable Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	8,812
Level 1 | Marketable Securities | U.S. Treasury Bill
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	8,812
Level 1 | Cash Equivalents | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	31,164	46,981
Level 1 | Restricted Cash Equivalents | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	2,413	2,413
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	97,003	172,539
Level 2 | Marketable Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	97,003	172,539
Level 2 | Marketable Securities | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		4,945
Level 2 | Marketable Securities | U.S. Treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 97,003	$ 167,594

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value assets, level 1 to level 2 transfers amount	$ 0	$ 0
Fair value assets, level 2 to level 1 transfers amount	0	0
Fair value assets, transfers into level 3	0	0
Fair value assets, transfers out of level 3	$ 0	$ 0

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total	$ 18,141	$ 17,244
Less: Accumulated depreciation	(8,091)	(4,610)
Property and equipment, net	10,050	12,634
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total	10,028	9,499
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Total	6,936	5,706
Computer Equipment
Property Plant And Equipment [Line Items]
Total	432	432
Furniture, Fixtures and Other
Property Plant And Equipment [Line Items]
Total	599	568
Construction in Progress
Property Plant And Equipment [Line Items]
Total	$ 146	$ 1,039

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 3,492	$ 2,525

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Employee-related expenses	$ 5,962	$ 4,408
Professional fees	1,245	1,701
Clinical expenses	1,495	532
Research and development expenses	1,059	569
Manufacturing expenses	842	328
Other	274	351
Total accrued liabilities	$ 10,877	$ 7,889

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) Vote $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Class of Stock [Line Items]
Common stock, shares authorized | shares	400,000,000	400,000,000
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Common stock voting rights	Each share of common stock entitles the holder to one vote
Number of common stock voting rights | Vote	1
Dividends declared	$ 0	$ 0
Dividends paid	0	0
Aggregate net proceeds	$ 4,578,000	$ 4,451,000
Common stock, shares issued | shares	67,901,610	66,079,597
IPO
Class of Stock [Line Items]
Aggregate net proceeds		$ 61,300,000
Common stock, shares issued | shares		15,302,267
Common stock issued price per share | $ / shares		$ 4.3
Concurrent Private Placement
Class of Stock [Line Items]
Aggregate net proceeds		$ 49,500,000
Common stock issued price per share | $ / shares		$ 4.3
At-the-Market Sales
Class of Stock [Line Items]
Aggregate net proceeds	$ 4,700,000	$ 4,400,000
Common stock shares sold | shares	1,016,662	866,030
Weighted Average Price Per Share | $ / shares	$ 4.75	$ 5.25
Common Stock | Concurrent Private Placement
Class of Stock [Line Items]
Common stock shares sold | shares		11,627,907

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 05, 2021	Dec. 31, 2023	Dec. 31, 2022	Aug. 25, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant-date fair value of stock options granted		$ 3.56	$ 7.10
Unrecognized compensation expense related to stock options		$ 14
Unrecognized share based compensation expense, recognition period		2 years 3 months 18 days
Intrinsic value of stock options exercised		$ 0.1
Number unvested options		10,299	83,459
Weighted average exercise price of options exercised and unvested		$ 4.90	$ 2.23
Proceeds from unvested options exercises			$ 0.2
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from unvested options exercises		$ 0.1
Employee Stock Purchase Plan 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance increase percentage of total number of shares of common stock outstanding	1%
SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent	85%
Number of common stock reserved for issuance	1,800,000
Number of shares issued		82,703	34,242
Weighted average purchase price		$ 2.73	$ 3.41
Employee Stock Purchase Plan 2021 | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance		1,289,604
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting rights description		vest over 48 months with 25% vesting after one year followed by ratable monthly vesting over three years
Vesting period		48 months
Contractual term		10 years
Weighted-average grant-date fair value of stock options granted		$ 4.94	$ 4.78
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to related to restricted stock units		$ 4.6
Unrecognized share based compensation expense, recognition period		2 years 2 months 12 days
Number of units outstanding		1,113,381	1,430,200
Tranche One | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		1 year
Vesting percentage		25%
Tranche Two | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	0
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance		1,270,867
Shares reserved for issuance increase percentage of total number of shares of common stock outstanding	4%
2021 Plan | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of units outstanding		1,113,381
2023 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance		3,263,436		3,500,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Weighted-Average Assumptions Used Principally in Determining Fair Value of Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of common stock	$ 3.56	$ 7.10
Dividend yield	0%
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of common stock	$ 4.94	$ 4.78
Expected term (in years)	6 years	5 years 10 months 24 days
Expected volatility	81.70%	78.80%
Risk-free interest rate	3.80%	2.50%
Dividend yield	0%	0%

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding at December 31, 2022	6,471,524
Shares, Granted	2,347,469
Shares, Vested and exercised	(94,028)
Shares, Forfeited	(358,336)
Shares, Expired	(76,552)
Shares, Outstanding at December 31, 2023	8,290,077	6,471,524
Shares, Exercisable at December 31, 2023	4,539,019
Weighted-Average Exercise Price, Outstanding at December 31, 2022	$ 6.69
Weighted-Average Exercise Price, Granted	4.94
Weighted-Average Exercise Price, Vested and exercised	1.85
Weighted-Average Exercise Price, Forfeited	7.41
Weighted-Average Exercise Price, Expired	12.09
Weighted-Average Exercise Price, Outstanding at December 31, 2023	6.17	$ 6.69
Weighted-Average Exercise Price, Exercisable at December 31, 2023	$ 6.19
Weighted-Average Remaining Contractual Term, Outstanding	7 years 8 months 15 days	8 years 3 months 10 days
Weighted-Average Remaining Contractual Term, Exercisable at December 31, 2023	7 years 7 days
Aggregate Intrinsic Value, Outstanding	$ 999	$ 14,949
Aggregate Intrinsic Value, Exercisable at December 31, 20223	$ 880

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Unvested Restricted Stock Units Activity (Details) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Unvested at December 31, 2022 | shares	1,430,200
Shares, Granted | shares	801,611
Shares, Vested | shares	(1,019,846)
Shares, Forfeited | shares	(98,584)
Shares, Unvested at December 31, 2023 | shares	1,113,381
Weighted Average Grant Date Fair Value, Unvested at December 31, 2022 | $ / shares	$ 5.49
Weighted Average Grant Date Fair Value, Granted | $ / shares	4.88
Weighted Average Grant Date Fair Value, Vested | $ / shares	5.59
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	5.71
Weighted Average Grant Date Fair Value, Unvested at December 31, 2023 | $ / shares	$ 4.94

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 13,362	$ 10,695
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	6,831	6,036
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 6,531	$ 4,659

Leases - Additional Information

Leases - Additional Information (Details) $ in Millions			12 Months Ended
	Apr. 29, 2022 USD ($) ft²	Jan. 28, 2022 USD ($) ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2019
Standby Letters of Credit
Lessee Lease Description [Line Items]
Increase in irrevocable line of credit facility			$ 2.4
First Lease Amendment
Lessee Lease Description [Line Items]
Additional space leased | ft²		10,262
Aggregate total fixed rent payments		$ 8.4
Operating lease commencement date		Jan. 28, 2022
Second Lease Amendment
Lessee Lease Description [Line Items]
Additional space leased | ft²	30,175
Aggregate total fixed rent payments	$ 22.3
Operating lease commencement date	Apr. 29, 2022
Cambridgepark Lease
Lessee Lease Description [Line Items]
Lease term				10 years
Lessee, Operating Lease, Existence of Option to Extend [true false]				false
Minimum | First Lease Amendment
Lessee Lease Description [Line Items]
Increase in annual fixed rental payments		$ 0.8
Minimum | Second Lease Amendment
Lessee Lease Description [Line Items]
Increase in annual fixed rental payments	$ 1.1
Maximum | First Lease Amendment
Lessee Lease Description [Line Items]
Increase in annual fixed rental payments		$ 1.1
Maximum | Second Lease Amendment
Lessee Lease Description [Line Items]
Increase in annual fixed rental payments	$ 3

Leases - Summary of Lease Expen

Leases - Summary of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease cost	$ 7,802	$ 6,435
Variable lease cost	2,618	1,798
Total lease cost	$ 10,420	$ 8,233

Leases - Summary of Amounts Rep

Leases - Summary of Amounts Reported in Consolidated Balance Sheets and Weight-average Lease Term and Discount rate Information (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets
Operating lease right-of-use assets	$ 40,048	$ 44,444
Liabilities
Operating lease liabilities, current	3,830	3,272
Operating lease liabilities, non-current	31,830	35,640
Total lease liabilities	$ 35,660	$ 38,912
Weighted Average Lease Term and Discount Rate
Weighted-average remaining lease term (years)	6 years 8 months 12 days	7 years 8 months 12 days
Weighted-average discount rate	8.20%	8.20%

Leases - Summary of Other Lease

Leases - Summary of Other Lease Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities [Abstract]
Operating cash flows for operating leases	$ 6,658	$ 13,311
Right-of-use assets obtained in exchange for lease obligations		$ 23,376

Leases - Summary of Future Leas

Leases - Summary of Future Lease Payments for Noncancelable Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 6,591
2025	6,651
2026	6,681
2027	6,882
2028	7,088
Thereafter	12,902
Total lease payments	46,795
Less: imputed interest	(11,135)
Present value of lease liabilities	$ 35,660	$ 38,912

Defined Contribution Benefit _2

Defined Contribution Benefit Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Defined contribution benefit plan, matching percentage			100%
Defined contribution benefit plan, first percentage			1%
Defined contribution benefit plan, additional percentage			50%
Defined contribution benefit plan, minimum percentage of employee's compensation			1%
Defined contribution benefit plan, maximum percentage of employee's compensation			6%
Defined contribution benefit plan, matching contributions amount	$ 1	$ 0.8

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Federal Statutory Income Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal income tax rate	21%	21%
State income tax benefit	6.10%	5.80%
Permanent items	(0.90%)	(0.40%)
Research tax credits	5.70%	5.50%
Other	(0.40%)	(0.40%)
Valuation allowance	(31.50%)	(31.50%)

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Components of Deferred tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Accrued expenses	$ 1,428	$ 1,224
Federal net operating loss carryforwards	39,934	32,262
State net operating loss carryforwards	11,423	8,919
Tax credits	17,062	10,712
Stock compensation	1,545	1,248
R&D Capitalization	33,503	14,881
Amortization	1,464	429
Lease liability	9,746	10,445
Total deferred tax assets	116,105	80,120
Valuation allowance	(104,403)	(68,348)
Net total deferred tax assets	11,702	11,772
Deferred tax liabilities:
Lease right of use asset	(10,945)	(11,951)
Depreciation and amortization	(757)	179
Total deferred tax liabilities	(11,702)	(11,772)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Deferred tax assets valuation allowance	$ 104,403,000	$ 68,348,000
Change in deferred tax asset valuation allowance	$ 36,100,000	28,900,000
Considered period of ownership for annual limitation of net operating loss and tax credit carryforwards	3 years
Considered percentage of ownership for annual limitation of net operating loss and tax credit carryforwards	50%
Unrecognized tax benefits	$ 0	0
Accrued interest and penalties related to uncertain tax positions	$ 0	$ 0
Income tax examination, description	As of December 31, 2023, there were no income tax examinations in progress
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 190,200,000
Net operating loss carryforwards not subject to expiration	188,300,000
Net operating loss carryforwards subject to expiration	$ 1,900,000
Net operating loss carryforwards expiration year	2037
Research and development tax credit carryforwards	$ 12,200,000
Tax credit carryforwards expiration year	2042
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 180,800,000
Net operating loss carryforwards expiration year	2043
Research and development tax credit carryforwards	$ 6,100,000
Tax credit carryforwards expiration year	2038

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss attributable to common stockholders	$ (117,863)	$ (92,094)
Denominator, basic
Weighted-average number of common shares outstanding, basic	67,191,973	39,551,420
Net loss per share attributable to common stockholders, basic	$ (1.75)	$ (2.33)
Denominator, diluted
Weighted-average number of common shares outstanding, diluted	67,191,973	39,551,420
Net loss per share attributable to common stockholders, diluted	$ (1.75)	$ (2.33)

Net Loss Per Share - Potential

Net Loss Per Share - Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per share	8,290,077	6,388,065
Unvested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per share	10,299	83,459
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per share	1,113,381	1,430,200