Theseus Pharmaceuticals (THRX) 10-K 9 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 01, 2023	Jun. 30, 2022
Document and Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	001-40869
Entity Registrant Name	Theseus Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-0712806
Entity Address, Address Line One	314 Main Street
Entity Address, City or Town	Cambridge
Entity Address State Or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	857
Local Phone Number	400-9491
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	THRX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 85.6
Entity Common Stock, Shares Outstanding		43,561,124
Entity Central Index Key	0001745020
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Boston, Massachusetts

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 94,605	$ 244,662
Short-term marketable securities	103,374
Prepaid expenses and other current assets	4,137	3,309
Total current assets	202,116	247,971
Property and equipment, net	416	11
Operating lease right-of-use asset	4,334
Long-term marketable securities	13,817
Other assets	1,764	2,947
Total assets	222,447	250,929
Current liabilities:
Accounts payable	4,973	1,002
Accrued expenses and other current liabilities	5,414	2,678
Operating lease liability, current portion	743
Total current liabilities	11,130	3,680
Operating lease liability, net of current portion	3,236
Restricted stock liability, net of current portion	466	815
Total liabilities	14,832	4,495
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock, $0.0001 par value; 500,000,000 shares authorized as of December 31, 2022 and December 31, 2021; 38,734,446 and 38,702,650 shares issued and outstanding as of December 31, 2022 and December 31, 2021, respectively	4	4
Additional paid-in capital	320,183	308,008
Accumulated deficit	(112,186)	(61,578)
Accumulated other comprehensive loss	(386)
Total stockholders' equity	207,615	246,434
Total liabilities and stockholders' equity	$ 222,447	$ 250,929

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Consolidated Balance Sheets
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	38,734,446	38,702,650
Common stock, shares outstanding	38,734,446	38,702,650

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating expenses:
Research and development	$ 35,698	$ 18,328
General and administrative	18,388	9,008
Total operating expenses	54,086	27,336
Loss from operations	(54,086)	(27,336)
Other income (expense), net:
Other income, net	3,478	28
Total other income, net	3,478	28
Net loss attributable to common stockholders-basic	(50,608)	(27,308)
Net loss attributable to common stockholders- diluted	$ (50,608)	$ (27,308)
Weighted-average common stock outstanding-basic	38,490,104	9,631,818
Weighted-average common stock outstanding- diluted	38,490,104	9,631,818
Net loss per share attributable to common stockholders-basic	$ (1.31)	$ (2.84)
Net loss per share attributable to common stockholders- diluted	$ (1.31)	$ (2.84)
Net loss	$ (50,608)	$ (27,308)
Unrealized loss on marketable securities	(386)
Total comprehensive loss	$ (50,994)	$ (27,308)

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	SERIES A REDEEMABLE CONVERTIBLE PREFERRED STOCK	SERIES B REDEEMABLE CONVERTIBLE PREFERRED STOCK	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT	Total
Beginning balance at Dec. 31, 2020	$ 41,289
Beginning balance, shares at Dec. 31, 2020	16,734,179
Increase (Decrease) in Temporary Equity
Issuance of redeemable convertible preferred stock, net of issuance costs		$ 99,892
Issuance of redeemable convertible preferred stock, net of issuance costs, shares		8,741,726
Conversion of redeemable convertible preferred stock into common stock	$ (41,289)	$ (99,892)
Conversion of redeemable convertible preferred stock into common stock (in shares)	(16,734,179)	(8,741,726)
Beginning balance at Dec. 31, 2020						$ (34,270)	$ (34,270)
Beginning balance (in shares) at Dec. 31, 2020			882,789
Increase (Decrease) in Stockholders' Equity
Conversion of redeemable convertible preferred stock into common stock			$ 3	$ 141,178			141,181
Conversion of redeemable convertible preferred stock into common stock (in shares)			25,475,905
Vesting of restricted stock (in shares)			341,720
Issuance of common stock upon closing of initial public offering, net of issuance costs			$ 1	162,469			162,470
Issuance of common stock upon closing of initial public offering, net of issuance costs (in shares)			11,172,190
Stock-based compensation				4,361			4,361
Net loss						(27,308)	(27,308)
Ending balance at Dec. 31, 2021			$ 4	308,008		(61,578)	246,434
Ending balance (in shares) at Dec. 31, 2021			37,872,604
Increase (Decrease) in Stockholders' Equity
Vesting of restricted stock (in shares)			374,084
Stock-based compensation				11,412			11,412
Issuance of common stock under Employee Stock Purchase Plan				182			182
Issuance of common stock under Employee Stock Purchase Plan (in shares)			31,796
Vesting of early exercised options				581			581
Vesting of early exercised options (in shares)			144,137
Unrealized loss on marketable securities					$ (386)		(386)
Net loss						(50,608)	(50,608)
Ending balance at Dec. 31, 2022			$ 4	$ 320,183	$ (386)	$ (112,186)	$ 207,615
Ending balance (in shares) at Dec. 31, 2022			38,422,621

Consolidated Statements of Re_2

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Payment of issuance costs	$ 16,285
SERIES B REDEEMABLE CONVERTIBLE PREFERRED STOCK
Issuance costs	$ 208

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (50,608,000)	$ (27,308,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	50,000	2,000
Stock-based compensation expense	11,412,000	4,361,000
Amortization and accretion of marketable securities	(655,000)
Non-cash interest income	(83,000)
Non-cash operating lease expense	388,000
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(829,000)	(3,196,000)
Other assets	1,184,000	(2,525,000)
Accounts payable	3,971,000	(150,000)
Accrued expenses and other current liabilities	2,968,000	1,623,000
Operating lease liability	(743,000)
Net cash used in operating activities	(32,945,000)	(27,193,000)
Cash flows from investing activities:
Purchases of short-term and long-term marketable securities	(191,439,000)
Sales and maturities of short-term and long-term marketable securities	74,600,000
Purchases of property and equipment	(455,000)
Net cash used in investing activities	(117,294,000)
Cash flows from financing activities:
Proceeds from initial public offering, net of underwriting discounts and commissions of $12,513		166,242,000
Payment of initial public offering costs		(3,752,000)
Proceeds from issuance of Series B redeemable convertible preferred stock, net of issuance costs of $208		99,892,000
Proceeds from early exercise of options		1,395,000
Proceeds from issuance of common stock under employee stock purchase plan	182,000
Net cash provided by financing activities	182,000	263,777,000
Net (decrease) increase in cash and cash equivalents	(150,057,000)	236,584,000
Cash and cash equivalents at beginning of year	245,041,000	8,457,000
Cash and cash equivalents at end of period	94,984,000	245,041,000
Supplemental disclosure of cash flows:
Conversion of redeemable convertible preferred stock into common stock		141,181,000
Purchases of property and equipment in accounts payable		12,000
Deferred financing costs in accounts payable		$ 19,000
Vesting of early exercised options	581,000
Obtaining a right-of-use asset in exchange for an operating lease liability	$ 4,721,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2022
Cash, cash equivalents, and restricted cash balances:
Cash and cash equivalents	$ 244,662	$ 94,605
Restricted cash (included in other assets)	379	379
Total cash, cash equivalents, and restricted cash	245,041	$ 94,984
Net of underwriting discounts and commissions	12,513
SERIES B REDEEMABLE CONVERTIBLE PREFERRED STOCK
Cash, cash equivalents, and restricted cash balances:
Issuance costs	$ 208

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2022
Nature of the Business
Nature of the Business	1. Nature of the Business Theseus Pharmaceuticals, Inc. (“Theseus” or the “Company”) is a clinical biopharmaceutical company focused on improving the lives of cancer patients through the discovery, development and commercialization of transformative targeted therapies. The Company was incorporated in December 2017 under the laws of the State of Delaware, and its principal offices are in Cambridge, Massachusetts. Reverse Stock Split On September 27, 2021, the Company effected a one-for-1.32286 reverse stock split of shares of the Company’s common stock and convertible preferred stock. All of the share and per share amounts included in the accompanying consolidated financial statements and notes thereto have been retroactively adjusted for all periods presented to give effect to this reverse stock split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. Shares of common stock underlying outstanding stock options were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased in accordance with the terms of the appropriate securities agreements. Stockholders entitled to fractional shares as a result of the reverse stock split received a cash payment in lieu of receiving fractional shares. Initial Public Offering On October 12, 2021, the Company closed the initial public offering (“IPO”), in which it sold 10,000,200 shares of common stock at a public offering price of $16.00 per share. On October 25, 2021, the underwriters partially exercised their option to purchase an additional 1,171,990 shares of common stock at the public offering price of $16.00 per share. After deducting underwriting discounts, commissions and offering expenses, the aggregate net offering proceeds raised in the IPO were approximately $162.5 million. Upon the closing of the IPO, all of the Company’s outstanding shares of redeemable convertible preferred stock automatically converted into an aggregate of 25,475,905 shares of common stock. ​ In connection with the closing of the IPO, the Company amended and restated its certificate of incorporation to among other things: (a) authorize 500,000,000 shares of voting common stock; (b) eliminate all references to the previously existing series of redeemable convertible preferred stock; and (c) authorize 50,000,000 shares of preferred stock that may be issued from time to time by the Company’s board of directors (the “Board”) in one or more series. Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative US GAAP as found in the ASC and as amended by Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Liquidity The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. The Company’s development programs will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Because of the numerous risks and uncertainties associated with product development, the Company is unable to predict the timing or amount of increased expenses or when or if the Company will be able to achieve or maintain profitability. Even if the Company is able to generate revenue from product sales, the Company may not become profitable. If the Company fails to become profitable or is unable to sustain profitability on a continuing basis, then the Company may be unable to continue its operations at planned levels and be forced to reduce or terminate its operations. The Company expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of Theseus Pharmaceuticals, Inc. and Theseus Securities Corporation, which is a Massachusetts subsidiary. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The preparation of consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Estimates and judgments are based on historical information and other market-specific or various relevant assumptions, including in certain circumstances, future projections, that management believes to be reasonable under the circumstances. Actual results could differ materially from estimates. Significant estimates and assumptions are used for, but not limited to, the accruals for research and development expenses, the incremental borrowing rate for determining the operating lease right-of-use (“ROU”) asset and lease liabilities, and for periods prior to the completion of the IPO, the determination of fair value of equity instruments, and the fair value of the preferred stock tranche rights and the anti-dilution right, and stock-based compensation expense. Concentration of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and marketable securities. Periodically, 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 have 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. Such deposits have and will continue to exceed federally insured limits. The Company has not experienced any losses on its cash deposits. The Company’s short-term and long-term marketable securities are invested in high grade securities with limited concentration in any one issuer, and as a result, the Company believes represent minimal credit risk. Fair Value of Financial Instruments The Company categorizes its assets and liabilities measured at fair value in accordance with ASC Topic 820, Fair Value Measurement ● Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities; ● Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; or ● Level 3—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Cash and Cash Equivalents Cash includes cash in readily available checking accounts. Cash is carried at cost, which approximates its fair value. The Company considers all highly liquid marketable securities with original maturities of three months or less at the date of purchase to be cash equivalents. Cash equivalents are carried at fair market value based on quoted prices for identical assets. Restricted Cash Restricted cash consists of a restricted cash deposit of $0.4 million which serves as collateral for a letter of credit issued to the landlord of the Company’s leased facility for a security deposit upon entering into the lease in September 2021. The Company classified this amount as restricted cash in the accompanying consolidated balance sheet within other assets as of December 31, 2022 and 2021. Marketable Securities All marketable securities have been classified as “available-for-sale” and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Marketable securities with contractual maturities less than 12 months at the balance sheet date are considered short-term marketable securities. Those marketable securities with contractual maturities 12 months or greater at the balance sheet date are considered long-term marketable securities. Dividend and interest income are recognized in the Company’s consolidated statements of operations and comprehensive loss when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). The cost of the Company’s available-for-sale debt securities is adjusted for amortization of premium and accretion of discounts to maturity. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in statements of operations, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss). Property and Equipment, net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets as follows: ​ ​ ​ ​ Estimated Useful Life (Years) Office equipment ​ 5 years Computer equipment and software ​ 3 years Furniture and fixtures ​ 7 years Leasehold improvements ​ Lesser of asset useful life or lease term ​ Costs for capital assets not yet placed into service are capitalized as construction-in-progress and are depreciated once placed into service. When an item is sold or retired, the costs and related accumulated depreciation are eliminated, and the resulting gain or loss, if any, is included in the consolidated statement of operations. Repairs and maintenance costs are expensed as incurred. Leases Effective on January 1, 2021, the Company accounts for leases in accordance with ASC Topic 842, Leases A lease qualifies as a finance lease if any of the following criteria are met at the inception of the lease: (i) there is a transfer of ownership of the leased asset to the Company by the end of the lease term, (ii) the Company holds an option to purchase the leased asset that it is reasonably certain to exercise, (iii) the lease term is for a major part of the remaining economic life of the leased asset, (iv) the present value of the sum of lease payments equals or exceeds substantially all of the fair value of the leased asset, or (v) the nature of the leased asset is specialized to the point that it is expected to provide the lessor no alternative use at the end of the lease term. All other leases are recorded as operating leases. The Company enters into contracts that contain both lease and non-lease components. Non-lease components may include maintenance, utilities, and other operating costs. For all real estate asset classes, the Company combines the lease and non-lease components of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement of ROU assets and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs. Finance and operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. If the rate implicit is not readily determinable, the Company utilizes an estimate of its incremental borrowing rate based upon the available information at the lease commencement date. ROU assets are further adjusted for initial direct costs, prepaid rent, or incentives received. Operating lease payments are expensed using the straight-line method as an operating expense over the lease term. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Finance lease assets are amortized to depreciation expense using the straight-line method over the shorter of the useful life of the related asset or the lease term. Finance lease payments are bifurcated into (i) a portion that is recorded as interest expense and (ii) a portion that reduces the finance liability associated with the lease. Impairment of Long-lived Assets Long-lived assets consist of property and equipment. The Company reviews the recoverability of its long-lived assets, including the related useful lives, whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset might not be recoverable, based on undiscounted cash flows. If such assets are considered to be impaired, an impairment loss is recognized and is measured as the amount by which the carrying amount of the assets exceed their estimated fair value, which is measured based on the projected discounted future net cash flows arising from the assets. There were no impairments for the years ended December 31, 2022 and 2021. Accrued Research and Development Costs The Company records accrued liabilities for estimated costs of research and development activities conducted by service providers for sponsored research, preclinical studies and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued expenses in the accompanying consolidated balance sheets and within research and development expense in the accompanying statements of operations. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with service providers. The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities. The Company has not experienced any material differences between accrued costs and actual costs incurred since its inception. Deferred Issuance Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred issuance costs until such financings are consummated. After consummation of such an equity financing, these costs are recorded as a reduction of the proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred issuance costs, currently recorded within other assets, will be expensed immediately as a charge to operating expenses in the statements of operations and comprehensive loss. On October 6, 2021, the Company completed its IPO. Accordingly, the Company recognized deferred issuance costs of $3.8 million as a reduction from the gross proceeds associated with the closing of the IPO through additional paid-in capital in the accompanying consolidated balance sheet as of December 31, 2021. Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research and development activities on the Company’s behalf. Patent Costs The Company expenses all costs as incurred in connection with patent applications, including direct application fees, and the legal and consulting expenses related to making such applications, and such costs are included in general and administrative expenses within the Company’s statements of operations. Stock-based Compensation The Company’s stock-based compensation plan grants awards to employees and non-employees that may include stock options, restricted stock awards, restricted stock units, and other stock-based awards, and recognizes the expense in the consolidated statement of operations and comprehensive loss based on their grant date fair values. The fair values of stock options are estimated on the date of grant using the Black-Scholes option-pricing model. The fair values of restricted stock awards and restricted stock units are based on the fair value of the Company’s common stock on the date of grant. The estimated grant date fair value of stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the award. The Company has performance-based vesting conditions in some of its awards, and all performance-based milestones have been met or waived as of December 31, 2021. The Company accounts for awards granted to non-employees using the same treatment as awards granted to employees. The Company recognizes forfeitures as they occur. Estimating the fair value of stock options using the Black-Scholes option-pricing model requires the input of subjective assumptions including: the fair value of common stock, the expected term of stock options, the expected volatility of common stock, the risk-free interest rate for a period that approximates the expected term of stock options, and expected dividend yield. The fair value is the closing price of the Company’s common stock on the Nasdaq Global Select Market as reported on the date of grant. The expected term is estimated using the “simplified” method for awards that qualify as “plain-vanilla”, which deems the expected term to be the midpoint between the vesting date and the contractual life of the stock-based awards. For expected volatility, the Company based its computation on the historical volatility of a representative group of public companies with similar characteristics, including stage of product development, life science industry focus, length of trading history and similar vesting provisions. The risk-free interest rate is based on the US Treasury yield in effect at the time of grant for zero-coupon US Treasury notes with maturities approximately equal to the expected term of the awards. The expected dividend yield is assumed to be zero as the Company has never paid cash dividends on its common stock and has no plans to pay cash dividends on common stock in the visible future. Certain assumptions used in the Black-Scholes option-pricing model represent management’s best estimates and involve a number of variables, uncertainties and assumptions and the application of management’s judgment, as they are inherently subjective. If any assumptions change, the Company’s stock-based compensation expense could be materially different in the future. The Company’s equity incentive plan allows for but does not require the inclusion of early exercise provisions in individual awards. The unvested shares of any restricted stock awards are held in escrow as the stock award vests or until award holder termination, whichever occurs first. In the event of a termination, the Company has the right of repurchase, at its option, the portion of unvested stock awards from the terminated award holder at their original issuance price. For all unvested stock option awards for which the award recipient has transferred cash to the Company prior to the vesting date, a liability is established related to the cash received for the unvested portion of the stock awards, which represents the Company’s obligation if all award holders were to be terminated. Prior to the Company’s IPO, the estimated fair value of its common stock was determined by the Board of Directors as of the date of each option grant, with input from management, considering the most recently available third-party valuations of common stock and the Board’s assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent valuation through the date of the grant. Historically, these independent third-party valuations of the Company’s equity instruments were performed contemporaneously with identified value inflection points. 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 available methods for allocating the enterprise value across classes of series of capital stock in determining the fair value of the Company’s common stock at each valuation date. The Company issues rights to employees to purchase common stock under the Theseus Pharmaceuticals, Inc. 2021 Employee Stock Purchase Plan (the “ESPP”). The purchase price of common stock under the Company’s ESPP is equal to 85% of the lesser of (i) the fair market value per share of common stock on the first trading day of an offering period and (ii) the fair market value per share of common stock on the purchase date. The fair value of the discounted purchases made under the ESPP is calculated using the Black-Scholes option-pricing model. The fair value of the look-back provision plus the 15% discount is recognized as compensation expense over the 180-day Net Loss Per Share The Company follows the two-class method when computing net loss allocable to common securities per share as the Company has issued shares that meet the definition of participating securities, see Note 13 for additional information. During periods of loss, there is no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company. Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding during the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, diluted net loss per share attributable to common stockholders is calculated by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding after giving consideration to the dilutive effect of convertible preferred stock, restricted common stock, restricted stock units and stock options that are outstanding during the period. The Company has generated a net loss in all periods presented, therefore the basic and diluted net loss per share attributable to common stockholders are the same as the inclusion of the potentially dilutive securities would be anti-dilutive. Redeemable Convertible Preferred Stock Prior to the Company’s IPO, the Company’s redeemable convertible preferred stock was classified as temporary equity in the consolidated balance sheets and excluded from stockholders’ equity (deficit) as the potential redemption of such stock was outside the Company’s control. Upon the completion of the Company’s IPO on October 6, 2021, all outstanding shares of the Company’s redeemable convertible preferred stock converted into shares of the Company’s common stock. Income Taxes Income taxes for the Company are recorded in accordance with ASC Topic 740, Income Taxes The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions. The tax benefits recorded are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is “more likely than not” to be realized following resolution of any uncertainty related to the tax benefit, assuming that the matter in question will be raised by the tax authorities. The Company’s policy is to recognize interest and penalties accrued on any uncertain tax positions, if any, as a component of income tax expense in its statements of operations and comprehensive loss. Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders, including unrealized gains and losses on marketable securities. For the year ended December 31, 2022, the unrealized losses on marketable securities represent the only component of other comprehensive loss that is excluded from the reported net loss. For the year ended December 31, 2021, there were no differences between net loss and comprehensive loss. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company has determined it operates in a single operating segment and has one reportable segment. All long-lived assets of the Company reside in the US. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	12 Months Ended
	Dec. 31, 2022
Fair Value of Financial Assets and Liabilities
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities The carrying values of other current assets, accounts payable, and accrued expenses approximate their fair values due to the short-term nature of these instruments. The Company’s marketable securities, which may include both short-term and long-term marketable securities consisting of high-quality, marketable debt instruments of corporations, are measured at fair value in accordance with the fair value hierarchy. Assets measured at fair value on a recurring basis as of December 31, 2022 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2022 ​ LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds $ 6,846 ​ $ — ​ $ — ​ $ 6,846 Commercial paper ​ ​ — ​ ​ 3,989 ​ ​ — ​ ​ 3,989 Marketable Securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper ​ ​ — ​ ​ 25,187 ​ ​ — ​ ​ 25,187 Corporate debt securities ​ ​ — ​ ​ 45,673 ​ ​ — ​ ​ 45,673 Asset-backed securities ​ ​ — ​ ​ 13,574 ​ ​ — ​ ​ 13,574 Government securities ​ ​ — ​ ​ 32,757 ​ ​ — ​ ​ 32,757 Total financial assets ​ $ 6,846 ​ $ 121,180 ​ $ — ​ $ 128,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of the year ended December 31, 2021, there were no assets or liabilities measured at fair value. During the year ended December 31, 2022, there were no transfers between fair value levels.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2022
Marketable Securities
Marketable Securities	4. Marketable Securities The Company’s investment policy defines allowable investments and establishes guidelines relating to credit quality, diversification, and maturities of its to preserve principal and maintain liquidity. In accordance with the Company’s investment policy, it has invested funds in marketable securities as of December 31, 2022. The Company’s are classified as available-for-sale investments. The cost, gross unrealized holding gains, gross unrealized holding losses and fair value of by types and classes of security at December 31, 2022 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, 2022 ​ ​ MATURITY ​ AMORTIZED ​ UNREALIZED ​ UNREALIZED ​ FAIR ​ IN YEARS COST GAIN LOSS VALUE Commercial paper ​ less than 1 ​ $ 25,187 ​ $ — ​ $ — ​ $ 25,187 Corporate debt securities ​ less than 1 ​ ​ 39,071 ​ ​ 9 ​ ​ (185) ​ ​ 38,895 Asset-backed securities ​ less than 1 ​ ​ 8,555 ​ ​ 2 ​ ​ (10) ​ ​ 8,547 Government securities ​ less than 1 ​ ​ 30,892 ​ ​ 8 ​ ​ (155) ​ ​ 30,745 Short-term marketable securities ​ ​ ​ $ 103,705 ​ $ 19 ​ $ (350) ​ $ 103,374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt securities ​ 1 - 2 ​ ​ 6,783 ​ ​ — ​ ​ (5) ​ ​ 6,778 Asset backed securities ​ 1 - 2 ​ ​ 5,074 ​ ​ — ​ ​ (47) ​ ​ 5,027 Government securities ​ 1 - 2 ​ ​ 2,015 ​ ​ — ​ ​ (3) ​ ​ 2,012 Long-term marketable securities ​ ​ ​ $ 13,872 ​ $ — ​ $ (55) ​ $ 13,817 ​ The Company reviews its to identify and evaluate investments that have an indication of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. At December 31, 2022, the Company did not have any securities in material unrealized loss positions. The Company generally does not intend to sell any prior to recovery of their amortized cost basis for any in an unrealized loss position. Further, such are invested in high grade securities. As such, the Company has classified these losses as temporary in nature. The Company has determined that there were no material declines in fair value of its due to credit-related factors as of December 31, 2022.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2022
Property and Equipment
Property and Equipment	5. Property and Equipment ​ Property and equipment, net consisted of the following as of December 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ ​ 2022 2021 Computer equipment ​ $ 50 ​ $ 12 Furniture and fixtures ​ ​ 341 ​ ​ — Office equipment ​ ​ 76 ​ ​ — Property and equipment ​ ​ 467 ​ ​ 12 Less: accumulated depreciation ​ (51) ​ (1) Property and equipment, net ​ $ 416 ​ $ 11 ​ ​ ​ ​ ​ ​ ​ ​ Depreciation expense for each of the years ended December 31, 2022 and 2021 was approximately $50,000 and $2,000, respectively. There were no impairments recorded to date.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2022
Accrued Expenses
Accrued Expenses	6. Accrued Expenses ​ Accrued expenses consisted of the following as of December 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Accrued research and development ​ $ 1,498 ​ $ 233 Accrued legal ​ ​ 164 ​ ​ 199 Accrued compensation and benefits ​ ​ 3,130 ​ ​ 1,353 Accrued other ​ ​ 273 ​ ​ 313 Restricted stock liability, current ​ ​ 349 ​ ​ 580 Total accrued expenses and other current liabilities ​ $ 5,414 ​ $ 2,678 ​ ​ ​ ​ ​ ​ ​ ​

License Agreement

License Agreement	12 Months Ended
	Dec. 31, 2022
License Agreement
License Agreement	7. License Agreement Agreement Description In June 2018, the Company entered into a license agreement with ARIAD (the “ARIAD License Agreement”), for an exclusive, transferable (subject to certain restrictions), sublicensable (subject to certain conditions), worldwide license, under certain of ARIAD’s patent rights, know-how and compounds and a certain ARIAD chemical library, to develop, use, manufacture, market and commercialize certain compounds, and products that contain such compounds, that are therapeutically useful for the treatment of diseases and disorders in humans, including with respect to KIT (referred to as C-KIT, CD117 and stem cell factor receptor in the ARIAD License Agreement). The Company is required to pay ARIAD tiered royalty payments that are low- to mid-single digits of the Company’s future net sales and those of its sublicensees of each product comprising a licensed ARIAD compound in each country. The Company is also responsible for costs relating to the prosecution and maintenance of the licensed patents. The agreement contains anti-stacking and generic competition provisions on the royalties whereby the Company may deduct a percentage of the amounts due for royalties from its payments if the Company enters into a third-party license agreement, and may reduce the rates in the event a generic product is being marketed and sold by a third party and the average net sales as measured over a specified period of time are at least a certain percentage lower than the average net sales during a specified period of time immediately prior to the launch of the generic product. The term of the agreement commenced in June 2018 and unless earlier terminated as provided in the agreement for breach of terms by either party or for convenience by the Company with advanced written notice, shall continue in full force and effect, on a country-by-country and product-by-product basis until the date on which the royalty term in such country with respect to such product expires. The royalty term is the period from the first commercial sale of such product in such country until the later of (a) the expiry of all patents that cover the product in such country or (b) ten years after the first commercial sale. The ARIAD License Agreement terminates, on a product-by-product and country-by-country basis, on expiration of the royalty term for such product for the applicable country. Thereafter, the licenses from ARIAD to the Company with respect to such product for such country will convert to a fully paid, royalty-free, irrevocable and perpetual license.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases
Leases	8. Leases On July 19, 2021, the Company entered into a lease agreement for office space in Cambridge, Massachusetts, on a month-to-month basis, which was determined to be a short-term lease as the Company was not reasonably certain to extend the lease beyond twelve months. The Company recognized lease payments as incurred over the lease term, and recognized short-term lease expense of $0.2 million for each of the years ended December 31, 2022 and 2021. ​ On September 16, 2021, the Company entered into an operating lease agreement for 7,351 rentable square feet of office space in Cambridge, Massachusetts. The premises required additional build-out at the time the lease agreement was entered into. The lease commenced in March 2022 when the space was made available for use. Upon lease commencement, the Company recorded a ROU asset of $4.7 million and a corresponding lease liability of $4.7 million. The lease has a term of 7 years and an expiration date of March 22, 2029, with lease payments made on a monthly basis. The initial annual base rent is approximately $0.8 million, subject to a 3% annual rent increase, plus an allocation of the Company’s proportionate share of building operating costs such as maintenance, utilities, and insurance that are treated as variable costs and excluded from the measurement of the lease. The Company is entitled to one option to extend the lease term for an additional period of five years. The option to extend the lease term is not reflected in the ROU asset and lease liability as it is not reasonably certain of being exercised. Pursuant to the terms of the lease, the Company provided a security deposit in the form of a letter of credit in the amount of approximately $0.4 million upon signing, which is recognized as restricted cash within other assets on the consolidated balance sheets. As of December 31, 2022, the weighted-average remaining lease term was 6.3 years, and the weighted-average discount rate was 9.1%. The following table presents future lease payments under the terms of the Company’s operating leases as of December 31, 2022, including a reconciliation to the present value of operating lease liabilities recognized in the consolidated balance sheet (in thousands): ​ ​ ​ ​ ​ ​ Fiscal Year ​ Operating Lease 2023 ​ ​ $ 774 2024 ​ ​ ​ 797 2025 ​ ​ ​ 821 2026 ​ ​ ​ 846 Thereafter ​ ​ ​ 1,996 Total future minimum lease payments ​ ​ ​ 5,234 Less: imputed interest ​ ​ ​ (1,255) Present value of lease liabilities ​ ​ $ 3,979 ​

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies.
Commitments and Contingencies	9. Commitments and Contingencies Legal Proceedings The Company may, from time to time, be party to litigation arising in the ordinary course of business. The Company was not subject to any material legal proceedings during the years ended December 31, 2022 and 2021, and no material legal proceedings are currently pending or, to the best of the Company’s knowledge, threatened. Indemnification Agreements The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to the indemnification agreements, the Company agrees to indemnify, hold harmless, and to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally the Company’s business partners, in connection with any US patent or any copyright or other intellectual property infringement claim by any third-party with respect to the Company’s products. The term of these indemnification agreements is generally perpetual any time after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. 401(k) Plan The Company maintains a defined-contribution plan under Section 401(k) of the Internal Revenue Code of 1986 (the “401(k) Plan”). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants to defer a portion of their annual compensation. Matching contributions to the 401(k) Plan may be made at the discretion of management. The Company contributed $0.4 million to the 401(k) Plan during the year ended December 31, 2022. There were no employer contributions made to the 401(k) Plan during the year ended December 31, 2021.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity
Stockholders' Equity	10. Stockholders’ Equity Preferred Stock The Company was authorized to issue up to 50,000,000 shares of preferred stock , $0.0001 par value per share, as of December 31, 2022 and 2021. There were no shares of preferred stock outstanding as of December 31, 2022 and 2021. Common Stock The Company was authorized to issue up to 500,000,000 shares of common stock, $0.0001 par value per share, as of December 31, 2022 and 2021. The voting, dividend and liquidation rights of the holders of the Company’s common stock are subject to and qualified by the rights, powers and preference of the holders of any series of preferred stock. Voting Rights Each share of common stock entitles the holder to one vote on all matters submitted to the stockholders for a vote. Dividends Subject to preferences that may apply to shares of preferred stock outstanding at the time, the holders of outstanding shares of the Company’s common stock are entitled to receive dividends out of funds legally available if and when the Board, in its discretion, determines to issue dividends. As of December 31, 2022, no cash dividends have been declared or paid. Liquidation Rights Upon the Company’s dissolution, liquidation, or winding-up, the assets legally available for distribution to stockholders are distributable ratably among holders of the Company’s common stock, subject to prior satisfaction of all outstanding debt and liabilities, and the preferential rights and payment of liquidation preferences, if any, on any outstanding shares of preferred stock.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2022
Stock-Based Compensation
Stock-Based Compensation	11. Stock-Based Compensation Equity Incentive Plans In September 2021, the Company adopted the Theseus Pharmaceuticals, Inc. 2021 Equity Incentive Plan (the “2021 Plan”), which replaced the 2018 Stock Incentive Plan (the “2018 Plan”) and allows for the issuance of stock options, restricted stock awards, restricted stock units (“RSUs”), and other types of equity awards. No further awards were made under the 2018 Plan as of the effective date of the 2021 Plan. Any options or awards outstanding under the 2018 Plan are governed by their existing terms. On the first day of each fiscal year of the Company during the term of the Plan, commencing on January 1, 2023 and ending on (and including) January 1, 2031, the aggregate number of Common Shares that may be issued under the Plan shall automatically increase by a number equal to the lesser of (a) five percent (5%) of the total number of Common Shares actually issued and outstanding on the last day of the preceding fiscal year, or (b) a number of Common Shares determined by the Board. As of December 31, 2022 and 2021, the number of shares reserved for issuance upon the exercise of outstanding options was 9,132,930 and 9,094,083, respectively. Of those shares reserved for issuance, there were 1,843,494 and 3,930,440 shares available for future grant as of December 31, 2022 and 2021, respectively. The 2021 Plan is administered by the Board (or its compensation committee), and the exercise prices, vesting and other restrictions for the awards are determined at the discretion of the Board, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the common stock on the date of grant. Stock options awarded under the 2021 Plan expire ten years after the grant date unless the Board sets a shorter term. Stock options granted to employees and nonemployees typically vest over four years. Shares of restricted stock awards granted to employees, officers, members of the Board, advisors, and consultants of the Company typically vest over five years. Certain executives who are option holders are able to early exercise stock option awards prior to full satisfaction of the vesting conditions. If and when this occurs, the executive receives restricted common stock upon exercise of the option, and the shares remain subject to the Company’s right of repurchase until the remaining vesting terms are met. During the year ended December 31, 2021, options to purchase 345,930 shares of common stock were exercised early. As of December 31, 2022 and December 31, 2021, the Company recognized $0.8 million and $1.4 million, respectively, as a liability related to the early exercise. The amount of remaining unvested shares related to the early exercise as of December 31, 2022 and December 31, 2021 were 201,793 and 345,930, respectively. There were no additional early exercises of options during the year ended December 31, 2022. Employee Stock Purchase Plan In September 2021, the Company’s board of directors adopted, and its stockholders approved, the ESPP, which became effective on October 6, 2021. The number of shares of common stock initially reserved for issuance under the ESPP is 400,000. In addition, on the first day of each fiscal year of the Company during the term of the ESPP, commencing on January 1, 2023 and concluding on January 1, 2041, the aggregate number of shares of common stock reserved for issuance under the ESPP shall automatically increase by a number equal to the lesser of (i) one percent (1%) of the total number of shares of common stock actually issued and outstanding on the last day of the preceding fiscal year, and (ii) a number of shares of common stock determined by the Company’s board of directors. Shares of common stock issued pursuant to the ESPP may be authorized but unissued shares or treasury shares. As of December 31, 2022, the number of shares of common stock that may be issued under the ESPP is 368,204. The ESPP enables eligible employees to purchase shares of common stock of the Company at the end of each offering period at a price equal to 85% of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant date of purchase. Participation in the ESPP is voluntary. Eligible employees become participants in the ESPP by enrolling in the plan and authorizing payroll deductions. During the year ended December 31, 2022, 31,796 shares of common stock were issued under the ESPP, at an average price of $5.86 per share. Cash received from purchases under the ESPP for the year ended December 31, 2022 was $0.2 million. The Company recorded stock-based compensation expense related to the ESPP of $0.2 million for the year ended December 31, 2022. Stock Option Valuation The assumptions that the Company used in Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted for the years ended December 31, 2022 and 2021 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Risk-free interest rate ​ 1.60% - 4.20% ​ 1.07% Expected term (in years) ​ 1.03 - 6.08 ​ 5.2 - 6.1 Expected volatility ​ 78.00% - 90.51% ​ 75.58% - 83.56% Expected dividend yield ​ 0.00% ​ 0.00% ​ ​ ​ ​ ​ ​ A summary of option activity under the Plans during the years ended December 31, 2022 and 2021 is as follows (in thousands except share, per share data and contractual terms): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE WEIGHTED-AVERAGE ​ ​ ​ ​ ​ PER-SHARE ​ REMAINING ​ AGGREGATE ​ ​ SHARES ​ EXERCISE PRICE ​ CONTRACTUAL TERM ​ INTRINSIC VALUE Outstanding as of December 31, 2021 ​ 5,163,643 ​ $ 4.31 9.29 ​ $ 44,463 Granted ​ 2,366,200 ​ 10.05 ​ Forfeited ​ (272,057) ​ (8.29) ​ ​ Outstanding as of December 31, 2022 ​ 7,257,786 ​ $ 5.95 8.58 ​ 10,750.63 Options vested and exercisable as of December 31, 2022 ​ 2,367,914 ​ $ 3.59 8.25 ​ $ 5,736.58 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The aggregate intrinsic value of stock 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 Company’s common stock. The weighted-average grant date fair value of options granted during the year ended December 31, 2022 was $6.93. Stock-based compensation expense for options granted of $10.8 million was recorded as of December 31, 2022. As of December 31, 2022, there was $23.8 million of unrecognized stock-based compensation expense related to unvested stock options. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 2.5 years as of December 31, 2022. The total fair value of options vested as of December 31, 2022 and 2021 was $10.5 million and $2.4 million, respectively. Restricted Stock Units The Company issues RSUs that generally vest over a four-year period with 25% of the RSUs vesting one year from the vesting commencement date, and the remainder vesting quarterly thereafter over the following 36 months. Any unvested shares underlying an RSU will be forfeited upon termination of services. The fair value of an RSU is equal to the fair market value price of the Company’s common stock on the date of grant. A summary of RSU activity during the year ended December 31, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE ​ ​ ​ ​ PER-SHARE GRANT-DATE ​ SHARES FAIR VALUE Unvested shares at December 31, 2021 — ​ $ — Granted 35,900 ​ 11.21 Forfeited ​ (4,250) ​ ​ 11.21 Unvested shares at December 31, 2022 31,650 ​ $ 11.21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022, there was $0.2 million of unrecognized stock-based compensation expense related to unvested RSUs. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 3.2 years as of December 31, 2022. There were no RSUs granted during the year ended December 31, 2021. Shares of Restricted Common Stock The Company issued shares of restricted common stock to its founders in May 2018, which vest monthly over five years through 2023. At issuance, these shares also contained certain performance-based vesting criteria which were associated with the milestone events applicable to the formerly outstanding shares of Series A preferred stock, two of which were achieved in 2020. In conjunction with the termination of the Series A preferred stock purchase agreement, the final performance-based vesting criteria was waived, leaving only service-based vesting criteria remaining for the founders’ shares through the end of the requisite service period. As noted above, certain executives who are option holders are able to early exercise stock option awards prior to full satisfaction of the vesting conditions. If and when such exercise occurs, the executive receives shares of restricted common stock. Early exercise shares are included in the table below. A summary of restricted stock activity under the Plan during the years ended December 31, 2022 and 2021 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE ​ ​ ​ ​ PER-SHARE GRANT-DATE ​ ​ SHARES ​ FAIR VALUE Unvested shares at December 31, 2021 830,046 ​ $ 2.85 Vesting of restricted common stock (518,221) ​ 2.18 Unvested shares at December 31, 2022 311,825 ​ $ 3.96 ​ ​ ​ ​ ​ ​ ​ As of December 31, 2022, there was $1.2 million of unrecognized stock-based compensation expense related to unvested restricted stock. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 1.7 years as of December 31, 2022. Stock-based Compensation Expense Total stock-based compensation expense recorded as research and development and general and administrative expenses, respectively, for employees, directors and non-employees during the years ended December 31, 2022 and 2021 was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Research and development ​ $ 6,612 ​ $ 2,250 General and administrative ​ ​ 4,800 ​ ​ 2,111 ​ ​ $ 11,412 ​ $ 4,361 ​ ​ ​ ​ ​ ​ ​ ​ During the year ended December 31, 2022, the Company modified the terms of certain equity awards held by a departing employee, resulting in $1.8 million of stock-based compensation expense.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Taxes
Income Taxes	12. Income Taxes The Company has not recorded a current or deferred tax provision for the years ended December 31, 2022 and 2021. The effective income tax rate differed from the amount computed by applying the federal statutory rate to the Company’s loss before income taxes as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Tax effected at statutory rate ​ 21.0 % ​ 21.0 % State taxes ​ ​ 5.6 ​ ​ 5.3 ​ Stock compensation ​ ​ (1.7) ​ ​ (3.0) ​ Non-deductible expenses ​ ​ (0.9) ​ ​ — ​ Research and development credits ​ ​ 3.6 ​ ​ 3.3 ​ ​ ​ ​ 27.6 ​ ​ 26.6 ​ Change in valuation allowance ​ ​ (27.6) ​ ​ (26.6) ​ Total ​ ​ — % ​ — % ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred tax assets and liabilities consist of the following at December 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Deferred Tax Assets ​ ​ ​ ​ ​ ​ Net operating loss carryforwards $ 12,957 $ 9,420 Research and development credits ​ ​ 2,670 ​ ​ 916 Stock-based compensation expense ​ ​ 1,506 ​ ​ 116 Accruals and reserves ​ ​ 717 ​ ​ 367 Intangible assets ​ ​ 647 ​ ​ 702 Operating lease liability ​ ​ 1,087 ​ ​ — Capitalized research and development ​ ​ 7,238 ​ ​ — Gross deferred tax assets ​ ​ 26,822 ​ ​ 11,521 Deferred Tax Liabilities ​ ​ ​ ​ ​ ​ Depreciation ​ $ (114) ​ $ (3) Operating lease right-of-use asset ​ ​ (1,184) ​ ​ — Gross deferred tax liabilities ​ ​ (1,298) ​ ​ (3) Net deferred tax assets before valuation allowance ​ ​ 25,524 ​ ​ 11,518 Valuation allowance ​ ​ (25,524) ​ ​ (11,518) Net deferred tax asset ​ $ — $ — ​ ​ ​ ​ ​ ​ ​ ​ As required by ASC 740, the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which is composed principally of net operating loss carryforwards. The Company has determined that it is more likely than not that the Company will not realize the benefits of its federal and state deferred tax assets, and, as a result, a valuation allowance of $25.5 million and $11.5 million has been established at 2022 and 2021, respectively. The change in the valuation allowance was $14.0 million and $7.3 million for the years ended December 31, 2022 and 2021. Beginning in 2022, Tax Cuts and Jobs Act (“TCJA”) amended Section 174 and now requires US-based and non-U.S-based research and experimental (“R&E”) expenditures to be capitalized and amortized over a period of five The Company has incurred NOLs from inception. At December 31, 2022, the Company had federal and state NOL carryforwards of approximately $47.0 million and $48.9 million, respectively, available to reduce future taxable income. The federal NOLs are not subject to expiration and the state NOLs begin to expire in 2037. As of December 31, 2022, the Company also had federal and state research and development tax credit carryforwards of approximately $1.8 million and $1.0 million, respectively, to offset future income taxes, which will begin to expire beginning in December 2035. Under the provisions of the Internal Revenue Code, 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 percentage points, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future 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 completed numerous financings since its inception, which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future. In addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed. The Company follows the provisions of ASC 740-10, “ Accounting for Uncertainty in Income Taxes For the years ended December 31, 2022 and 2021, no estimated interest or penalties were recognized on uncertain tax positions. The Company does not expect any significant change in its uncertain tax positions in the next 12 months. The Company files US federal and state income tax returns and is generally subject to income tax examinations by these authorities for all tax years after December 31, 2017. Currently, no federal or state income tax returns are under examination by the respective income tax authorities.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2022
Net Loss Per Share
Net Loss Per Share	13. Net Loss Per Share Basic and diluted loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Numerator: ​ ​ ​ ​ ​ ​ Net loss ​ $ (50,608) ​ $ (27,308) Net loss attributable to common stockholders - basic and diluted ​ $ (50,608) ​ $ (27,308) Denominator: ​ ​ ​ ​ Weighted-average common stock outstanding - basic and diluted ​ 38,490,104 ​ 9,631,818 Net loss per share attributable to common stockholders - basic and diluted ​ $ (1.31) ​ $ (2.84) ​ ​ ​ ​ ​ ​ ​ ​ The Company’s potentially dilutive securities, which include preferred stock, unvested restricted common stock, unvested RSUs and stock options, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following from the computation of diluted net loss per share attributable to common stockholders at December 31, 2022 and 2021 because including them would have had an anti-dilutive effect: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Preferred Stock ​ — ​ — Unvested restricted stock ​ 311,825 830,046 Unvested RSUs ​ 31,650 ​ — Options to purchase common stock ​ 7,257,786 ​ 5,163,643 ​ ​ 7,601,261 5,993,689 ​ ​ ​ ​ ​ ​

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2022
Related Party Transactions
Related Party Transactions	14. Related Party Transactions Iain Dukes is a founding member of the Company and has served as a member of the Board since June 2018. From June 2018 until April 2021, Dr. Dukes served as the Company’s Chief Executive Officer under a consulting agreement, and from April 2021 until September 2021, Dr. Dukes served as the Executive Chairman. On September 15, 2021, Dr. Dukes transitioned into his role as Chairman of the Board. During the year ended December 31, 2021, Dr. Dukes earned compensation of $0.3 million, of which $54,000 was payable as of year-end. As of December 31, 2021, Dr. Dukes owned 388,324 shares of the Company’s common stock, and held options to purchase an additional 464,637 shares of common stock.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events
Subsequent Events	15. Subsequent Events Subsequent to December 31, 2022, the Company sold an aggregate of 4,816,301 shares of common stock pursuant to an “at-the-market” program for net proceeds of $49.1 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Summary of Significant Accounting Policies
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Theseus Pharmaceuticals, Inc. and Theseus Securities Corporation, which is a Massachusetts subsidiary. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Estimates and judgments are based on historical information and other market-specific or various relevant assumptions, including in certain circumstances, future projections, that management believes to be reasonable under the circumstances. Actual results could differ materially from estimates. Significant estimates and assumptions are used for, but not limited to, the accruals for research and development expenses, the incremental borrowing rate for determining the operating lease right-of-use (“ROU”) asset and lease liabilities, and for periods prior to the completion of the IPO, the determination of fair value of equity instruments, and the fair value of the preferred stock tranche rights and the anti-dilution right, and stock-based compensation expense.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, and marketable securities. Periodically, 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 have 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. Such deposits have and will continue to exceed federally insured limits. The Company has not experienced any losses on its cash deposits. The Company’s short-term and long-term marketable securities are invested in high grade securities with limited concentration in any one issuer, and as a result, the Company believes represent minimal credit risk.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company categorizes its assets and liabilities measured at fair value in accordance with ASC Topic 820, Fair Value Measurement ● Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities; ● Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability; or ● Level 3—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
Cash and Cash Equivalents	Cash and Cash Equivalents Cash includes cash in readily available checking accounts. Cash is carried at cost, which approximates its fair value. The Company considers all highly liquid marketable securities with original maturities of three months or less at the date of purchase to be cash equivalents. Cash equivalents are carried at fair market value based on quoted prices for identical assets.
Restricted Cash	Restricted Cash Restricted cash consists of a restricted cash deposit of $0.4 million which serves as collateral for a letter of credit issued to the landlord of the Company’s leased facility for a security deposit upon entering into the lease in September 2021. The Company classified this amount as restricted cash in the accompanying consolidated balance sheet within other assets as of December 31, 2022 and 2021.
Marketable Securities	Marketable Securities All marketable securities have been classified as “available-for-sale” and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Marketable securities with contractual maturities less than 12 months at the balance sheet date are considered short-term marketable securities. Those marketable securities with contractual maturities 12 months or greater at the balance sheet date are considered long-term marketable securities. Dividend and interest income are recognized in the Company’s consolidated statements of operations and comprehensive loss when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). The cost of the Company’s available-for-sale debt securities is adjusted for amortization of premium and accretion of discounts to maturity. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in statements of operations, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss).
Property and Equipment, net	Property and Equipment, net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets as follows: ​ ​ ​ ​ Estimated Useful Life (Years) Office equipment ​ 5 years Computer equipment and software ​ 3 years Furniture and fixtures ​ 7 years Leasehold improvements ​ Lesser of asset useful life or lease term ​ Costs for capital assets not yet placed into service are capitalized as construction-in-progress and are depreciated once placed into service. When an item is sold or retired, the costs and related accumulated depreciation are eliminated, and the resulting gain or loss, if any, is included in the consolidated statement of operations. Repairs and maintenance costs are expensed as incurred.
Leases	Leases Effective on January 1, 2021, the Company accounts for leases in accordance with ASC Topic 842, Leases A lease qualifies as a finance lease if any of the following criteria are met at the inception of the lease: (i) there is a transfer of ownership of the leased asset to the Company by the end of the lease term, (ii) the Company holds an option to purchase the leased asset that it is reasonably certain to exercise, (iii) the lease term is for a major part of the remaining economic life of the leased asset, (iv) the present value of the sum of lease payments equals or exceeds substantially all of the fair value of the leased asset, or (v) the nature of the leased asset is specialized to the point that it is expected to provide the lessor no alternative use at the end of the lease term. All other leases are recorded as operating leases. The Company enters into contracts that contain both lease and non-lease components. Non-lease components may include maintenance, utilities, and other operating costs. For all real estate asset classes, the Company combines the lease and non-lease components of fixed costs in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement of ROU assets and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs. Finance and operating lease assets and liabilities are recognized at the lease commencement date based on the present value of the lease payments over the lease term using the discount rate implicit in the lease. If the rate implicit is not readily determinable, the Company utilizes an estimate of its incremental borrowing rate based upon the available information at the lease commencement date. ROU assets are further adjusted for initial direct costs, prepaid rent, or incentives received. Operating lease payments are expensed using the straight-line method as an operating expense over the lease term. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Finance lease assets are amortized to depreciation expense using the straight-line method over the shorter of the useful life of the related asset or the lease term. Finance lease payments are bifurcated into (i) a portion that is recorded as interest expense and (ii) a portion that reduces the finance liability associated with the lease.
Impairment of Long-lived Assets	Impairment of Long-lived Assets Long-lived assets consist of property and equipment. The Company reviews the recoverability of its long-lived assets, including the related useful lives, whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset might not be recoverable, based on undiscounted cash flows. If such assets are considered to be impaired, an impairment loss is recognized and is measured as the amount by which the carrying amount of the assets exceed their estimated fair value, which is measured based on the projected discounted future net cash flows arising from the assets. There were no impairments for the years ended December 31, 2022 and 2021.
Accrued Research and Development Costs	Accrued Research and Development Costs The Company records accrued liabilities for estimated costs of research and development activities conducted by service providers for sponsored research, preclinical studies and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued expenses in the accompanying consolidated balance sheets and within research and development expense in the accompanying statements of operations. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with service providers. The Company makes judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities. The Company has not experienced any material differences between accrued costs and actual costs incurred since its inception.
Deferred Issuance Costs	Deferred Issuance Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred issuance costs until such financings are consummated. After consummation of such an equity financing, these costs are recorded as a reduction of the proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred issuance costs, currently recorded within other assets, will be expensed immediately as a charge to operating expenses in the statements of operations and comprehensive loss. On October 6, 2021, the Company completed its IPO. Accordingly, the Company recognized deferred issuance costs of $3.8 million as a reduction from the gross proceeds associated with the closing of the IPO through additional paid-in capital in the accompanying consolidated balance sheet as of December 31, 2021.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research and development activities on the Company’s behalf.
Patent Costs	Patent Costs The Company expenses all costs as incurred in connection with patent applications, including direct application fees, and the legal and consulting expenses related to making such applications, and such costs are included in general and administrative expenses within the Company’s statements of operations.
Stock-based Compensation	Stock-based Compensation The Company’s stock-based compensation plan grants awards to employees and non-employees that may include stock options, restricted stock awards, restricted stock units, and other stock-based awards, and recognizes the expense in the consolidated statement of operations and comprehensive loss based on their grant date fair values. The fair values of stock options are estimated on the date of grant using the Black-Scholes option-pricing model. The fair values of restricted stock awards and restricted stock units are based on the fair value of the Company’s common stock on the date of grant. The estimated grant date fair value of stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the award. The Company has performance-based vesting conditions in some of its awards, and all performance-based milestones have been met or waived as of December 31, 2021. The Company accounts for awards granted to non-employees using the same treatment as awards granted to employees. The Company recognizes forfeitures as they occur. Estimating the fair value of stock options using the Black-Scholes option-pricing model requires the input of subjective assumptions including: the fair value of common stock, the expected term of stock options, the expected volatility of common stock, the risk-free interest rate for a period that approximates the expected term of stock options, and expected dividend yield. The fair value is the closing price of the Company’s common stock on the Nasdaq Global Select Market as reported on the date of grant. The expected term is estimated using the “simplified” method for awards that qualify as “plain-vanilla”, which deems the expected term to be the midpoint between the vesting date and the contractual life of the stock-based awards. For expected volatility, the Company based its computation on the historical volatility of a representative group of public companies with similar characteristics, including stage of product development, life science industry focus, length of trading history and similar vesting provisions. The risk-free interest rate is based on the US Treasury yield in effect at the time of grant for zero-coupon US Treasury notes with maturities approximately equal to the expected term of the awards. The expected dividend yield is assumed to be zero as the Company has never paid cash dividends on its common stock and has no plans to pay cash dividends on common stock in the visible future. Certain assumptions used in the Black-Scholes option-pricing model represent management’s best estimates and involve a number of variables, uncertainties and assumptions and the application of management’s judgment, as they are inherently subjective. If any assumptions change, the Company’s stock-based compensation expense could be materially different in the future. The Company’s equity incentive plan allows for but does not require the inclusion of early exercise provisions in individual awards. The unvested shares of any restricted stock awards are held in escrow as the stock award vests or until award holder termination, whichever occurs first. In the event of a termination, the Company has the right of repurchase, at its option, the portion of unvested stock awards from the terminated award holder at their original issuance price. For all unvested stock option awards for which the award recipient has transferred cash to the Company prior to the vesting date, a liability is established related to the cash received for the unvested portion of the stock awards, which represents the Company’s obligation if all award holders were to be terminated. Prior to the Company’s IPO, the estimated fair value of its common stock was determined by the Board of Directors as of the date of each option grant, with input from management, considering the most recently available third-party valuations of common stock and the Board’s assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent valuation through the date of the grant. Historically, these independent third-party valuations of the Company’s equity instruments were performed contemporaneously with identified value inflection points. 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 available methods for allocating the enterprise value across classes of series of capital stock in determining the fair value of the Company’s common stock at each valuation date. The Company issues rights to employees to purchase common stock under the Theseus Pharmaceuticals, Inc. 2021 Employee Stock Purchase Plan (the “ESPP”). The purchase price of common stock under the Company’s ESPP is equal to 85% of the lesser of (i) the fair market value per share of common stock on the first trading day of an offering period and (ii) the fair market value per share of common stock on the purchase date. The fair value of the discounted purchases made under the ESPP is calculated using the Black-Scholes option-pricing model. The fair value of the look-back provision plus the 15% discount is recognized as compensation expense over the 180-day
Net Loss Per Share	Net Loss Per Share The Company follows the two-class method when computing net loss allocable to common securities per share as the Company has issued shares that meet the definition of participating securities, see Note 13 for additional information. During periods of loss, there is no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company. Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding during the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, diluted net loss per share attributable to common stockholders is calculated by dividing net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding after giving consideration to the dilutive effect of convertible preferred stock, restricted common stock, restricted stock units and stock options that are outstanding during the period. The Company has generated a net loss in all periods presented, therefore the basic and diluted net loss per share attributable to common stockholders are the same as the inclusion of the potentially dilutive securities would be anti-dilutive.
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock Prior to the Company’s IPO, the Company’s redeemable convertible preferred stock was classified as temporary equity in the consolidated balance sheets and excluded from stockholders’ equity (deficit) as the potential redemption of such stock was outside the Company’s control. Upon the completion of the Company’s IPO on October 6, 2021, all outstanding shares of the Company’s redeemable convertible preferred stock converted into shares of the Company’s common stock.
Income Taxes	Income Taxes Income taxes for the Company are recorded in accordance with ASC Topic 740, Income Taxes The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions. The tax benefits recorded are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is “more likely than not” to be realized following resolution of any uncertainty related to the tax benefit, assuming that the matter in question will be raised by the tax authorities. The Company’s policy is to recognize interest and penalties accrued on any uncertain tax positions, if any, as a component of income tax expense in its statements of operations and comprehensive loss.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders, including unrealized gains and losses on marketable securities. For the year ended December 31, 2022, the unrealized losses on marketable securities represent the only component of other comprehensive loss that is excluded from the reported net loss. For the year ended December 31, 2021, there were no differences between net loss and comprehensive loss.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker (“CODM”) in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company has determined it operates in a single operating segment and has one reportable segment. All long-lived assets of the Company reside in the US.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial statements and disclosures. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value of Financial Assets and Liabilities
Schedule of assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2022 ​ LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Cash equivalents: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds $ 6,846 ​ $ — ​ $ — ​ $ 6,846 Commercial paper ​ ​ — ​ ​ 3,989 ​ ​ — ​ ​ 3,989 Marketable Securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper ​ ​ — ​ ​ 25,187 ​ ​ — ​ ​ 25,187 Corporate debt securities ​ ​ — ​ ​ 45,673 ​ ​ — ​ ​ 45,673 Asset-backed securities ​ ​ — ​ ​ 13,574 ​ ​ — ​ ​ 13,574 Government securities ​ ​ — ​ ​ 32,757 ​ ​ — ​ ​ 32,757 Total financial assets ​ $ 6,846 ​ $ 121,180 ​ $ — ​ $ 128,026 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2022
Marketable Securities
Schedule of cost, gross unrealized holding gains, gross unrealized holding losses and fair value of investments by types and classes of security	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, 2022 ​ ​ MATURITY ​ AMORTIZED ​ UNREALIZED ​ UNREALIZED ​ FAIR ​ IN YEARS COST GAIN LOSS VALUE Commercial paper ​ less than 1 ​ $ 25,187 ​ $ — ​ $ — ​ $ 25,187 Corporate debt securities ​ less than 1 ​ ​ 39,071 ​ ​ 9 ​ ​ (185) ​ ​ 38,895 Asset-backed securities ​ less than 1 ​ ​ 8,555 ​ ​ 2 ​ ​ (10) ​ ​ 8,547 Government securities ​ less than 1 ​ ​ 30,892 ​ ​ 8 ​ ​ (155) ​ ​ 30,745 Short-term marketable securities ​ ​ ​ $ 103,705 ​ $ 19 ​ $ (350) ​ $ 103,374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt securities ​ 1 - 2 ​ ​ 6,783 ​ ​ — ​ ​ (5) ​ ​ 6,778 Asset backed securities ​ 1 - 2 ​ ​ 5,074 ​ ​ — ​ ​ (47) ​ ​ 5,027 Government securities ​ 1 - 2 ​ ​ 2,015 ​ ​ — ​ ​ (3) ​ ​ 2,012 Long-term marketable securities ​ ​ ​ $ 13,872 ​ $ — ​ $ (55) ​ $ 13,817 ​

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2022
Property and Equipment
Schedule of property and equipment	Property and equipment, net consisted of the following as of December 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ ​ 2022 2021 Computer equipment ​ $ 50 ​ $ 12 Furniture and fixtures ​ ​ 341 ​ ​ — Office equipment ​ ​ 76 ​ ​ — Property and equipment ​ ​ 467 ​ ​ 12 Less: accumulated depreciation ​ (51) ​ (1) Property and equipment, net ​ $ 416 ​ $ 11 ​ ​ ​ ​ ​ ​ ​ ​

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Accrued Expenses
Schedule of accrued expenses	Accrued expenses consisted of the following as of December 31, 2022 and 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Accrued research and development ​ $ 1,498 ​ $ 233 Accrued legal ​ ​ 164 ​ ​ 199 Accrued compensation and benefits ​ ​ 3,130 ​ ​ 1,353 Accrued other ​ ​ 273 ​ ​ 313 Restricted stock liability, current ​ ​ 349 ​ ​ 580 Total accrued expenses and other current liabilities ​ $ 5,414 ​ $ 2,678 ​ ​ ​ ​ ​ ​ ​

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases
Schedule of future minimum payments required under the lease	​ ​ ​ ​ ​ ​ Fiscal Year ​ Operating Lease 2023 ​ ​ $ 774 2024 ​ ​ ​ 797 2025 ​ ​ ​ 821 2026 ​ ​ ​ 846 Thereafter ​ ​ ​ 1,996 Total future minimum lease payments ​ ​ ​ 5,234 Less: imputed interest ​ ​ ​ (1,255) Present value of lease liabilities ​ ​ $ 3,979

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Stock-Based Compensation
Schedule of stock option valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Risk-free interest rate ​ 1.60% - 4.20% ​ 1.07% Expected term (in years) ​ 1.03 - 6.08 ​ 5.2 - 6.1 Expected volatility ​ 78.00% - 90.51% ​ 75.58% - 83.56% Expected dividend yield ​ 0.00% ​ 0.00% ​ ​ ​ ​ ​ ​
Schedule of summary of option activity	A summary of option activity under the Plans during the years ended December 31, 2022 and 2021 is as follows (in thousands except share, per share data and contractual terms): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE WEIGHTED-AVERAGE ​ ​ ​ ​ ​ PER-SHARE ​ REMAINING ​ AGGREGATE ​ ​ SHARES ​ EXERCISE PRICE ​ CONTRACTUAL TERM ​ INTRINSIC VALUE Outstanding as of December 31, 2021 ​ 5,163,643 ​ $ 4.31 9.29 ​ $ 44,463 Granted ​ 2,366,200 ​ 10.05 ​ Forfeited ​ (272,057) ​ (8.29) ​ ​ Outstanding as of December 31, 2022 ​ 7,257,786 ​ $ 5.95 8.58 ​ 10,750.63 Options vested and exercisable as of December 31, 2022 ​ 2,367,914 ​ $ 3.59 8.25 ​ $ 5,736.58 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of RSU activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE ​ ​ ​ ​ PER-SHARE GRANT-DATE ​ SHARES FAIR VALUE Unvested shares at December 31, 2021 — ​ $ — Granted 35,900 ​ 11.21 Forfeited ​ (4,250) ​ ​ 11.21 Unvested shares at December 31, 2022 31,650 ​ $ 11.21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of restricted common stock activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ WEIGHTED-AVERAGE ​ ​ ​ ​ PER-SHARE GRANT-DATE ​ ​ SHARES ​ FAIR VALUE Unvested shares at December 31, 2021 830,046 ​ $ 2.85 Vesting of restricted common stock (518,221) ​ 2.18 Unvested shares at December 31, 2022 311,825 ​ $ 3.96 ​ ​ ​ ​ ​ ​ ​
Schedule of stock-based compensation expense	Total stock-based compensation expense recorded as research and development and general and administrative expenses, respectively, for employees, directors and non-employees during the years ended December 31, 2022 and 2021 was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Research and development ​ $ 6,612 ​ $ 2,250 General and administrative ​ ​ 4,800 ​ ​ 2,111 ​ ​ $ 11,412 ​ $ 4,361 ​ ​ ​ ​ ​ ​ ​ ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Taxes
Schedule of effective income tax rate differed from federal statutory rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Tax effected at statutory rate ​ 21.0 % ​ 21.0 % State taxes ​ ​ 5.6 ​ ​ 5.3 ​ Stock compensation ​ ​ (1.7) ​ ​ (3.0) ​ Non-deductible expenses ​ ​ (0.9) ​ ​ — ​ Research and development credits ​ ​ 3.6 ​ ​ 3.3 ​ ​ ​ ​ 27.6 ​ ​ 26.6 ​ Change in valuation allowance ​ ​ (27.6) ​ ​ (26.6) ​ Total ​ ​ — % ​ — % ​ ​ ​ ​ ​ ​ ​ ​ ​
Schedule of deferred tax assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Deferred Tax Assets ​ ​ ​ ​ ​ ​ Net operating loss carryforwards $ 12,957 $ 9,420 Research and development credits ​ ​ 2,670 ​ ​ 916 Stock-based compensation expense ​ ​ 1,506 ​ ​ 116 Accruals and reserves ​ ​ 717 ​ ​ 367 Intangible assets ​ ​ 647 ​ ​ 702 Operating lease liability ​ ​ 1,087 ​ ​ — Capitalized research and development ​ ​ 7,238 ​ ​ — Gross deferred tax assets ​ ​ 26,822 ​ ​ 11,521 Deferred Tax Liabilities ​ ​ ​ ​ ​ ​ Depreciation ​ $ (114) ​ $ (3) Operating lease right-of-use asset ​ ​ (1,184) ​ ​ — Gross deferred tax liabilities ​ ​ (1,298) ​ ​ (3) Net deferred tax assets before valuation allowance ​ ​ 25,524 ​ ​ 11,518 Valuation allowance ​ ​ (25,524) ​ ​ (11,518) Net deferred tax asset ​ $ — $ — ​ ​ ​ ​ ​ ​ ​ ​

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Net Loss Per Share
Schedule of basic and diluted loss per share	Basic and diluted loss per share is computed by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ YEAR ENDED DECEMBER 31, ​ 2022 2021 Numerator: ​ ​ ​ ​ ​ ​ Net loss ​ $ (50,608) ​ $ (27,308) Net loss attributable to common stockholders - basic and diluted ​ $ (50,608) ​ $ (27,308) Denominator: ​ ​ ​ ​ Weighted-average common stock outstanding - basic and diluted ​ 38,490,104 ​ 9,631,818 Net loss per share attributable to common stockholders - basic and diluted ​ $ (1.31) ​ $ (2.84) ​ ​ ​ ​ ​ ​ ​ ​
Schedule of antidilutive securities excluded from computation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ DECEMBER 31, ​ 2022 2021 Preferred Stock ​ — ​ — Unvested restricted stock ​ 311,825 830,046 Unvested RSUs ​ 31,650 ​ — Options to purchase common stock ​ 7,257,786 ​ 5,163,643 ​ ​ 7,601,261 5,993,689 ​ ​ ​ ​ ​

Nature of the Business (Details

Nature of the Business (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Oct. 25, 2021 USD ($) $ / shares shares	Oct. 12, 2021 $ / shares shares	Sep. 27, 2021	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares
Reverse split			1.32286
Aggregate net offering proceeds				$ 182
Common stock, shares authorized | shares		500,000,000		500,000,000	500,000,000
Redeemable convertible preferred stock, shares authorized | shares		50,000,000
Accumulated deficit				$ (112,186)	$ (61,578)
Net loss				(50,608)	(27,308)
Net cash used in operations				(32,945)	(27,193)
Cash and cash equivalents				94,605	$ 244,662
Amount of cash and cash equivalents, and investments				$ 211,800
IPO
Shares issued | shares		10,000,200
Share price per share | $ / shares		$ 16
Aggregate net offering proceeds	$ 162,500
Shares converted to common stock | shares		25,475,905
Over-Allotment Option
Share price per share | $ / shares	$ 16
Number of shares | shares	1,171,990

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)
Property, Plant and Equipment [Line Items]
Restricted cash deposit			$ 400
Deferred issuance costs		$ 3,800
Expected dividend yield	0%	0%
Number of reportable segment | segment	1
Impairments	$ 0	$ 0
2021 ESPP
Property, Plant and Equipment [Line Items]
Percentage of purchase price of common stock ,	85%
Percentage of discount from market price	15%
Purchase period of shares under share based payment arrangement	180 days
Office Equipment
Property, Plant and Equipment [Line Items]
Useful life (in years)	5 years
Computed equipment and software
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life (in years)	7 years

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities - Recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets
Liabilities measured at fair value		$ 0
Recurring
Assets
Total financial assets	$ 128,026
Recurring | Commercial Paper
Assets
Cash equivalents	3,989
Total financial assets	25,187
Recurring | Corporate Debt Securities
Assets
Total financial assets	45,673
Recurring | Asset-backed Securities
Assets
Total financial assets	13,574
Recurring | Government Securities
Assets
Total financial assets	32,757
Recurring | Money Market Funds
Assets
Cash equivalents	6,846
Recurring | Level 1
Assets
Total financial assets	6,846
Recurring | Level 1 | Money Market Funds
Assets
Cash equivalents	6,846
Recurring | Level 2
Assets
Total financial assets	121,180
Recurring | Level 2 | Commercial Paper
Assets
Cash equivalents	3,989
Total financial assets	25,187
Recurring | Level 2 | Corporate Debt Securities
Assets
Total financial assets	45,673
Recurring | Level 2 | Asset-backed Securities
Assets
Total financial assets	13,574
Recurring | Level 2 | Government Securities
Assets
Total financial assets	$ 32,757

Marketable Securities (Details)

Marketable Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Marketable Securities
Short-term marketable securities	$ 103,374
Long-term marketable securities	13,817
Amount of fair value investments due to credit-related factors	0
Short-Term Investments
Marketable Securities
Amortized cost	103,705
Unrealized gain	19
Unrealized loss	(350)
Short-term marketable securities	103,374
Long-Term Investments
Marketable Securities
Amortized cost	13,872
Unrealized loss	(55)
Long-term marketable securities	13,817
Commercial Paper | Short-Term Investments
Marketable Securities
Amortized cost	25,187
Short-term marketable securities	25,187
Corporate Debt Securities | Short-Term Investments
Marketable Securities
Amortized cost	39,071
Unrealized gain	9
Unrealized loss	(185)
Short-term marketable securities	38,895
Corporate Debt Securities | Long-Term Investments
Marketable Securities
Amortized cost	6,783
Unrealized loss	(5)
Long-term marketable securities	6,778
Asset-backed Securities | Short-Term Investments
Marketable Securities
Amortized cost	8,555
Unrealized gain	2
Unrealized loss	(10)
Short-term marketable securities	8,547
Asset-backed Securities | Long-Term Investments
Marketable Securities
Amortized cost	5,074
Unrealized loss	(47)
Short-term marketable securities	5,027
Government Securities | Short-Term Investments
Marketable Securities
Amortized cost	30,892
Unrealized gain	8
Unrealized loss	(155)
Short-term marketable securities	30,745
Government Securities | Long-Term Investments
Marketable Securities
Amortized cost	2,015
Unrealized loss	(3)
Short-term marketable securities	$ 2,012

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property and Equipment
Property and equipment, gross	$ 467	$ 12
Less: accumulated depreciation	(51)	(1)
Property and equipment, net	416	11
Computer equipment
Property and Equipment
Property and equipment, gross	50	$ 12
Furniture and Fixtures
Property and Equipment
Property and equipment, gross	341
Office Equipment
Property and Equipment
Property and equipment, gross	$ 76

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property and Equipment
Depreciation expense	$ 50,000	$ 2,000
Impairments recorded to date	$ 0	$ 0

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued Expenses
Accrued research and development	$ 1,498	$ 233
Accrued legal	164	199
Accrued compensation and benefits	3,130	1,353
Accrued other	273	313
Restricted stock liability, current	349	580
Total accrued expenses and other current liabilities	$ 5,414	$ 2,678

License Agreement (Details)

License Agreement (Details)	12 Months Ended
	Dec. 31, 2022
License agreement with ARIAD
License Agreements [Line Items]
Minimum threshold period of royalty term	10 years

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands		12 Months Ended
	Sep. 16, 2021 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Leases
Short-term lease cost		$ 200	$ 200
Office space leased | ft²	7,351
Lease term	7 years
ROU Asset	$ 4,700	4,334
Operating lease liability	$ 4,700	$ 3,979
Renewal term	5 years
Initial base rent	$ 800
Lease subject to annual increase (as percentage)	3%
Security deposit in the form of line of credit	$ 400
Weighted-average remaining lease term		6 years 3 months 18 days
Weighted-average discount rate		9.10%

Leases - Future minimum payment

Leases - Future minimum payments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Sep. 16, 2021
Leases
2023	$ 774
2024	797
2025	821
2026	846
Thereafter	1,996
Total future minimum lease payments	5,234
Less: imputed interest	(1,255)
Present value of lease liabilities	$ 3,979	$ 4,700

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
401(k) Plan
Commitments and Contingencies
Amount employer contributions made to the 401(k) Plan	$ 0.4	$ 0

Stockholders' Equity (Details)

Stockholders' Equity (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) Vote $ / shares shares	Dec. 31, 2021 $ / shares shares	Oct. 12, 2021 shares
Preferred stock, par value | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred Stock, Shares Outstanding	0	0
Common stock, authorized	500,000,000	500,000,000	500,000,000
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Number of votes per common stock | Vote	1
Common stock, cash dividend | $	$ 0
Shares of Restricted Common Stock
Vesting period	5 years

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock-Based Compensation
Options to purchase common stock, exercised	$ 581
Proceeds from options exercised		$ 1,395
Stock Option
Stock-Based Compensation
Stock-based compensation expense	$ 10,800
Shares of Restricted Common Stock
Stock-Based Compensation
Vesting period	5 years
2021 Plan
Stock-Based Compensation
Shares reserved under the Plan	9,132,930	9,094,083
Shares available for future grant under the Plan	1,843,494	3,930,440
Expiration period	10 years
Vesting period	4 years
Options to purchase common stock, exercised (in shares)	201,793	345,930
Additional early exercises of options	0
2021 Plan | Maximum
Stock-Based Compensation
Percent of annual increase in shares authorized	5%
2021 Plan | Shares of Restricted Common Stock
Stock-Based Compensation
Vesting period	5 years
2021 ESPP
Stock-Based Compensation
Shares available for future grant under the Plan	368,204
Employee Stock Purchase Plan	The ESPP enables eligible employees to purchase shares of common stock of the Company at the end of each offering period at a price equal to 85% of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant date of purchase
Options to purchase common stock, exercised	$ 800	$ 1,400
Common stock reserved for issuance	400,000
Percentage increase of common stock reserved for issuance	1%
Percentage of purchase price of common stock ,	85%
Shares of common stock issued under the ESPP	31,796
Cash received from purchases under the ESPP	$ 200
Share price per share	$ 5.86
Stock-based compensation expense	$ 200

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Valuation (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock-Based Compensation
Risk-free interest rate		1.07%
Expected volatility, Minimum	78%	75.58%
Expected volatility, Maximum	90.51%	83.56%
Expected dividend yield	0%	0%
Minimum
Stock-Based Compensation
Risk-free interest rate	1.60%
Expected term (in years)	1 year 10 days	5 years 2 months 12 days
Maximum
Stock-Based Compensation
Risk-free interest rate	4.20%
Expected term (in years)	6 years 29 days	6 years 1 month 6 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of option activity (Details) - Stock Option - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Shares
Outstanding as of beginning of period (in shares)	5,163,643
Granted (in shares)	2,366,200
Forfeited (in shares)	(272,057)
Outstanding as of end of period (in shares)	7,257,786	5,163,643
Options vested and exercisable (in shares)	2,367,914
Weighted-average per-share exercise price
Outstanding as of beginning of period (in per share)	$ 4.31
Granted (in per share)	10.05
Forfeited (in per share)	(8.29)
Outstanding as of end of period (in per share)	5.95	$ 4.31
Options vested and exercisable (in per share)	$ 3.59
Additional Disclosures
Weighted-average remaining contractual term	8 years 6 months 29 days	9 years 3 months 14 days
Weighted-average remaining contractual term, vested and exercisable	8 years 3 months
Aggregate intrinsic value	$ 10,750.63	$ 44,463,000
Aggregate intrinsic value, vested and exercisable	$ 5,736.58
Weighted-average per share grant date fair value of options granted	$ 6.93
Stock-based compensation expense	$ 10,800,000
Unrecognized stock-based compensation expense related to unvested stock options	$ 23,800,000
Recognition period	2 years 6 months
Total fair value of options vested	$ 10,500,000	$ 2,400,000

Stock-Based Compensation - Shar

Stock-Based Compensation - Shares of Restricted Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Shares of Restricted Common Stock
Shares
Unvested shares, Beginning balance (in shares)	830,046
Vested	(518,221)
Unvested shares, Ending balance (in shares)	311,825	830,046
Weighted-average per-share grant-date fair value
Unvested shares, Beginning balance (in per share)	$ 2.85
Vested	2.18
Unvested shares, Ending balance (in per share)	$ 3.96	$ 2.85
Unrecognized stock-based compensation expense related to unvested restricted stock	$ 1.2
Recognition period	1 year 8 months 12 days
Restricted Stock Units
Shares
Granted (in shares)	35,900	0
Forfeited (in shares)	(4,250)
Unvested shares, Ending balance (in shares)	31,650
Weighted-average per-share grant-date fair value
Granted (in per shares)	$ 11.21
Forfeited (in per shares)	11.21
Unvested shares, Ending balance (in per share)	$ 11.21
Vesting schedule	The Company issues RSUs that generally vest over a four-year period with 25% of the RSUs vesting one year from the vesting commencement date, and the remainder vesting quarterly thereafter over the following 36 months. Any unvested shares underlying an RSU will be forfeited upon termination of services
Unrecognized stock-based compensation expense related to unvested restricted stock	$ 0.2
Recognition period	3 years 2 months 12 days

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stock-Based Compensation
Stock-based compensation expense	$ 11,412	$ 4,361
Amount stock-based compensation expense due to modification of terms of certain equity awards held by a departing employee	1,800
Research and development
Stock-Based Compensation
Stock-based compensation expense	6,612	2,250
General and administrative
Stock-Based Compensation
Stock-based compensation expense	$ 4,800	$ 2,111

Income Taxes - Schedule of effe

Income Taxes - Schedule of effective income tax rate differed from federal statutory rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax effected at statutory rate	21%	21%
State taxes	5.60%	5.30%
Stock compensation	(1.70%)	(3.00%)
Non-deductible expenses	(0.90%)
Research and development credits	3.60%	3.30%
Other	27.60%	26.60%
Change in valuation allowance	(27.60%)	(26.60%)

Income Taxes - Schedule of defe

Income Taxes - Schedule of deferred tax assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Net operating loss carryforward	$ 12,957	$ 9,420
Research and development credits	2,670	916
Stock-based compensation	1,506	116
Accruals and reserves	717	367
Intangible assets	647	702
Operating lease liability	1,087
Capitalized research and development	7,238
Gross deferred tax assets	26,822	11,521
Depreciation	(114)	(3)
Operating lease right-of-use asset	(1,184)
Gross deferred tax liabilities	1,298	3
Net deferred tax assets before valuation allowance	25,524	11,518
Valuation allowance	$ (25,524)	$ (11,518)

Income Taxes - Additional infor

Income Taxes - Additional information (Details) - USD ($)	12 Months Ended		24 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 25,524,000	$ 11,518,000	$ 25,524,000
Change in valuation allowance	14,000,000	7,300,000
Research and development credits	$ 2,670,000	$ 916,000	2,670,000
Estimated interest or penalties recognized			0
Minimum
Operating Loss Carryforwards [Line Items]
Amortization period of research and experimental expenditures	5 years
Maximum
Operating Loss Carryforwards [Line Items]
Amortization period of research and experimental expenditures	15 years
Federal
Operating Loss Carryforwards [Line Items]
State research and development credit carryforwards yet to expire	$ 47,000,000		47,000,000
Research and development credits	1,800,000		1,800,000
State
Operating Loss Carryforwards [Line Items]
State research and development credit carryforwards yet to expire	48,900,000		48,900,000
Research and development credits	$ 1,000,000		$ 1,000,000

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and diluted loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (50,608)	$ (27,308)
Net loss attributable to common stockholders - basic	(50,608)	(27,308)
Net loss attributable to common stockholders - diluted	$ (50,608)	$ (27,308)
Denominator:
Weighted-average common stock outstanding-basic	38,490,104	9,631,818
Weighted-average common stock outstanding- diluted	38,490,104	9,631,818
Net loss per share attributable to common stockholders-basic	$ (1.31)	$ (2.84)
Net loss per share attributable to common stockholders- diluted	$ (1.31)	$ (2.84)

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Anti-dilutive Effect
Shares excluded since there inclusion would be anti-dilutive	7,601,261	5,993,689
Shares of Restricted Common Stock
Anti-dilutive Effect
Shares excluded since there inclusion would be anti-dilutive	311,825	830,046
Restricted Stock Units
Anti-dilutive Effect
Shares excluded since there inclusion would be anti-dilutive	31,650
Stock Option
Anti-dilutive Effect
Shares excluded since there inclusion would be anti-dilutive	7,257,786	5,163,643

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2022
Related Party Transactions
Common stock, shares issued	38,702,650	38,734,446
Chief Executive Officer
Related Party Transactions
Amount of earned compensation	$ 300,000
Amount of earned compensation payable	$ 54,000
Common stock, shares issued	388,324
Options to purchase additional shares of common stock (in shares)	464,637

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands				12 Months Ended
	Jan. 01, 2023	Oct. 25, 2021	Oct. 12, 2021	Dec. 31, 2022
Subsequent Events
Aggregate net offering proceeds				$ 182
IPO
Subsequent Events
Shares issued			10,000,200
Aggregate net offering proceeds		$ 162,500
Subsequent event | ATM Program
Subsequent Events
Shares issued	4,816,301
Aggregate net offering proceeds	$ 49,100