Q32 Bio (QTTB) S-1 19 Apr 24 IPO registration Financial data

Cover Page

Cover Page	12 Months Ended
	Dec. 31, 2023
Document Information [Line Items]
Document Type	S-1
Amendment Flag	false
Entity Registrant Name	Q32 BIO INC.
Entity Central Index Key	0001661998
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3468154
Entity Address, Address Line One	830 Winter Street
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	781
Local Phone Number	999-0232
Entity Primary SIC Number	2834
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Business Contact [Member]
Document Information [Line Items]
Contact Personnel Name	Jodie Morrison
Entity Address, Address Line One	830 Winter Street
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	781
Local Phone Number	999-0232

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 25,617	$ 43,893
Prepaid expenses and other current assets	3,099	2,960
Total current assets	28,716	46,853
Property and equipment, net	1,782	2,276
Right-of-use asset, operating leases	6,301	6,890
Restricted cash and restricted cash equivalents	5,647	5,647
Other noncurrent assets	4,611	108
Total assets	47,057	61,774
Current liabilities:
Accounts payable	3,468	1,435
Accrued expenses and other current liabilities	9,763	9,497
Venture debt, current portion	878	0
Convertible notes	0	32,402
Deferred revenue, current portion	0	14,531
Total current liabilities	14,109	57,865
Deferred revenue, net of current portion	0	11,318
Lease liability, net of current portion	6,248	6,786
Venture debt, net of current portion	4,581	5,072
Convertible notes	38,595	0
Other noncurrent liabilities	55,000	0
Total liabilities	118,533	81,041
Commitments and contingencies (Note 7)
Preferred Stock	111,445	111,445
Stockholders' deficit:
Common stock, $0.0001 par value; 225,000,000 and 141,900,000 shares authorized, 7,472,835 and 7,139,216 shares issued and outstanding at December 31, 2023 and 2022, respectively	1	1
Additional paid-in capital	4,159	2,625
Accumulated deficit	(187,081)	(133,338)
Total stockholders' deficit	(182,921)	(130,712)
Total liabilities, convertible preferred stock and stockholders' deficit	47,057	61,774
Series A convertible preferred stock [Member]
Current liabilities:
Preferred Stock	47,458	47,458
Series A-1 convertible preferred stock [Member]
Current liabilities:
Preferred Stock	4,132	4,132
Series B convertible preferred stock [Member]
Current liabilities:
Preferred Stock	$ 59,855	$ 59,855

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Common stock par value per share	$ 0.0001	$ 0.0001
Common stock shares authorized	225,000,000	141,900,000
Common stock shares issued	7,472,835	7,139,216
Common stock shares outstanding	7,472,835	7,139,216
Series A convertible preferred stock [Member]
Preferred stock par value per share	$ 0.0001	$ 0.0001
Preferred stock shares authorized	47,628,788	47,628,788
Preferred stock shares issued	47,628,788	47,628,788
Preferred stock shares outsstanding	47,628,788	47,628,788
Preferred stock liquidation preference	$ 47,629
Series A-1 convertible preferred stock [Member]
Preferred stock par value per share	$ 0.0001	$ 0.0001
Preferred stock shares authorized	6,500,000	6,500,000
Preferred stock shares issued	6,500,000	6,500,000
Preferred stock shares outsstanding	6,500,000	6,500,000
Preferred stock liquidation preference	$ 5,753
Series B convertible preferred stock [Member]
Preferred stock par value per share	$ 0.0001	$ 0.0001
Preferred stock shares authorized	54,689,627	54,689,627
Preferred stock shares issued	54,689,627	54,689,627
Preferred stock shares outsstanding	54,689,627	54,689,627
Preferred stock liquidation preference	$ 60,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Collaboration arrangement revenue	$ (6,651)	$ 6,651
Operating expenses:
Research and development	31,729	35,814
General and administrative	9,875	10,062
Total operating expenses	41,604	45,876
Loss from operations	(48,255)	(39,225)
Change in fair value of convertible notes	(6,193)	(2,402)
Other income (expense), net	1,023	(1,120)
Total other income (expense), net	(5,170)	(3,522)
Loss before provision for income taxes	(53,425)	(42,747)
Provision for income taxes	(318)	(62)
Net loss and comprehensive loss	(53,743)	(42,809)
Net loss attributable to common stockholders, Basic	(53,743)	(42,809)
Net loss attributable to common stockholders, Diluted	$ (53,743)	$ (42,809)
Weighted-average common shares, Basic	7,253,978	7,025,420
Weighted-average common shares, Diluted	7,253,978	7,025,420
Net loss per share attributable to common stockholders, Basic	$ (7.41)	$ (6.09)
Net loss per share attributable to common stockholders, Diluted	$ (7.41)	$ (6.09)

CONSOLIDATED STATEMENTS OF CONV

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Total	Series A convertible preferred stock [Member]	Series A-1 convertible preferred stock [Member]	Series B convertible preferred stock [Member]	Preferred Stock [Member] Series A convertible preferred stock [Member]	Preferred Stock [Member] Series A-1 convertible preferred stock [Member]	Preferred Stock [Member] Series B convertible preferred stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2021					$ 47,458	$ 4,132	$ 59,855
Beginning balance, Shares at Dec. 31, 2021					47,628,788	6,500,000	54,689,627	6,828,125
Beginning balance at Dec. 31, 2021	$ (89,210)							$ 1	$ 1,318	$ (90,529)
Exercise of stock options, Shares								307,859
Exercise of stock options	69								69
Vesting of restricted stock, Shares								3,232
Stock-based compensation expense	1,238								1,238
Net loss	(42,809)									(42,809)
Ending balance, Shares at Dec. 31, 2022		47,628,788	6,500,000	54,689,627	47,628,788	6,500,000	54,689,627
Ending balance at Dec. 31, 2022					$ 47,458	$ 4,132	$ 59,855
Ending balance, Shares at Dec. 31, 2022								7,139,216
Ending balance at Dec. 31, 2022	(130,712)							$ 1	2,625	(133,338)
Exercise of stock options, Shares								333,619
Exercise of stock options	106								106
Stock-based compensation expense	1,428								1,428
Net loss	(53,743)									(53,743)
Ending balance, Shares at Dec. 31, 2023		47,628,788	6,500,000	54,689,627	47,628,788	6,500,000	54,689,627
Ending balance at Dec. 31, 2023					$ 47,458	$ 4,132	$ 59,855
Ending balance, Shares at Dec. 31, 2023								7,472,835
Ending balance at Dec. 31, 2023	$ (182,921)							$ 1	$ 4,159	$ (187,081)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (53,743)	$ (42,809)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt discount and issuance costs	87	100
Depreciation expense	499	370
Loss on disposal of property and equipment	0	23
Stock-based compensation expense	1,428	1,238
Non-cash lease expense	544	776
Change in fair value of convertible notes	6,193	2,402
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(94)	(1,209)
Other noncurrent assets	(4,503)	195
Accounts payable	2,033	(1,241)
Operating lease liability	(471)	(409)
Accrued expenses and other current liabilities	199	3,758
Contingent liability	55,000	0
Deferred revenue	(25,849)	25,849
Net cash used in operating activities	(18,677)	(10,957)
Cash flows from investing activities:
Purchases of property and equipment	(5)	(2,485)
Proceeds from sale of property and equipment	0	19
Net cash used in investing activities	(5)	(2,466)
Cash flows from financing activities:
Proceeds from borrowings under loan and security agreement, net	5,500	0
Payments on borrowings under loan and security agreement, net	(5,200)
Proceeds from exercise of common stock options	106	69
Proceeds from issuance of convertible debt	0	30,000
Net cash provided by financing activities	406	30,069
Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	(18,276)	16,646
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	49,540	32,894
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	31,264	49,540
Supplemental disclosure of non-cash operating, investing and financing activities:
Interest payments on venture debt	422	229
Right-of-use asset obtained in exchange for new operating lease liability	$ 0	$ 7,666

Nature of the Business

Nature of the Business	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	1. Nature of the Business Q32 Bio Inc. (the Q32 or Company) was formed on April 10, 2017 as Admirx, Inc. under the laws of the state of Delaware and is headquartered in Waltham, Massachusetts. On March 20, 2020, the Company changed its name to Q32 Bio Inc. The Company aims to bring safer, more efficacious therapeutics to patients suffering from a wide range of devastating autoimmune and inflammatory diseases, starting with those rooted in the complement system and interleukin-7 (IL-7) Since its inception, the Company’s operations have been focused on organizing and staffing, business planning, raising capital, establishing the Company’s intellectual property portfolio and performing research and development of its product candidates, programs and platform. The Company has primarily funded its operations with proceeds from the sale of convertible preferred stock, convertible notes, venture debt and its collaboration arrangement. Risks and Uncertainties The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including but not limited to, risks associated with completing preclinical studies and clinical trials, obtaining regulatory approvals for product candidates, development by competitors of new biopharmaceutical products, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Programs currently under development will require significant additional research and development efforts, including preclinical and clinical testing, and will need to obtain regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales. Merger with Homology On November 16, 2023, the Company entered into an Agreement and Plan of Merger and Reorganization (the Merger Agreement) with Homology and Kenobi Merger Sub, Inc., a wholly owned subsidiary of Homology (Merger Sub). The Merger was completed on March 25, 2024. Pursuant to the Merger Agreement, Merger Sub merged with and into the Company, with the Company continuing as the surviving company and as a wholly owned subsidiary of Homology (the Merger). Homology changed its name to Q32 Bio, Inc., and the Company which remains as a wholly-owned subsidiary of Q32, changed its name to Q32 Bio Operations, Inc. On March 26, 2024, the combined company’s common stock began trading on the Nasdaq Global Market under the ticker symbol “QTTB”. The business of the Company will continue as the business of the combined company. The Merger is intended to qualify for federal income tax purposes as a tax-free reorganization under the provisions of Section 368(a) of the Internal Revenue Code of 1986, as amended. In connection with the Merger Agreement, certain parties entered into a subscription agreement with the Company to purchase shares of the Company’s common stock for an aggregate purchase Pre-Closing On March 25, 2024 (the Closing Date), following approval by the stockholders of the Company and Homology, the Pre-Closing Financing closed immediately prior to the consummation of the Merger. Shares of the Company’s common stock issued pursuant to the Pre-Closing Financing were converted into the right to receive 1,682,045 shares of Homology common stock after taking into account the Reverse Stock Split. On March 25, 2024, in connection with, and prior to the completion of the Merger, Homology effected a one-for-eighteen Reverse Stock Split of its then outstanding common stock. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”) which was March 25, 2024, all issued and outstanding shares of the Company’s common stock (including common stock issued upon the conversion of all the Company’s Series A, Series A-1 and Series B preferred stock, conversion of Q32 convertible notes, but excluding the common stock issued in Pre-Closing Financing) converted into the right to receive 7,017,842 shares of Homology’s common stock calculated in accordance with the Exchange Ratio at the Effective Time. Lastly, each option to purchase the Company’s shares that was outstanding and unexercised immediately prior to the Effective Time was converted into an option to purchase shares of Homology based on the Exchange Ratio. Immediately following the merger, stockholders of the Company owned approximately 74.4% of the outstanding common stock of the combined company. The Merger will be accounted for as a reverse recapitalization in accordance with U.S. GAAP. For accounting purposes, the Company is the accounting acquirer and Homology is the acquired company based on the terms of the Merger agreement and other factors, including: (i) the Company’s shareholders own a majority of the voting rights in the combined company; (ii) the Company designated a majority (seven of nine) of the initial members of the board of directors of the combined company; (iii) the Company’s executive management team became the management of the combined company; (iv) the pre-combination assets of Homology were primarily cash and cash equivalents, short-term investments, and other non-operating assets (the in-process research and development assets potentially remaining as of the combination are de minimis value); and (v) the combined company was named Q32 Bio, Inc. and is headquartered in the Company’s office in Waltham, Massachusetts. Accordingly, the merger was treated as the equivalent of the Company’s issuing stock to acquire the net assets of Homology. As a result of the merger, the net assets of Homology will be recorded at their acquisition-date fair value in the financial statements of the combined company and the reported operating results prior to the merger will be those of the Company. At the Effective Time, each person who as of immediately prior to the Effective Time was a stockholder of record of Homology or had the right to receive Homology’s common stock will be entitled to receive a contractual contingent value right (CVR) issued by Homology subject to and in accordance with the terms and conditions of a Contingent Value Rights Agreement between Homology and the rights agent (the CVR Agreement), representing the contractual right to receive cash payments from the combined company upon the receipt of certain proceeds from a disposition of Homology’s pre-merger Liquidity and Going Concern In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s ability to Continue as a Going Concern (Subtopic 205-40) The Company has incurred recurring losses since its inception, including a net loss of $53.7 million for the year ended December 31, 2023. In addition, as of December 31, 2023, the Company had an accumulated deficit of $187.1 million. To date, the Company has funded its net losses principally through the sale of preferred stock, convertible notes, debt, and proceeds from a collaboration arrangement. The Company expects its operating losses and negative operating cash flows to continue into the foreseeable future. The Company expects that its cash and cash equivalents as of December 31, 2023 of $25.6 million, together with the proceeds from the issuance of additional shares of common stock in the Pre-Closing net million on the closing date will be sufficient to fund its operating expenditures and capital expenditure requirements necessary to advance its research efforts and clinical trials for at least one year from the date of issuance of these consolidated financial statements. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. The Company’s inability to raise capital as and when needed could have a negative impact on its financial condition and ability to pursue its business strategies. There can be no assurance that the current operating plan will be achieved or that additional funding will be available on terms acceptable to the Company, or at all.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Acc Basis of Presentation The consolidated financial statements have been prepared in conformity with acco unt Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its wholly-owned Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the valuation of common stock awards, the valuation of convertible notes, the accruals of research and development expenses, the identification of material rights and estimation of standalone selling price for the identified performance obligations in the collaboration agreement and the inputs and assumptions to the over-time recognition of revenue under the collaboration agreement. Estimates are periodically reviewed considering changes in circumstances, facts and historical experience. Actual results may differ from the Company’s estimates. Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer (CEO). The Company and the CEO view the Company’s operations and manage its business as one operating segment. All material long-lived assets of the Company reside in the United States. Foreign Currency Transactions The Company’s functional currency is the United States dollar. Foreign currency transaction gains and losses are recorded in the statement of operations and comprehensive loss. Concentrations of Credit Risk and Significant Suppliers Financial instruments that potentially expose the Company to credit risk primarily consist of cash, cash equivalents, restricted cash and restricted cash equivalents. The Company maintains its cash, cash equivalents, restricted cash and restricted cash equivalents balances with accredited financial institutions and, consequently, the Company does not believe it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The The Company is dependent on contract development and manufacturing organizations (CDMOs) to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients, other raw materials and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients, other raw materials and formulated drugs. The Company is also dependent on contract research organization (CROs) which provide services related to the research and development activities in its programs. Off-Balance As of December 31, 2023 and 2022, the Company had no off-balance-sheet Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: Level 1 – Level 2 – Level 3 – Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the respective assets. Major additions and betterments are capitalized; maintenance and repairs, which do not improve or extend the life of the respective assets, are charged to operations as incurred. Upon retirement or sale, the cost and related accumulated depreciation Estimated Useful Life (Years) Lab equipment 5 Furniture and fixtures 3 Computer equipment 3 Leasehold improvements Shorter of useful life or term of associated lease Leases The Company evaluates whether an arrangement is or contains a lease at contract inception. If a contract is or contains a lease, lease classification is determined at lease commencement, which represents the date at which the underlying asset is made available for use by the Company. The Company’s lease terms are generally measured at the respective lease’s noncancelable term and exclude any optional extension terms as the Company is not reasonably certain to exercise such options. The Company elected the short-term lease exemption and therefore does not recognize lease liabilities and right of use assets for lease arrangements with the original lease terms of twelve months or less. Lease liabilities represent the Company’s obligation to make lease payments under a lease arrangement. Lease liabilities are measured as the present value of fixed lease payments, discounted using an incremental borrowing rate, as interest rates implicit in the Company’s lease arrangements are generally not readily determinable. The Company elected the practical expedient to not separate lease and non-lease The incremental borrowing rate represents the interest rate at which the Company could borrow a fully collateralized amount equal to the lease payments, over a similar term, in a similar economic environment. The Company determines the incremental borrowing rate at lease commencement, generally using a synthetic credit rating based on the Company’s financial position and negative cash flows, factoring in adjustments for additional risks based on the Company’s economic condition, a survey of comparable companies with similar credit and financial profiles, as well as additional market risks, as may be applicable. Right-of-use Right-of-use right-of-use right-of-use Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash with maturities of three months or less at the date of purchase to be cash equivalents. The Company maintains its cash in bank deposits accounts that are FDIC insured up the $250,000. At times, the Company’s bank accounts may exceed the federal insurance limits. Cash equivalents are comprised of money market accounts invested in U.S. Treasury securities. Restricted cash and restricted cash equivalents are comprised of deposits held by financial institutions as collateral for the company’s venture debt and used to collateralize letters of credit related to the Company’s lease arrangements. The C beginning-of-period end-of-period Cash, cash equivalents, restricted cash and restricted cash equivalents consisted of the following (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 25,617 $ 43,893 Restricted cash and cash equivalents 5,647 5,647 Total cash, cash equivalents, restricted cash and restricted cash equivalents $ 31,264 $ 49,540 Impairment of Long-Lived Assets The Company continually monitors events and changes in circumstances that could indicate carrying amounts of long-lived assets may be impaired, and assesses their recoverability based upon estimated future undiscounted future cash flows expected to be generated by the long-lived assets. If the estimated aggregate undiscounted cash flows are less than the carrying amount of the long-lived assets, an impairment charge, calculated as the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets, is recorded. The estimated fair value of the long-lived assets is determined based on the estimated discounted cash flows expected to be generated from the long-lived assets. Convertible notes During 2022, the Company recognized a liability as a result of the issuance of convertible promissory notes (the Convertible Notes). The Company accounts for all Convertible Notes issued under the fair value option election of ASC 825, Financial Instruments Debt and Warrant Issuance Costs The carrying value of the Company’s venture debt was recorded net of issuance costs and discount relating to the issuance of warrants. The amounts are amortized over the term of the debt using the effective interest method and recognized as interest expense. Convertible Preferred Stock The Company records all convertible preferred stock upon issuance at its respective fair value or original issuance price less issuance costs, as stipulated by its terms. The Company classifies its convertible preferred stock outside of stockholders’ deficit as the redemption of such shares is outside the Company’s control in certain circumstances, including upon liquidation or sale, as holders of the convertible preferred shares could cause redemption of the shares in these situations. The Company does not adjust the carrying value of the convertible preferred stock to redemption value until the contingent events that could give rise to redemption are considered probable of occurring. Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer. Once a contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The identification of material rights requires judgments related to the determination of the value of the underlying good or service relative to the option exercise price. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company assesses whether each promised good or service is distinct for the purpose of identifying the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). In assessing whether a promised good or service is distinct, the Company considers factors such as the license terms, the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, an entity is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is determined and allocated to the identified performance obligations in proportion to their stand-alone selling prices (SSP) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The amount of variable consideration included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty related to the variable consideration is resolved. At the end of each subsequent reporting period, the Company re-evaluates catch-up adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time, and if over time recognition is based on the use of an output or input method. Collaboration Arrangement The Company analyzes first its collaboration arrangement to assess whether it is within the scope of FASB ASC Topic 808, Collaborative Arrangements (ASC 808) to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company and its collaboration partner are within the scope of other accounting literature, including ASC 606. If it is concluded that some or all aspects of the arrangement represent a transaction with a customer, the Company will account for those aspects of the arrangement within the scope of ASC 606. ASC 808 provides guidance for the presentation and disclosure of transactions in collaborative arrangements, but it does not provide recognition or measurement guidance. Therefore, if the Company concludes a counterparty to a transaction is not a customer or otherwise not within the scope of ASC 606, the Company considers the guidance in other accounting literature, including the guidance in ASC 606, as applicable or by analogy to account for such transaction. The classification of transactions under the Company’s arrangements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants. Research and Development Expenses Research and development costs are expensed as incurred. Research and Development expenses are comprised of costs incurred in performing research and development activities, including salaries, stock-based compensation and benefits, costs for clinical research organizations and other outsourced activities; laboratory supplies; technology licenses, software and other information technology support; facilities and depreciation. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development expenses in the period in which they are incurred. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed. The Company has entered into various research and development related contracts with external parties. The payments under these agreements are recorded as research and development expenses as the underlying services are performed or the goods are received. The Company records accrued liabilities for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued and prepaid balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. Research and Development Tax Incentive The Company is eligible under the AusIndustry Research and Tax Development Tax Incentive Program to obtain a cash amount from the Australian Taxation Office (ATO). The tax incentive is available to the Company on the basis of specific criteria with which the Company must comply related to research and development expenditures in Australia. The Company adopted on January 1, 2022, ASU No. 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance 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 statement of operations. Stock-Based Compensation The Company accounts for stock-based awards in accordance with ASC Topic 718, Compensation – Stock Compensation The Company’s equity incentive plan allows for the issuance of restricted stock awards to employees and non-employee Determination of Fair Value of Common Stock on Grant Dates The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model, which requires inputs based on certain subjective assumptions, including the fair value of the Company’s common stock, expected stock price volatility, the expected term of the award, the risk-free interest rate, and expected dividends (see Note 11). The Company has been a private company and lacks company-specific historical and implied volatility information for its stock. Therefore, it estimates its expected stock price volatility based on the historical volatility of publicly traded peer companies. The expected term of options was calculated using the simplified method, which represents the average of the contractual term of the option and the weighted-average vesting period of the option. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate expected term. The expected term of options granted to non-employees Due to the absence of an active market for the Company’s common stock, the Company and the board of directors were required to determine the fair value of the Company’s common stock at the time of each grant of a stock-based award. The Company estimated the fair value of its common stock utilizing methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation The Company classifies stock-based compensation expense in its statements of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. Income Taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. Should the actual amounts differ from these estimates, the amount of the Company’s valuation allowance could be materially impacted. Changes in these estimates may result in significant increases or decreases to the tax provision in a period in which such estimates are changed, which in turn would affect net income or loss. Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step more-likely-than-not Comprehensive Income (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. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying financial statements. Net Loss per Share Attributable to Common Stockholders Net loss per share attributable to common stockholders is determined using the two-class Diluted net loss per share is computed using the more dilutive of (a) the two-class if-converted average number of common shares included in the computation of diluted net loss gives effect to all potentially dilutive common equivalent shares, including outstanding stock options and preferred stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Deferred Transaction Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process paid-in in-process Subsequent Event Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated events occurring after the date of its consolidated balance sheet through March 26, 2024, the date of these consolidated financial statements were available to be issued. See Note 17. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that are 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 financial position or results of operations upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) – Measurement of Credit Losses on Financial Instruments, In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity’s Own Equity (Subtopic 815-40) Recently Issued Accounting Standards Not Yet Adopted In November 2023, the FASB issued Accounting Standards Update 2023-07, Segment Reporting (Topic 280: Improvements to Reportable Segment Disclosures (“ASU 2023-07”)) On December 14, 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740)—Improvements to Income Tax Disclosures No. 2023-09 2023-09

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The carrying values of the Company’s prepaid expenses and other current assets, accounts payable, and accrued expenses and other current liabilities approximate their fair value due to their short-term nature. The carrying value of the Company’s term loan as of December 31, 2023 (see Note 8) approximated fair value based on interest rates currently available to the Company. The tables below presents information about the Company’s assets and liabilities that are regularly measured and carried at fair value on a recurring basis at December 31, 2023 and 2022 and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value, which is described further within Note 2, Summary of Significant Accounting Policies. Financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2023 are summarized as follows (in thousands): Description Balance as of December 31, 2023 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Assets Cash equivalents: Money market funds $ 24,100 $ 24,100 $ —  $ —  Restricted cash equivalents: Money market funds 5,000 5,000 —  —  Total $ 29,100 $ 29,100 $ —  $ —  Liabilities Convertible Notes $ 38,595 $ —  $ —  $ 38,595 Total $ 38,595 $ —  $ —  $ 38,595 Financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 are summarized as follows (in thousands): Description Balance as of December 31, 2022 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Assets Cash equivalents: Money market funds $ 42,496 $ 42,496 $ —  $ —  Restricted cash equivalents: Money market funds 5,000 5,000 —  —  Total $ 47,496 $ 47,496 $ —  $ —  Liabilities Convertible Notes $ 32,402 $ —  $ —  $ 32,402 Total $ 32,402 $ —  $ —  $ 32,402 Money market funds were valued by the Company using quoted prices in active markets for identical securities, which represent a Level 1 measurement within the fair value hierarchy. During the years ended December 31, 2023 and 2022, there were no transfers between Level 1, Level 2 and Level 3. There have been no impairments of the Company’s assets measured and carried at fair value during the years ended December 31, 2023 and 2022. The Company issued convertible notes (Convertible Notes) totaling $30,000,000 during the year ended December 31, 2022. The Company concluded that the Convertible Notes and its related features are within the scope of ASC 825, Financial Instruments Year ending December 31, 2023 Scenario 1 Scenario 2 Scenario 3 Probability of each scenario 80.0 % 15.0 % 5.0 % Expected Term (years) 0.25 0.25 0.42 Required market rates of return 15.0 % 15.0 % 15.0 % The Convertible Notes had an estimated fair value of $38.6 million as of December 31, 2023. The Company recorded in other income (expense), net, an interest expense of $1.5 million and a charge of $4.7 million on the change in estimated fair value during the year ended December 31, 2023. There was no change in fair value attributable to the instrument-specific credit risk for the year ended December 31, 2023.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net Property and equipment, net consisted of the following as of (in thousands): December 31, 2023 2022 Lab equipment $ 1,382 $ 1,382 Furniture and fixtures 341 341 Computer equipment 85 85 Leasehold improvements 940 935 Total property and equipment 2,748 2,743 Less accumulated depreciation (966 ) (467 ) Property and equipment, net $ 1,782 $ 2,276 Depreciation expense for the years ended December 31, 202 3 2

Prepaid Expenses, Other Current

Prepaid Expenses, Other Current Assets and Other Noncurrent Assets	12 Months Ended
	Dec. 31, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid Expenses, Other Current Assets and Other Noncurrent Assets	5. Prepaid Expenses, Other Current Assets and Other Noncurrent Assets Prepaid expenses and other current assets consisted of the following as of (in thousands): December 31, 2023 2022 Payroll tax credit $ 755 $ 948 Prepaid external research and development 1,834 1,329 Research credit receivable —  116 Prepaid expenses 427 421 Other 83 146 Total prepaid expenses and other current assets $ 3,099 $ 2,960 Other noncurrent assets consisted of the following as of (in thousands): December 31, 2023 2022 Deferred transaction costs $ 3,912 $ — Prepaid external research and development—long term 676 — Other 23 108 Total other noncurrent assets $ 4,611 $ 108

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following as of (in thousands): December 31, 2023 2022 Accrued external research and development $ 3,578 $ 4,077 Accrued compensation and related expenses 3,003 2,791 Accrued taxes payable 316 570 Operating lease liability 538 471 Accrued professional services and other 2,328 1,588 Total accrued expenses and other current liabilities $ 9,763 $ 9,497

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies As of December 31, 2023, the Company has several ongoing clinical studies in various clinical trial stages. Its most significant contracts relate to agreements with clinical research organizations (CROs) for clinical trials and preclinical studies and contract development and manufacturing organizations (CMOs), which the Company enters into in the normal course of business. The contracts with CROs and CMOs are generally cancellable, with notice, at the Company’s option. Operating lease In 2021 the Company entered into a long-term operating lease agreement for its current corporate headquarters in Waltham, Massachusetts. The lease for the Company’s corporate headquarters provides approximately 15,000 rentable square feet for general office use and research lab facilities. The lease commencement date began on January 1, 2022 and the Company did not take control or have the right to use the leased property until this time. The lease term ends in December 2031. The Company has an option to extend the lease term for an additional five years. The initial rent for the office space is approximately $970 thousand per year, increasing every year by 3% for total aggregate payment of $11.1 million. Upon the commencement date, the Company established a right-of-use right-of-use As of December 31, 2023, the Company’s operating lease had a weighted-average remaining lease term of eight years and weighted average incremental borrowing rate of 7.5%. Amounts reported in the consolidated balance sheet for leases where the Company is the lessee as of December 31, 2023 and 2022 were as follows (in thousands): December 31, 2023 2022 Assets: Operating lease right-of-use $ 6,301 $ 6,890 Total operating lease right-of-use $ 6,301 $ 6,890 Liabilities: Current: Operating lease liabilities $ 538 $ 471 Noncurrent: Operating lease liabilities, net of current portion 6,248 6,786 Total operating lease liabilities $ 6,786 $ 7,257 The following table summarizes operating lease costs for the years ended December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Fixed lease costs $ 999 $ 1,232 Variable lease costs 73 103 Total lease costs $ 1,072 $ 1,335 Variable lease costs were primarily related to operating expenses, taxes and insurances associated with the operating leases, which were assessed based on the Company’s proportionate share of such costs for the leased premises. As these costs are generally variable in nature, they were not included in the measurement of the operating lease right-of-use non-cancelable Minimum Rental Payments 2024 $ 1,029 2025 1,060 2026 1,092 2027 1,124 2028 1,158 Thereafter 3,687 Total minimum lease payments 9,150 Less imputed interest (2,364 ) Total lease liability $ 6,786 Lease liability, current portion $ 538 Lease liability, net of current portion 6,248 Total $ 6,786 License Agreements License Agreement with the University of Colorado In August 2017, the Company entered into an exclusive license agreement, as amended in February 2018, September 2018, and April 2019 (the Colorado License Agreement), with The Regents of the University of Colorado (Colorado), pursuant to which the Company obtained worldwide, royalty-bearing, sublicensable licenses under certain patents and know-how ADX-097. know-how non-exclusive know-how. ADX-097, In addition, the Company agreed to pay Colorado (i) development and sales milestone payments in an aggregate amount of up to $2.2 million per licensed product for the first three products, (ii) tiered royalty rates on cumulative net sales of licensed products in the low single digit percentages, (iii) 15% of sublicense income and (iv) ongoing fees associated with the prosecution, maintenance, or filing of the licensed patents. The Company’s obligation to pay royalties to Colorado commences, on a licensed product-by-licensed country-by-country Unless earlier terminated by either party pursuant to its terms, the Colorado License Agreement will expire upon the expiration of the Royalty Term in all countries. The Company may terminate the Colorado License Agreement for convenience upon providing prior written notice to Colorado. Colorado may terminate the Colorado License Agreement or convert the Company’s exclusive license to a non-exclusive During the years ended December 31, 2023 and 2022, the Company recorded research and development expense of zero and $50 thousand, respectively for milestone related to the Colorado License Agreement. The financial statements as of December 31, 2023 and 2022 do not include liabilities with respect to royalty fees on the license agreement as the Company has not yet generated revenue and the achievement of certain milestones is not yet probable. License Agreement with Bristol-Myers Squibb Company In September 2019, the Company entered into a license agreement, as amended in August 2021 and July 2022 (the BMS License Agreement), with Bristol-Myers Squibb Company (BMS), pursuant to which the Company obtained sublicensable licenses from BMS to research, develop and commercialize licensed products, including bempikibart, for any and all uses worldwide. The licenses granted to the Company are exclusive with respect to BMS’s patent rights and know-how non-exclusive know-how know-how In consideration for the license, the Company made an upfront payment to BMS of $8 million, issued 6,628,788 Series A preferred shares to BMS and agreed to use commercially reasonable efforts to develop and commercialize at least one licensed product in key geographic markets. In addition, the Company agreed to pay BMS (i) development and regulatory milestone payments in aggregate amounts ranging from $32 million to $49 million per indication for the first three indications and commercial milestone payments in an aggregate amount of up to $215 million on net sales of licensed products, (ii) tiered royalties ranging from rates in the mid-single The Company’s obligation to pay BMS royalties under subsection (ii) above commences, on a licensed product-by-licensed country-by-country years from the first commercial sale of such licensed product in such country, (y) the last to expire licensed patent right covering bempikibart or such licensed product in such country, and (z) the expiration or regulatory or marketing exclusivity for such licensed product in such country (Royalty Term). If the Company undergoes a change of control prior to certain specified phase of development, the development and milestone payments are subject to increase by a low double digit percentage and the royalty rates are subject to increase by a low sub single digit percentage. Unless terminated earlier by either party pursuant to its terms, the BMS License Agreement will expire on a country-by-country product-by-licensed During the year ended December 31, 2019, the Company recorded in-process-research As of December 31, 2023, no events have occurred that would require payment of the milestones, royalties or sublicense fees. Legal Proceedings The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of FASB ASC Topic 450, Contingencies Indemnification Arrangements As permitted under Delaware law, the Company has agreements whereby it indemnifies certain of its investors, stockholders, employees, officers, and directors (collectively, the Indemnified Parties) for certain events or occurrences while the Indemnified Parties are, or were serving, at its request in such capacity. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited; however, the Company has an Executive Liability insurance policy that limits its exposure and enables it to recover a portion of any future amounts paid up to $5.0 million. The Company believes the estimated fair value of these indemnification agreements is minimal. The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to these agreements, the Company indemnifies, holds harmless, and agrees to reimburse the Indemnified Parties for losses suffered or incurred by the Indemnified Parties, generally the Company’s business partners or customers, in connection with any U.S. patent or any copyright or other intellectual property infringement claim by any third party with respect to the Company’s products. 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.

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	8. Debt Venture Debt On December 11, 2020, the Company entered into a Loan and Security Agreement with Silicon Valley Bank, a California corporation (Loan Agreement) for a lending facility of up to $25 million. The Company received $5.0 million upon execution of the Agreement (2020 Term A Loan Advance) and had the ability to draw up to $20.0 million in three separate term loan advances if certain performance milestones are met. The term loan bears interest at an annual rate equal to the greater of the prime rate or 3.25%. The Loan Agreement provides for interest-only payments until April 30, 2022, and repayment of the aggregate outstanding principal balance of the term loan in monthly installments starting on July 1, 2022 through December 1, 2023. The commencement of principal payments and the maturity date will be deferred by one year upon the occurrence of a contingent event. In addition, the Company paid a fee of $91 thousand upon closing and is required to pay a fee of 2.0% of the aggregate amount of advances under the Loan Agreement at maturity. At its option, the Company may elect to prepay all or a portion of the outstanding advances by paying the principal balance, and all accrued and unpaid interest, and a prepayment premium. In connection with the Loan Agreement, the Company granted the lender a security interest in all of its personal property now owned or hereafter acquired, excluding intellectual property (but including the rights to payment and proceeds from the sale, licensing or disposition of intellectual property), and a negative pledge on intellectual property. The Loan Agreement also contains certain events of default, representations, warranties and non-financial On June 30, 2022, a second amendment to the Loan Agreement was entered into with the lender that extended the interest-only payment until December 31, 2022 followed by 24 equal monthly payments of principal plus interest. The loan matures on December 31, 2024. The amendment increases the final payment from 2.0% to 4.0% of the advanced payment and modifies the prepayment premium. On August 10, 2022, a third amendment to the Loan Agreement was entered into with the lender. Per the terms of the amendment and in conjunction with the Collaboration Agreement (as defined below), the Company transferred $5.0 million into a restricted cash collateral money market account which is included as Restricted cash and restricted cash equivalents on the balance sheet. This restricted cash equivalent covers the amount of the debt outstanding as of the third amendment effective date. On December 21, 2022, a fourth amendment to the Loan Agreement was entered into with the lender that extended the interest-only payment until July 1, 2023 followed by 18 equal monthly payments of principal plus interest. The loan matures on December 1, 2024. On April 26, 2023, a fifth amendment to the Loan Agreement was entered into with the lender. The amendment provides that the Company must maintain at least 50% of its consolidated cash with the lender. In addition, the Company shall at all times have on deposit in operating and depository accounts maintained with the lender, unrestricted and unencumbered cash in an amount equal to the lesser of (i) 100% of the dollar value of the Company’s consolidated cash and (ii) 110% of the then-outstanding obligations of the Company to the bank. So long as, the Company is in compliance with those terms, the Company shall be permitted to maintain accounts with other banks or financial institutions. On July 12, 2023, a sixth amendment to the Loan Agreement was entered into with the lender. The amendment provides for one term loan advance (the 2023 Term A loan advance) in an original principal amount of $5.5 million and required the Company to repay the outstanding 2020 Term A Loan Advance of $5.0 million, including the final payment of $0.2 million. Upon the occurrence of a contingent event, the lender shall make up to three additional term loan advances at the Company’s request in original principal amounts of $7.0 million, $7.5 million and $5.0 million. The amounts must be drawn by the Company before March 31, 2024, March 31, 2025 and July 1, 2025, respectively. The interest-only period extends through June 30, 2024 followed by 36 equal monthly payments of principal plus interest. The term loan bears interest at an annual rate equal to the greater of the prime rate minus 0.25% or 8.00%. Pursuant to this amendment, specifically the interest-only period through June 30, 2024, the Company classified the principal of its venture debt as noncurrent on the consolidated balance sheet as of December 31, 2022. On November 2, 2023, a seventh amendment to the Loan Agreement was entered into with the lender. The additional loan advance of $7.0 million, the first advance stated in the sixth amendment to the Loan Agreement, could be drawn down once the company received net cash proceeds of at least $75.0 million from (a) the issuance and sale of its equity securities to investors satisfactory to the lender and/or (b) a business development transaction satisfactory to the lender; provided that, at least, $37.5 million of such net cash proceeds must be received from the issuance and sale of equity securities to investors satisfactory to the lender. The seventh amendment extends the time the Company has to receive the net proceeds to March 31, 2024. In conjunction with the Loan Agreement, the Company issued warrants to purchase 166,371 shares of common stock to the lender at a per share price of $0.33 with a maximum contractual term of 10 years. The warrants had a total relative fair value of $39 thousand upon issuance and were recorded as a debt discount. In conjunction with the sixth amendment, the Company issued warrants to purchase 211,528 shares of common stock to the lender at a per share price of $0.36 with a maximum contractual term of 10 years. The warrants are issued in two separate tranches of 105,764 based upon certain milestone events. The warrants had a de minimis total relative fair value at the time of issuance. Pursuant to ASC Topic 480, Distinguishing Liabilities from Equity Derivatives and Hedging Interest expense was $531 thousand and $327 thousand for the years ended December 31, 2023 and 2022, respectively. The effective rate on the Loan Agreement, including the amortization of the debt discount and issuance costs was 10.42% and 9.49% at December 31, 2023 and 2022, respectively. The components of the long-term debt balance are as follows (in thousands): December 31, 2023 2022 Principal amount of term loans $ 5,500 $ 5,000 Unamortized debt discount and issuance costs (41 ) 72 Carrying amount 5,459 5,072 Less current portion (878 ) —  Long-term debt, net $ 4,581 $ 5,072 Convertible Notes On May 20, 2022, the Company entered into an agreement with the existing investors of the Company to purchase up to an aggregate of $30.0 million in convertible notes (the Convertible Notes). The Convertible Notes bear interest at 5.0% per annum. The Convertible Notes become due on demand of the Convertible Noteholders one year from the date of issuance. On April 27, 2023, the Company amended the maturity dates for the Convertible Notes. On May 20, August 5 and December 23, 2022, the Company received $8.3 million, $5.0 million, and $16.7 million, respectively, in exchange for issuance of the Convertible Notes. Interest expense was $1.5 million and $376 thousand for the year ended December 31, 2023 and 2022, respectively. The Convertible Notes contain mandatory conversion features whereby the total outstanding amount of principal and accrued and unpaid interest of the Convertible Notes shall automatically convert into shares of common stock upon certain qualified financings. The total outstanding amount of principal and accrued and unpaid interest of the Convertible Notes convert into common shares at 90% of the purchase price of the mandatory conversion events. If the mandatory conversion events do not occur the holders of the Convertible Notes may request the Convertible Notes plus accrued interest be converted into Series B preferred stock at the Series B convertible price of $1.0971. The Company has elected to account for the Convertible Notes at fair value where changes in fair value of the notes are measured through the consolidated statements of operations and comprehensive loss until settlement. As the Convertible Notes are due on demand. the Company recorded the Convertible Notes at fair value totaling $32.4 million within current liabilities on its consolidated balance sheet as of December 31, 2022. Subsequent to December 31, 2023 and per the Merger further discussed in Note 1, the Convertibles Notes converted into 29,853,711 shares of common stock. As the Convertible Notes were settled with equity securities subsequent to the balance sheet date but prior to the issuance of the financial statements, per ASC 470 Debt million as a long-term liability on its consolidated balance sheet as of December 31, 2023. The Company

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2023
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	9. Convertible Preferred Stock In July 2018, the Company entered into a Series A and A-1 p s In connection with the initial issuance of the Series A preferred stock, the holders received the right to purchase, and the Company the obligation to sell, an additional 31,000,000 shares of Series A preferred stock at the same purchase price as the initial closing upon achieving certain milestones. The specified milestones could be waived upon written consent of the holders of a majority of the shares of Series A preferred stock. The Company determined that the tranche rights did not meet the definition of a freestanding financial instrument because they are not legally detachable. Further, the Company determined that the tranche rights do not meet the definition of an embedded derivative that require bifurcation from the equity instrument. In August 2019, the Company issued 3,000,000 shares of Series A preferred stock at a price of $1.00 per share less issuance costs of $30 thousand for net proceeds of $2.97 million upon the achievement of specified milestones. In September 2019, the Company issued 28,000,000 shares of Series A preferred stock at a price of $1.00 per share less issuance costs of $40 thousand for net proceeds of $27.96 million upon the receipt of a waiver of the final milestones being met. In September 2019, the Company issued 6,628,788 Series A preferred shares in association with the purchase of a license agreement with BMS as further described in Note 7. On August 31, 2020, the Company entered into a Series B Preferred Stock Purchase Agreement and issued 34,636,767 shares of Series B p s In connection with the initial issuance of the Series B preferred stock, the holders received the right to purchase, and the Company the obligation to sell, an additional 17,318,383 shares of Series B preferred stock at the same purchase price as the initial closing upon achieving certain milestones. The specified milestones could be waived upon written consent of the holders of a majority of the shares of Series B preferred stock. The Company also had the right to issue additional shares of Series B p s On October 15, 2020, the Company issued an additional 1,822,987 shares of Series B p s In November and December of 2021, the Company issued 18,229,873 shares of Series B p The Series A p A-1 Voting Rights The holders of the Preferred Stock are entitled to vote, together with the holders of common stock, on all matters submitted to stockholders for a vote. Each holder of outstanding shares of Preferred Stock shall be entitled to cast the number of votes equal to the number of shares of common stock into which the shares of Preferred Stock held by such holder are convertible at the time of such vote. Except as provided by law or by the other provisions of the Company’s Second Amended and Restated Certificate of Incorporation, holders of Preferred Stock vote together with the holders of common stock as a single class and on an as-converted to Common Stock basis. The holders of record of the shares of Series B p s p s Conversion Each share of Preferred Stock is convertible, at the option of the holder, at any time, and without the payment of additional consideration, into such number of fully paid and non-assessable The Applicable Preferred Stock Original Issue Price is $1.00 per Series A share, $0.885 per Series A1 share and $1.0971 per Series B share, subject to appropriate adjustment in the event of any stock dividend, stock split, combination, or other similar recapitalization with respect to the Preferred Stock. The Applicable Preferred Stock Conversion Price is initially $1.00 for Series A, $0.885 for Series A1 and $1.0971 for Series B, subject to appropriate adjustment in the event of any stock dividend, stock split, combination, or other similar recapitalization and other adjustments, as set forth in the Company’s Second Amended and Restated Certificate of Incorporation. Each share of Preferred Stock will automatically convert into shares of common stock at the then effective conversion ratio (i) upon an initial public offering of the Company’s common stock, provided that such offering results in at least $50 million of gross proceeds, after deducting the underwriting discount and commissions, to the Company or (ii) upon the vote or written consent of the holders of a majority of the outstanding shares of Preferred Stock. On March 25, 2024, immediately prior to completing the Merger, all classes of convertible Preferred Stock of Q32 were converted to Q32 common stock. The Series A convertible preferred stock converted to 47,628,788 shares of Q32 common stock, the Series A-1 convertible preferred stock converted to 6,500,000 shares of Q32 common stock and the Series B convertible preferred stock converted to 54,689,627 shares of Q32 common stock. The conversion of the Q32 preferred stock into shares of Q32 common stock results in an increase of $11 thousand to Common stock and an increase of $111.4 million to additional paid-in-capital immediately prior to completing the Merger. Dividends The Company may not declare, pay or set aside any dividends on any other class or series of stock of the Company, other than dividends on common stock payable in common stock, unless the holders of the Preferred Stock first receive, or simultaneously receive, a dividend on each outstanding Preferred Stock of an amount equal to six percent (6%) of the applicable preferred stock original issue price (as defined below) per share of such series of Preferred Stock (subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to such series of Preferred Stock). Dividends are non-cumulative. Liquidation Preference In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or Deemed Liquidation Event (as defined below), the holders of shares of Preferred Stock then outstanding shall be entitled, on a pari passu basis, to be paid out of the assets of the Company available for distribution to its stockholders before any payment will be made to the holders of common stock by reason of their ownership thereof, an amount per share equal to with respect to the Series A, A1 and B preferred stock, one times the original issue price, plus any dividends declared but unpaid. If upon any such liquidation, dissolution or winding up of the Company or Deemed Liquidation Event, the assets of the Company available for distribution to its stockholders shall be insufficient to pay the holders of shares of Preferred Stock the full amount to which they shall be entitled, the holders of the shares of Preferred Stock shall share ratably in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the shares held by them upon such distribution if all amounts payable on or with respect to such shares were paid in full. After the payment of all preferential amounts required to be paid to the holders of shares of Preferred Stock, the remaining assets of the Company available for distribution to its stockholders will be distributed among the holders of the shares of Series A, A1 and B preferred stock, and common stock, pro rata based on the number of shares held by each such holder, treating for the purpose all such securities as if they had been converted to common stock. Unless the holders of a majority of the Preferred Stock, voting together as a single class, elect otherwise, a Deemed Liquidation Event shall include (i) a merger or consolidation (other than one in which stockholders of the Company own a majority by voting power of the outstanding shares of the surviving or acquiring corporation) or (ii) a sale, lease, transfer, exclusive license, or other disposition of substantially all of the assets of the Company. Redemption The Preferred Stock is not redeemable at the option of the holders thereof. However, the Preferred Stock is redeemable upon the occurrence of certain contingent events, unless otherwise determined by the holders. As it relates to the payment upon the occurrence of a contingent event, the Company evaluated the Preferred Stock in accordance with the guidance in FASB ASC Topic 480, Distinguishing Liabilities from Equity

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2023
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common Stock	10. Common Stock As of December 31, 2023 the Company’s Second Amended and Restated Certificate of Incorporation authorized the Company to issue 225,000,000 shares of common stock, $0.0001 par value per share, respectively. 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 preferences of the holders of the Preferred Stock set forth above. Each share of common stock entitles the holder to one vote, together with the holders of the Preferred Stock, on all matters submitted to the stockholders for a vote. On May 20, 2022, December 8, 2022 and November 16, 2023, the Company amended and restated the Certificate of Incorporation to increase the authorized common stock by 5,000,000, 6,900,000 and 83,100,000 respectively to 225,000,000. Common stockholders are entitled to receive dividends, as may be declared by the Company’s board of directors, if any, subject to the preferential dividend rights of the Preferred Stock. No dividends have been declared or paid during the years ended December 31, 2023 and 2022. The Company has reserved the following shares of common stock for future issuance: As of December 31, 2023 2022 Shares reserved upon the conversion of authorized Series A preferred 47,628,788 47,628,788 Shares reserved upon the conversion of authorized Series A1 preferred 6,500,000 6,500,000 Shares reserved upon the conversion of authorized Series B preferred 54,689,627 54,689,627 Shares reserved for future issuance under the 2017 Stock Incentive Plan 1,167,685 1,669,058 Shares reserved upon the conversion of the convertible notes 29,853,711 —  Shares reserved for stock option exercises 23,165,393 22,997,639 Shares reserved for warrants 377,899 166,371 163,383,103 133,651,483

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation Grants under the 2017 Plan The Company adopted the 2017 Stock Option and Grant Plan and subsequent amendments (the Plan) with 25,956,535 shares of common stock reserved for issuance to employees, directors, and consultants. The Plan allows for the grant of incentive stock options, non-statutory Since inception, the Company has granted restricted stock awards, non-qualified Restricted Stock For the restricted stock awards, the purchase price equaled the estimated fair value of the common stock as determined by the board of directors on the date of grant. The Company has the right, but not the obligation to repurchase unvested shares at the original purchase price if employees or non-employees two-year . The aggregate fair value of restricted stock awards that vested during the year ended December 31, 2023 was zero. No restricted stock awards were issued during the years ended December 31, 2023 and 2022. As of December 31, 2023, no shares remained subject to a repurchase right by the Company. As of December 31, 2023, there was unrecognized compensation cost related to the unvested restricted stock awards. Stock Options Stock options granted by the Company typically vest over a four-year period and have a ten-year Number of Weighted- Weighted- Aggregate Outstanding at December 31, 2022 22,997,639 $ 0.34 7.94 $ 362 Granted 3,221,672 0.52 —  Exercised (333,619 ) 0.32 —  Cancelled (2,720,299 ) 0.35 —  Outstanding at December 31, 2023 23,165,393 $ 0.36 6.87 $ 10,712 Exercisable at December 31, 2023 12,899,524 $ 0.33 5.36 $ 6,299 The weighted-average grant date fair value per share of options granted in the period ended December 31, 2023 was $0.40. The total fair value of options vested during 2023 was $1.4 million. As of December 31, 2023, total unrecognized compensation costs to the unvested stock options were approximately $3.0 million, which is expected to be recognized over a weighted-average period of 2.5 years. The total intrinsic value of options exercised during the ye a Stock-Based Compensation Expense For purposes of calculating stock-based compensation, the Company estimates the fair value of stock options using the Black-Scholes option-pricing model. This model incorporates various assumptions, including the expected volatility, expected term, and interest rates. The underlying assumptions used to value stock options granted using the Black-Scholes option-pricing model during the years ended December 31, 2023 and 2022 were as follows: Year Ended December 31, 2023 2022 Risk-free interest rate range 3.59% – 4.67% 1.74% – 3.90% Expected dividend rate —  —  Expected term (years) range 5.08 – 6.12 5.94 – 6.11 Expected stock price volatility range 88.9% – 94.0% 85.9% – 88.9% Risk-Free Interest Rate – Expected Dividend – Expected Term – Expected Volatility – Fair Value of Common Stock Stock-Based Compensation Expense The Company recorded stock-based compensation expense in the following expense categories of its statements of operations (in thousands): Year Ended December 31,   2023     2022   Research and development $ 500 $ 447 General and administrative 929 791 Total stock-based compensation expense $ 1,429 $ 1,238

Agreements with Horizon

Agreements with Horizon	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Agreements with Horizon	12. Agreements with Horizon The Company entered into a Collaboration and Option Agreement (the Horizon Collaboration Agreement) and an Asset Purchase Agreement (the Purchase Agreement, collectively with the Horizon Collaboration Agreement, the Horizon Agreements) with Horizon Therapeutics Ireland DAC (Horizon) on August 12, 2022. Prior to the execution of the Horizon Agreements, the Company had completed a Phase 1 study for bempikibart (formerlyADX-914, anti-inerleukin-7 non-tangible Per the terms of the Horizon Collaboration Agreement, the Company received a total of $55.0 million for initiation of certain development activities associated with the planned clinical trials and related activities. If Horizon had exercised its option, the Company would have received a prespecified fee pursuant to the Purchase Agreement. The Company would also have been entitled to receive additional payment from Horizon based on the achievement of future development and regulatory milestones as well as royalty payments on annual net sales. Horizon Termination Agreement In October 2023, Amgen Inc. (Amgen) completed its acquisition of Horizon Therapeutics public limited company (Horizon plc). Following the closing of Amgen’s acquisition of Horizon plc, the Company agreed with Amgen to mutually terminate the Horizon Agreements and in November 2023, the Company and Horizon entered into a termination agreement (the Horizon Termination Agreement), pursuant to which Horizon’s option to acquire the bempikibart program was terminated. As a result, the Company retained all initial consideration and development funding received under the Horizon Collaboration Agreement and regained full development and commercial rights to bempikibart. In consideration for the Horizon Termination Agreement, the Company agreed to pay Horizon regulatory and sales milestones payments of up to an aggregate amount of $75.1 million upon the first achievement of certain regulatory and sales milestones with respect to bempikibart. Accounting Analysis Prior to the termination agreement, the Company concluded the arrangement was within the scope of Topic 606. Specifically, the Company concluded that the research services required to be performed as part of the Horizon Collaboration Arrangement represented an output of the Company’s ordinary activities, and this represents a contract with a customer. At the commencement of the collaboration arrangement with Horizon, the Company identified two performance obligations related to the development activities of bempikibart, one of each of the specified clinical trials, with each composing the services related to the clinical trial and other related development activities. The Company also identified a material right related to the option for Horizon to purchase bempikibart. The material right was considered a separate performance obligation pursuant to the provisions of Topic 606. The Company determined the transaction price The following table summarizes the allocation of the transaction price allocated to each performance obligation (in thousands): Transaction AD phase 2 research services $ 25,417 AA phase 2 research services 18,265 Material right for the purchase of ADX-914 11,318 Total $ 55,000 The Company concluded that the consideration allocated to the research service performance obligations should be recognized over time as Horizon received the benefit of the research activities as the activities were performed. The Company has determined that this method was most appropriate as progress towards completion of research is largely driven by time and effort spent and costs incurred to perform this research. As of December 31, 2022, the Company had received $32.5 million of the $55.0 million transaction price from Horizon. The Company recognized $6.7 million of collaboration agreement revenue for the year ended December 31, 2022. As of December 31, 2023, the Company had received the full $55.0 million, which the Company retains. The Termination Agreement is accounted for as a modification because it does not result in the addition of distinct goods or services. Since the two performance obligations and the material right are terminated with no further performance obligations aside from the contingent payments to Horizon of up to $75.1 million, the Company recognized the remaining deferred revenue in the fourth quarter of 2023. Upon the execution of the Horizon Termination Agreement, the Company became obligated to pay Horizon up million contingent on regulatory and sales-based milestones or up to million in excess of the cash received. These potential payments to the customer are not in exchange for a distinct good or service; therefore, the Company accounts for consideration payable to a customer as a reduction of the transaction price under ASC 606. The Company concluded that the million of arrangement consideration previously recognized should be fully constrained as a result of the contingent consideration payable to the customer, and accordingly, all amounts previously recognized as revenue were reversed in the fourth quarter of 2023 and a refund liability was established for the $55.0 million cash received during the term of the collaboration agreement. No amounts have been recognized related to the remaining potential payment to Horizon (up to $ 20.1

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	13. Related Party Transactions The Company has consulting and advisory agreements with certain investors and board members which are considered to be related party transactions. For the years ended December 31, 2023 and 2022, the Company recorded expense of zero and $87 thousand, respectively, related to services provided by these investors. No amounts were due to related parties at December 31, 2023 or 2022.

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2023
Defined Contribution Plan [Abstract]
Defined Contribution Plan	14. Defined Contribution Plan The Company has a defined contribution savings plan under Section 401(k) of the Internal Revenue Code (the 401(k) Plan). The 401(k) Plan covers all employees who meet defined minimum age and service requirements and allows participants the option to elect to defer a portion of their annual compensation on a pretax basis, as well as Roth post tax deferrals. As currently designed, the Company is not required to make and has not made any contributions to the 401(k) Plan.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	15. Income Taxes For the years ended December 31, 2023 and 2022, the Company recorded current and deferred income tax expense of $0.3 million and $62 thousand, respectively. The Company’s effective tax rate of 0.6% differs from the U.S. statutory tax rate of 21.0% primarily as a result of the valuation allowance maintained against the Company’s net deferred tax assets. For financial reporting purposes, loss from operations before income taxes includes the following components (in thousands): Year Ended December 31, 2023 2022 Pretax loss: United States $ (53,430 ) $ (42,722 ) Foreign 5 (25 ) Loss before income taxes $ (53,425 ) $ (42,747 ) The components of our provision for income taxes during the two years ended December 31, 202 3 Year Ended 2023 2022 Current: Federal $ 316 $ —  State 1 —  Foreign 1 62 Total current 318 62 Deferred: Federal $ —  $ —  State —  —  Foreign —  —  Total deferred —  —  Total income tax provision $ 318 $ 62 A reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to income taxes as reflected in the financial statements is as follows: Year Ended 2023 2022 Federal income tax expense at statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 5.9 6.9 Permanent differences (1.2 ) (0.4 ) Convertible note revaluation (1.8 ) 0.0 Research and development tax credits 3.1 4.1 Change in valuation allowance (27.6 ) (31.6 ) Effective income tax rate (0.6 )% —  % Deferred taxes are recognized for temporary differences between the basis of assets and liabilities for financial statement and income tax purposes. The significant components of the Company’s deferred tax assets and liabilities consisted of the following (in thousands): 2023 2022 Deferred tax assets: Federal net operating loss carryforwards $ 13,412 $ 19,135 State net operating loss carryforwards 3,500 5,401 Contingent liability 14,876 —  Accruals and Reserves 818 659 Capitalized intangible assets 2,828 3,089 Tax credit carryforwards 5,762 4,745 Capitalized R&D expenditures 13,546 7,378 Lease liability 1,835 1,962 Stock compensation and other 544 318 Total gross deferred tax assets before valuation allowance 57,121 42,687 Less: Valuation allowance (55,078 ) (40,342 ) Net deferred tax assets 2,043 2,345 Deferred tax liabilities: Fixed assets (339 ) (483 ) Right of use asset (1,704 ) (1,862 ) Net deferred tax assets $ —  $ —  The Company had gross deferred tax assets before valuation allowances of $ million and $ million as of December 31, 2023 and 2022, respectively, principally attributable to net operating losses, the contingent liability and capitalized R&D expenditures. The Company has provided a valuation allowance for the full amount of the deferred tax assets as, based on all available evidence, it is considered more likely than not that all the recorded deferred tax assets will not be realized in a future period. The Company recorded an increase to the valuation allowance of $ million during the year ended December 31, 2023 due primarily to the contingent liability related to the termination of Horizon agreements which was recorded in 2023. As of December 31, 2023, the Company has $63.9 million of federal net operating loss carryforwards which can be carried forward indefinitely, and $55.4 million of state net operating loss carryforwards that expire at various dates beginning in 2040. Subject to the limitations described below, as of December 31, 2023, the Company had federal and state research and development tax credit carryforwards of $4.3 million and $1.8 million, respectively available to reduce future tax liabilities which start to expire in 2038. The Company has generated federal and state research and development credits but has not conducted a study to document the qualified activity. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed, and any adjustment is known, no amounts are being presented as uncertain tax position. A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the deferred tax asset established for the research and development credit carryforwards and the valuation allowance. Realization of the future tax benefits is dependent on many factors, including the Company’s ability to generate taxable income within the net operating loss carryforward period. 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 (IRS) and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50%, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. As a result of ownership changes in the Company from its inception through December 31, 2023, the Company’s NOL and tax credit carryforwards allocable to the periods preceding each such ownership change could be subject to limitations under IRC Section 382, however the Company has not yet completed an IRC Section 382 study. The Company files income tax returns in the United States, Australia and Massachusetts. The statute of limitations for assessment by the IRS and state tax authorities is closed prior to 2020, although carryforward attributes that were generated prior to tax year 2020 may still be adjusted upon examination by the IRS or state tax authorities if they either have been or will be used in a future period. The Company is currently not under examination by the IRS or any other jurisdictions for any tax years. The statute of limitations for assessment by the Australian Taxation Office is four years from the date of return filing. The Company is not currently under examination by the Australian Taxation Office for any tax years. The Company’s current intention is to permanently reinvest the total amount of its unremitted earnings in the local international jurisdiction. As such, the Company has not provided for taxes on the unremitted earnings of its international subsidiary. As of December 31, 2023, the Company’s foreign subsidiary does not have any unremitted foreign earnings. The Company establishes reserves for uncertain tax positions based on management’s assessment of exposures associated with tax positions taken on tax return filings. The tax reserves are analyzed periodically, and adjustments are made as events occur to warrant adjustments to the reserve. As of December , , the Company had gross unrecognized tax benefits. During the Company amended its prior year tax filings and settled the $ million unrecognized tax benefit that was previously recognized in the December , reporting period. The C ompany does not expect the unrecognized tax benefits to change significantly over the next months. The C ompany recognizes both interest and penalties associated with uncertain tax positions as a component of income tax expense. As of December , , the Company has not accrued penalties and provisions for interest.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	16. 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. The Company’s potentially dilutive securities, which include convertible preferred stock, convertible notes, 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 common shares 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 because including them would have had an anti-dilutive effect: Year Ended 2023 2022 Series A convertible preferred stock 47,628,788 47,628,788 Series A-1 6,500,000 6,500,000 Series B convertible preferred stock: 54,689,627 54,689,627 Options to purchase common stock 23,165,393 22,997,639 Warrants to purchase common stock 377,899 166,371 In addition, during the year ended December 31, 2022, the Company issued convertible notes with a principal balance of $30.0 million. These convertible notes and any accrued interest may convert into either a variable number of common shares or into shares of Series B preferred stock based on a fixed Exchange Ratio. Any shares of Series B preferred stock issued to settle the convertible notes would then be convertible into shares of common stock.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the date the financial statements are available to be issued for potential recognition or disclosure in the financial statements. The Company has completed an evaluation of all subsequent events after the audited balance sheet date of December 31, 2023 through March 26, 2024, the date the financial statements were issued, to ensure that these financial statements include appropriate disclosure of events both recognized in the financial statements as of December 31, 2023 and events which occurred subsequently but were not recognized in the financial statements. Amendment to Loan Agreement On March 21 million from March 31, 2024 to May 31, 2024. The date changes were adjusted to align the milestone in the Loan Agreement with closing of the Merger. On March 26, 2024, the Company received the first advance payment of $7.0 million per the terms of the Loan Agreement. Merger with Homology On March 25, 2024 the Company completed the Merger with Homology. See Note 1 for further discussion of the Merger. Stock Option Grants In March 2024, the Company granted under the 2024 Stock Option Plan, 0.9 million stock options to the officers, directors and other key members of management. Stock options were issued with an exercise price on the close of business on March 25, 2024. The stock option awards vest in accordance with terms typically grants under the 2024 Stock Option Plan.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in conformity with acco unt
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its wholly-owned
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the valuation of common stock awards, the valuation of convertible notes, the accruals of research and development expenses, the identification of material rights and estimation of standalone selling price for the identified performance obligations in the collaboration agreement and the inputs and assumptions to the over-time recognition of revenue under the collaboration agreement. Estimates are periodically reviewed considering changes in circumstances, facts and historical experience. Actual results may differ from the Company’s estimates.
Segment Information	Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision-making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer (CEO). The Company and the CEO view the Company’s operations and manage its business as one operating segment. All material long-lived assets of the Company reside in the United States.
Foreign Currency Transactions	Foreign Currency Transactions The Company’s functional currency is the United States dollar. Foreign currency transaction gains and losses are recorded in the statement of operations and comprehensive loss.
Concentrations of Credit Risk and Significant Suppliers	Concentrations of Credit Risk and Significant Suppliers Financial instruments that potentially expose the Company to credit risk primarily consist of cash, cash equivalents, restricted cash and restricted cash equivalents. The Company maintains its cash, cash equivalents, restricted cash and restricted cash equivalents balances with accredited financial institutions and, consequently, the Company does not believe it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The The Company is dependent on contract development and manufacturing organizations (CDMOs) to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients, other raw materials and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients, other raw materials and formulated drugs. The Company is also dependent on contract research organization (CROs) which provide services related to the research and development activities in its programs.
Off-Balance Sheet Risk	Off-Balance As of December 31, 2023 and 2022, the Company had no off-balance-sheet
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: Level 1 – Level 2 – Level 3 –
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the respective assets. Major additions and betterments are capitalized; maintenance and repairs, which do not improve or extend the life of the respective assets, are charged to operations as incurred. Upon retirement or sale, the cost and related accumulated depreciation Estimated Useful Life (Years) Lab equipment 5 Furniture and fixtures 3 Computer equipment 3 Leasehold improvements Shorter of useful life or term of associated lease
Leases	Leases The Company evaluates whether an arrangement is or contains a lease at contract inception. If a contract is or contains a lease, lease classification is determined at lease commencement, which represents the date at which the underlying asset is made available for use by the Company. The Company’s lease terms are generally measured at the respective lease’s noncancelable term and exclude any optional extension terms as the Company is not reasonably certain to exercise such options. The Company elected the short-term lease exemption and therefore does not recognize lease liabilities and right of use assets for lease arrangements with the original lease terms of twelve months or less. Lease liabilities represent the Company’s obligation to make lease payments under a lease arrangement. Lease liabilities are measured as the present value of fixed lease payments, discounted using an incremental borrowing rate, as interest rates implicit in the Company’s lease arrangements are generally not readily determinable. The Company elected the practical expedient to not separate lease and non-lease The incremental borrowing rate represents the interest rate at which the Company could borrow a fully collateralized amount equal to the lease payments, over a similar term, in a similar economic environment. The Company determines the incremental borrowing rate at lease commencement, generally using a synthetic credit rating based on the Company’s financial position and negative cash flows, factoring in adjustments for additional risks based on the Company’s economic condition, a survey of comparable companies with similar credit and financial profiles, as well as additional market risks, as may be applicable. Right-of-use Right-of-use right-of-use right-of-use
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash with maturities of three months or less at the date of purchase to be cash equivalents. The Company maintains its cash in bank deposits accounts that are FDIC insured up the $250,000. At times, the Company’s bank accounts may exceed the federal insurance limits. Cash equivalents are comprised of money market accounts invested in U.S. Treasury securities. Restricted cash and restricted cash equivalents are comprised of deposits held by financial institutions as collateral for the company’s venture debt and used to collateralize letters of credit related to the Company’s lease arrangements. The C beginning-of-period end-of-period Cash, cash equivalents, restricted cash and restricted cash equivalents consisted of the following (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 25,617 $ 43,893 Restricted cash and cash equivalents 5,647 5,647 Total cash, cash equivalents, restricted cash and restricted cash equivalents $ 31,264 $ 49,540
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company continually monitors events and changes in circumstances that could indicate carrying amounts of long-lived assets may be impaired, and assesses their recoverability based upon estimated future undiscounted future cash flows expected to be generated by the long-lived assets. If the estimated aggregate undiscounted cash flows are less than the carrying amount of the long-lived assets, an impairment charge, calculated as the amount by which the carrying amount of the assets exceeds the estimated fair value of the assets, is recorded. The estimated fair value of the long-lived assets is determined based on the estimated discounted cash flows expected to be generated from the long-lived assets.
Convertible notes	Convertible notes During 2022, the Company recognized a liability as a result of the issuance of convertible promissory notes (the Convertible Notes). The Company accounts for all Convertible Notes issued under the fair value option election of ASC 825, Financial Instruments
Debt and Warrant Issuance Costs	Debt and Warrant Issuance Costs The carrying value of the Company’s venture debt was recorded net of issuance costs and discount relating to the issuance of warrants. The amounts are amortized over the term of the debt using the effective interest method and recognized as interest expense.
Convertible Preferred Stock	Convertible Preferred Stock The Company records all convertible preferred stock upon issuance at its respective fair value or original issuance price less issuance costs, as stipulated by its terms. The Company classifies its convertible preferred stock outside of stockholders’ deficit as the redemption of such shares is outside the Company’s control in certain circumstances, including upon liquidation or sale, as holders of the convertible preferred shares could cause redemption of the shares in these situations. The Company does not adjust the carrying value of the convertible preferred stock to redemption value until the contingent events that could give rise to redemption are considered probable of occurring.
Revenue Recognition	Revenue Recognition Under ASC Topic 606, Revenue from Contracts with Customers steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer. Once a contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The identification of material rights requires judgments related to the determination of the value of the underlying good or service relative to the option exercise price. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company assesses whether each promised good or service is distinct for the purpose of identifying the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). In assessing whether a promised good or service is distinct, the Company considers factors such as the license terms, the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, an entity is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct. The transaction price is determined and allocated to the identified performance obligations in proportion to their stand-alone selling prices (SSP) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. Determining the SSP for performance obligations requires significant judgment. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple performance obligations. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The amount of variable consideration included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty related to the variable consideration is resolved. At the end of each subsequent reporting period, the Company re-evaluates catch-up adjustment. If an arrangement includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time, and if over time recognition is based on the use of an output or input method.
Collaboration Arrangement	Collaboration Arrangement The Company analyzes first its collaboration arrangement to assess whether it is within the scope of FASB ASC Topic 808, Collaborative Arrangements (ASC 808) to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. To the extent the arrangement is within the scope of ASC 808, the Company assesses whether aspects of the arrangement between the Company and its collaboration partner are within the scope of other accounting literature, including ASC 606. If it is concluded that some or all aspects of the arrangement represent a transaction with a customer, the Company will account for those aspects of the arrangement within the scope of ASC 606. ASC 808 provides guidance for the presentation and disclosure of transactions in collaborative arrangements, but it does not provide recognition or measurement guidance. Therefore, if the Company concludes a counterparty to a transaction is not a customer or otherwise not within the scope of ASC 606, the Company considers the guidance in other accounting literature, including the guidance in ASC 606, as applicable or by analogy to account for such transaction. The classification of transactions under the Company’s arrangements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and Development expenses are comprised of costs incurred in performing research and development activities, including salaries, stock-based compensation and benefits, costs for clinical research organizations and other outsourced activities; laboratory supplies; technology licenses, software and other information technology support; facilities and depreciation. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development expenses in the period in which they are incurred. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed. The Company has entered into various research and development related contracts with external parties. The payments under these agreements are recorded as research and development expenses as the underlying services are performed or the goods are received. The Company records accrued liabilities for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued and prepaid balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.
Research and Development Tax Incentive	Research and Development Tax Incentive The Company is eligible under the AusIndustry Research and Tax Development Tax Incentive Program to obtain a cash amount from the Australian Taxation Office (ATO). The tax incentive is available to the Company on the basis of specific criteria with which the Company must comply related to research and development expenditures in Australia. The Company adopted on January 1, 2022, ASU No. 2021-10, Government Assistance (Topic 832): Disclosures by Business Entities about Government Assistance
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 statement of operations.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based awards in accordance with ASC Topic 718, Compensation – Stock Compensation The Company’s equity incentive plan allows for the issuance of restricted stock awards to employees and non-employee
Determination of Fair Value of Common Stock on Grant Dates	Determination of Fair Value of Common Stock on Grant Dates The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model, which requires inputs based on certain subjective assumptions, including the fair value of the Company’s common stock, expected stock price volatility, the expected term of the award, the risk-free interest rate, and expected dividends (see Note 11). The Company has been a private company and lacks company-specific historical and implied volatility information for its stock. Therefore, it estimates its expected stock price volatility based on the historical volatility of publicly traded peer companies. The expected term of options was calculated using the simplified method, which represents the average of the contractual term of the option and the weighted-average vesting period of the option. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate expected term. The expected term of options granted to non-employees Due to the absence of an active market for the Company’s common stock, the Company and the board of directors were required to determine the fair value of the Company’s common stock at the time of each grant of a stock-based award. The Company estimated the fair value of its common stock utilizing methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation The Company classifies stock-based compensation expense in its statements of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.
Income Taxes	Income Taxes Income taxes are recorded in accordance with FASB ASC Topic 740, Income Taxes statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. Should the actual amounts differ from these estimates, the amount of the Company’s valuation allowance could be materially impacted. Changes in these estimates may result in significant increases or decreases to the tax provision in a period in which such estimates are changed, which in turn would affect net income or loss. Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step more-likely-than-not
Comprehensive Income (Loss)	Comprehensive Income (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. There was no difference between net loss and comprehensive loss for each of the periods presented in the accompanying financial statements.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Net loss per share attributable to common stockholders is determined using the two-class Diluted net loss per share is computed using the more dilutive of (a) the two-class if-converted average number of common shares included in the computation of diluted net loss gives effect to all potentially dilutive common equivalent shares, including outstanding stock options and preferred stock. Common stock equivalent shares are excluded from the computation of diluted net loss per share if their effect is antidilutive. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is generally the same as basic net loss per share attributable to common stockholders since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Deferred Transaction Costs	Deferred Transaction Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process paid-in in-process
Subsequent Event Considerations	Subsequent Event Considerations The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated events occurring after the date of its consolidated balance sheet through March 26, 2024, the date of these consolidated financial statements were available to be issued. See Note 17.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that are 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 financial position or results of operations upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) – Measurement of Credit Losses on Financial Instruments, In August 2020, the FASB issued ASU No. 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity’s Own Equity (Subtopic 815-40) Recently Issued Accounting Standards Not Yet Adopted In November 2023, the FASB issued Accounting Standards Update 2023-07, Segment Reporting (Topic 280: Improvements to Reportable Segment Disclosures (“ASU 2023-07”)) On December 14, 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740)—Improvements to Income Tax Disclosures No. 2023-09 2023-09

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Estimated Useful Life of Assets	Estimated Useful Life (Years) Lab equipment 5 Furniture and fixtures 3 Computer equipment 3 Leasehold improvements Shorter of useful life or term of associated lease
Summary of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	Cash, cash equivalents, restricted cash and restricted cash equivalents consisted of the following (in thousands): December 31, 2023 2022 Cash and cash equivalents $ 25,617 $ 43,893 Restricted cash and cash equivalents 5,647 5,647 Total cash, cash equivalents, restricted cash and restricted cash equivalents $ 31,264 $ 49,540

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis	Financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2023 are summarized as follows (in thousands): Description Balance as of December 31, 2023 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Assets Cash equivalents: Money market funds $ 24,100 $ 24,100 $ —  $ —  Restricted cash equivalents: Money market funds 5,000 5,000 —  —  Total $ 29,100 $ 29,100 $ —  $ —  Liabilities Convertible Notes $ 38,595 $ —  $ —  $ 38,595 Total $ 38,595 $ —  $ —  $ 38,595 Financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2022 are summarized as follows (in thousands): Description Balance as of December 31, 2022 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) Assets Cash equivalents: Money market funds $ 42,496 $ 42,496 $ —  $ —  Restricted cash equivalents: Money market funds 5,000 5,000 —  —  Total $ 47,496 $ 47,496 $ —  $ —  Liabilities Convertible Notes $ 32,402 $ —  $ —  $ 32,402 Total $ 32,402 $ —  $ —  $ 32,402
Summary of Fair Value Measurement Significant Inputs	Year ending December 31, 2023 Scenario 1 Scenario 2 Scenario 3 Probability of each scenario 80.0 % 15.0 % 5.0 % Expected Term (years) 0.25 0.25 0.42 Required market rates of return 15.0 % 15.0 % 15.0 %

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property Plant and Equipment	Property and equipment, net consisted of the following as of (in thousands): December 31, 2023 2022 Lab equipment $ 1,382 $ 1,382 Furniture and fixtures 341 341 Computer equipment 85 85 Leasehold improvements 940 935 Total property and equipment 2,748 2,743 Less accumulated depreciation (966 ) (467 ) Property and equipment, net $ 1,782 $ 2,276

Prepaid Expenses, Other Curre_2

Prepaid Expenses, Other Current Assets and Other Noncurrent Assets (Tables)	12 Months Ended
	Dec. 31, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Summary Of Prepaid Expenses And Other Current Assets	Prepaid expenses and other current assets consisted of the following as of (in thousands): December 31, 2023 2022 Payroll tax credit $ 755 $ 948 Prepaid external research and development 1,834 1,329 Research credit receivable —  116 Prepaid expenses 427 421 Other 83 146 Total prepaid expenses and other current assets $ 3,099 $ 2,960
Summary Of Prepaid Expenses And Other Nonurrent Assets	Other noncurrent assets consisted of the following as of (in thousands): December 31, 2023 2022 Deferred transaction costs $ 3,912 $ — Prepaid external research and development—long term 676 — Other 23 108 Total other noncurrent assets $ 4,611 $ 108

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following as of (in thousands): December 31, 2023 2022 Accrued external research and development $ 3,578 $ 4,077 Accrued compensation and related expenses 3,003 2,791 Accrued taxes payable 316 570 Operating lease liability 538 471 Accrued professional services and other 2,328 1,588 Total accrued expenses and other current liabilities $ 9,763 $ 9,497

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Amounts Reported In The Balance Sheet In Respect Of Operating Lease Assets And Corresponding Liabilities	Amounts reported in the consolidated balance sheet for leases where the Company is the lessee as of December 31, 2023 and 2022 were as follows (in thousands): December 31, 2023 2022 Assets: Operating lease right-of-use $ 6,301 $ 6,890 Total operating lease right-of-use $ 6,301 $ 6,890 Liabilities: Current: Operating lease liabilities $ 538 $ 471 Noncurrent: Operating lease liabilities, net of current portion 6,248 6,786 Total operating lease liabilities $ 6,786 $ 7,257
Schedule of Operating Lease Cost and Variable Lease Costs and Sub Lease Income	The following table summarizes operating lease costs for the years ended December 31, 2023 and 2022 (in thousands): December 31, 2023 2022 Fixed lease costs $ 999 $ 1,232 Variable lease costs 73 103 Total lease costs $ 1,072 $ 1,335
Schedule of Maturities of Operating Lease Liabilities	Minimum Rental Payments 2024 $ 1,029 2025 1,060 2026 1,092 2027 1,124 2028 1,158 Thereafter 3,687 Total minimum lease payments 9,150 Less imputed interest (2,364 ) Total lease liability $ 6,786 Lease liability, current portion $ 538 Lease liability, net of current portion 6,248 Total $ 6,786

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Summary of Long-term Debt Balance	The components of the long-term debt balance are as follows (in thousands): December 31, 2023 2022 Principal amount of term loans $ 5,500 $ 5,000 Unamortized debt discount and issuance costs (41 ) 72 Carrying amount 5,459 5,072 Less current portion (878 ) —  Long-term debt, net $ 4,581 $ 5,072

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2023
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Schedule of Shares of Common Stock For Future Issuance	The Company has reserved the following shares of common stock for future issuance: As of December 31, 2023 2022 Shares reserved upon the conversion of authorized Series A preferred 47,628,788 47,628,788 Shares reserved upon the conversion of authorized Series A1 preferred 6,500,000 6,500,000 Shares reserved upon the conversion of authorized Series B preferred 54,689,627 54,689,627 Shares reserved for future issuance under the 2017 Stock Incentive Plan 1,167,685 1,669,058 Shares reserved upon the conversion of the convertible notes 29,853,711 —  Shares reserved for stock option exercises 23,165,393 22,997,639 Shares reserved for warrants 377,899 166,371 163,383,103 133,651,483

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of stock option activity	The following table summarizes the Company’s stock option activity under the 2017 Plan during the year ended December 31, 2023: Number of Weighted- Weighted- Aggregate Outstanding at December 31, 2022 22,997,639 $ 0.34 7.94 $ 362 Granted 3,221,672 0.52 —  Exercised (333,619 ) 0.32 —  Cancelled (2,720,299 ) 0.35 —  Outstanding at December 31, 2023 23,165,393 $ 0.36 6.87 $ 10,712 Exercisable at December 31, 2023 12,899,524 $ 0.33 5.36 $ 6,299
Schedule of stock options granted	The underlying assumptions used to value stock options granted using the Black-Scholes option-pricing model during the years ended December 31, 2023 and 2022 were as follows: Year Ended December 31, 2023 2022 Risk-free interest rate range 3.59% – 4.67% 1.74% – 3.90% Expected dividend rate —  —  Expected term (years) range 5.08 – 6.12 5.94 – 6.11 Expected stock price volatility range 88.9% – 94.0% 85.9% – 88.9%
Summary of stock based compensation expense	The Company recorded stock-based compensation expense in the following expense categories of its statements of operations (in thousands): Year Ended December 31,   2023     2022   Research and development $ 500 $ 447 General and administrative 929 791 Total stock-based compensation expense $ 1,429 $ 1,238

Agreements with Horizon (Tables

Agreements with Horizon (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue, Performance Obligation Satisfied over Time [Abstract]
Summary of the transaction price allocated to each performance obligation	The following table summarizes the allocation of the transaction price allocated to each performance obligation (in thousands): Transaction AD phase 2 research services $ 25,417 AA phase 2 research services 18,265 Material right for the purchase of ADX-914 11,318 Total $ 55,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of loss from operations before income taxes	For financial reporting purposes, loss from operations before income taxes includes the following components (in thousands): Year Ended December 31, 2023 2022 Pretax loss: United States $ (53,430 ) $ (42,722 ) Foreign 5 (25 ) Loss before income taxes $ (53,425 ) $ (42,747 )
Schedule of components of provision for income taxes	The components of our provision for income taxes during the two years ended December 31, 202 3 Year Ended 2023 2022 Current: Federal $ 316 $ —  State 1 —  Foreign 1 62 Total current 318 62 Deferred: Federal $ —  $ —  State —  —  Foreign —  —  Total deferred —  —  Total income tax provision $ 318 $ 62
Schedule of reconciliation of income tax expense (benefit) computed	A reconciliation of income tax expense (benefit) computed at the statutory federal income tax rate to income taxes as reflected in the financial statements is as follows: Year Ended 2023 2022 Federal income tax expense at statutory rate 21.0 % 21.0 % State income taxes, net of federal benefit 5.9 6.9 Permanent differences (1.2 ) (0.4 ) Convertible note revaluation (1.8 ) 0.0 Research and development tax credits 3.1 4.1 Change in valuation allowance (27.6 ) (31.6 ) Effective income tax rate (0.6 )% —  %
Schedule of deferred taxes	Deferred taxes are recognized for temporary differences between the basis of assets and liabilities for financial statement and income tax purposes. The significant components of the Company’s deferred tax assets and liabilities consisted of the following (in thousands): 2023 2022 Deferred tax assets: Federal net operating loss carryforwards $ 13,412 $ 19,135 State net operating loss carryforwards 3,500 5,401 Contingent liability 14,876 —  Accruals and Reserves 818 659 Capitalized intangible assets 2,828 3,089 Tax credit carryforwards 5,762 4,745 Capitalized R&D expenditures 13,546 7,378 Lease liability 1,835 1,962 Stock compensation and other 544 318 Total gross deferred tax assets before valuation allowance 57,121 42,687 Less: Valuation allowance (55,078 ) (40,342 ) Net deferred tax assets 2,043 2,345 Deferred tax liabilities: Fixed assets (339 ) (483 ) Right of use asset (1,704 ) (1,862 ) Net deferred tax assets $ —  $ —

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Summary of computation of diluted net loss per share attributable to common stockholders	The Company excluded the following from the computation of diluted net loss per share attributable to common stockholders because including them would have had an anti-dilutive effect: Year Ended 2023 2022 Series A convertible preferred stock 47,628,788 47,628,788 Series A-1 6,500,000 6,500,000 Series B convertible preferred stock: 54,689,627 54,689,627 Options to purchase common stock 23,165,393 22,997,639 Warrants to purchase common stock 377,899 166,371

Nature of the Business - Additi

Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 25, 2024	Dec. 31, 2023	Dec. 31, 2022	Nov. 16, 2023
Nature Of Business [Line Items]
Common stock shares subscribed				42,000,000
Net income (loss)		$ (53,743)	$ (42,809)
Accumulated deficit		(187,081)	(133,338)
Cash and cash equivalents		25,617	$ 43,893
Proceeds from issuance of common stock		42,000
Homology [Member]
Nature Of Business [Line Items]
Cash and cash equivalents		61,300
Parent company [Member]
Nature Of Business [Line Items]
Cash and cash equivalents		$ 25,600
Subsequent event [Member] | Homology [Member]
Nature Of Business [Line Items]
Business combination shares conversion into rights to purchase common stock	1,682,045
Stockholders' equity, reverse stock split	one-for-eighteen
Outstanding common stock of the combined company	74.40%
Conversion of Stock, Shares Converted	7,017,842

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Line Items]
Cash FDIC insured amount	$ 250,000
Research and development	0	$ 400,000
Deferred transaction costs	3,912,000	0
Foreign exchange contracts & other forign heding arrangements [Member]
Accounting Policies [Line Items]
Off-balance-sheet risk	$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Estimated Useful Life of Assets (Detail)	12 Months Ended
	Dec. 31, 2023
Lab equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	5 years
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Computer equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life (Years)	3 years
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeTermOfLeaseMember
Estimated Useful Life (Years)	Shorter of useful life or term of associated lease

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 25,617	$ 43,893
Restricted cash and cash equivalents	5,647	5,647
Total	$ 31,264	$ 49,540	$ 32,894

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 25,617	$ 43,893
Restricted cash equivalents	5,647	5,647
Total	31,264	49,540	$ 32,894
Convertible notes	0	32,402
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	29,100	47,496
Convertible notes	38,595	32,402
Total	38,595	32,402
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	24,100	42,496
Restricted cash equivalents	5,000	5,000
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	29,100	47,496
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	24,100	42,496
Restricted cash equivalents	5,000	5,000
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible notes	38,595	32,402
Total	$ 38,595	$ 32,402

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value Measurement Significant Inputs (Detail)	Dec. 31, 2023 yr
Probability of each scenario [Member] | Scenario one [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	80
Probability of each scenario [Member] | Scenario two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	15
Probability of each scenario [Member] | Scenario three [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	5
Expected Term (years) [Member] | Scenario one [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	0.25
Expected Term (years) [Member] | Scenario two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	0.25
Expected Term (years) [Member] | Scenario three [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	0.42
Required market rates of return [Member] | Scenario one [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	15
Required market rates of return [Member] | Scenario two [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	15
Required market rates of return [Member] | Scenario three [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	15

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands				12 Months Ended
	Dec. 23, 2022	Aug. 05, 2022	May 20, 2022	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Proceeds from Convertible Debt	$ 16,700	$ 5,000	$ 8,300	$ 0	$ 30,000
Convertible debt, fair value disclosures				38,600
Interest expense				1,500
Fair value Of Interest Expenses				$ 4,700

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant and Equipment [Line Items]
Property and equipment, at cost	$ 2,748	$ 2,743
Less accumulated depreciation	(966)	(467)
Property and equipment, net	1,782	2,276
Lab equipment [Member]
Property Plant and Equipment [Line Items]
Property and equipment, at cost	1,382	1,382
Furniture and fixtures [Member]
Property Plant and Equipment [Line Items]
Property and equipment, at cost	341	341
Computer equipment [Member]
Property Plant and Equipment [Line Items]
Property and equipment, at cost	85	85
Leasehold improvements [Member]
Property Plant and Equipment [Line Items]
Property and equipment, at cost	$ 940	$ 935

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation	$ 499	$ 370
Impairment, long-lived asset, held-for-use	0	0
Loss on disposal of property and equipment	0	23
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation	$ 499	$ 370

Prepaid Expenses, Other Curre_3

Prepaid Expenses, Other Current Assets and Other Noncurrent Assets - Summary Of Prepaid Expenses And Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Payroll tax credit	$ 755	$ 948
Prepaid external research and development	1,834	1,329
Research credit receivable	0	116
Prepaid expenses	427	421
Other	83	146
Total prepaid expenses and other current assets	$ 3,099	$ 2,960

Prepaid Expenses, Other Curre_4

Prepaid Expenses, Other Current Assets and Other Noncurrent Assets - Summary Of Prepaid Expenses And Other Nonurrent Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Noncurrent [Abstract]
Deferred transaction costs	$ 3,912	$ 0
Prepaid external research and development—long term	676	0
Other	23	108
Total other noncurrent assets	$ 4,611	$ 108

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Nov. 16, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued external research and development	$ 3,578	$ 4,077
Accrued compensation and related expenses	3,003	$ 2,791
Accrued taxes payable	316		$ 570
Operating lease liability, current	538		471
Accrued professional services and other	2,328		1,588
Total accrued expenses and other current liabilities	$ 9,763		$ 9,497
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Expenses And Other Current Liabilities		Accrued Expenses And Other Current Liabilities

Commitments and Contingencies

Commitments and Contingencies Summary of Amounts Reported in the Balance Sheet in Respect of Operating Lease Assets and Corresponding Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets:
Operating lease right-of-use assets	$ 6,301	$ 6,890
Current:
Operating lease liabilities	538	471
Noncurrent:
Operating lease liabilities, net of current portion	6,248	6,786
Total operating lease liabilities	$ 6,786	$ 7,257

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Operating Lease Cost and Variable Lease Costs and Sub Lease Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Fixed lease costs	$ 999	$ 1,232
Variable lease costs	73	103
Total lease costs	$ 1,072	$ 1,335

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Maturities of Operating Lease Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
2024	$ 1,029
2025	1,060
2026	1,092
2027	1,124
2028	1,158
Thereafter	3,687
Total minimum lease payments	9,150
Less imputed interest	(2,364)
Total operating lease liabilities	6,786	$ 7,257
Lease liability, current portion	538	471
Lease liability, net of current portion	6,248	6,786
Total	$ 6,786	$ 7,257

Commitments and Contingencies_3

Commitments and Contingencies - Additional Information (Detail) $ in Thousands		1 Months Ended	4 Months Ended	12 Months Ended
	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2021 USD ($) ft²	Dec. 31, 2019 USD ($) shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)
Commitment And Contingencies [Line Items]
Research and development expenses				$ 31,729	$ 35,814
Executive insurance reserve				5,000
License Agreement With The University Of Colorado [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable				$ 2,200
Percentage of sublicense fees				15%
Period of obligation to pay royalties				20 years
Research and development expenses				$ 0	50
License Agreement With Bristol Mayers Equib Company [Member]
Commitment And Contingencies [Line Items]
Percentage of sublicense fees			60%
Period of obligation to pay royalties			12 years
Upfront payment made			$ 8,000
Commercial milestone payment payable			$ 215,000			$ 215,000
Royalty as a percentage of sales			10%
In process research and development expense recognized						14,600
License Agreement With Bristol Mayers Equib Company [Member] | Cash Consideration [Member]
Commitment And Contingencies [Line Items]
In process research and development expense recognized						8,000
License Agreement With Bristol Mayers Equib Company [Member] | Temporary Equity [Member]
Commitment And Contingencies [Line Items]
In process research and development expense recognized						6,600
License Agreement With Bristol Mayers Equib Company [Member] | Maximum [Member] | Tranche One [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable			$ 49,000			49,000
License Agreement With Bristol Mayers Equib Company [Member] | Maximum [Member] | Tranche Two [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable							$ 49,000
License Agreement With Bristol Mayers Equib Company [Member] | Maximum [Member] | Tranche Three [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable							49,000
License Agreement With Bristol Mayers Equib Company [Member] | Minimum [Member] | Tranche One [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable			$ 32,000			$ 32,000
License Agreement With Bristol Mayers Equib Company [Member] | Minimum [Member] | Tranche Two [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable							32,000
License Agreement With Bristol Mayers Equib Company [Member] | Minimum [Member] | Tranche Three [Member]
Commitment And Contingencies [Line Items]
Development and sales milestone payment payable							$ 32,000
License Agreement With Bristol Mayers Equib Company [Member] | Series A Redeemable Preferred Stock [Member]
Commitment And Contingencies [Line Items]
Stock issued during period shares purchase of assets | shares			6,628,788
Waltham Massauchets [Member]
Commitment And Contingencies [Line Items]
Office space leased | ft²	15,000	15,000
Operating lease expiration year and month	2031-12
Lessee, operating lease, lease not yet commenced, renewal term	5 years	5 years
Sublease aggregate base rent obligation	$ 970	$ 970
Percentage increase in initial annual base rent per square foot.		3%
Annual Rent Operating lease Aggregate After Increase		$ 11,100
Security deposit					647
Operating lease weighted average remaining lease term				8 years
Operating lease weighted average discount rate				7.50%
Waltham Massauchets [Member] | Restricted Cash And Cash Equivalents Non Current [Member]
Commitment And Contingencies [Line Items]
Lessee tenant improvement allowance					$ 400

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)

1 Months Ended

12 Months Ended

Mar. 25, 2024

Nov. 02, 2023

Jul. 12, 2023

Dec. 23, 2022

Dec. 21, 2022

Aug. 10, 2022

Aug. 05, 2022

Jun. 30, 2022

May 20, 2022

Dec. 11, 2020

Dec. 31, 2020

Dec. 31, 2023

Dec. 31, 2022

Apr. 26, 2023

Aug. 01, 2020

Debt Instrument [Line Items]

Proceeds from long term line of credit

$ 5,500,000

$ 0

Line of credit facility outstanding current

878,000

0

Class of warrants or rights number of securities covered by warrants or rights

17,318,383

Proceeds from convertible debt

$ 16,700,000

$ 5,000,000

$ 8,300,000

0

30,000,000

Interest expenses on convertible debt

1,500,000

Convertible debt at fair value

38,600,000

Proceeds from Issuance Initial Public Offering

50,000,000

Two Thousand And Twenty And Two Thousand And Twenty Three Term A Loan [Member]

Debt Instrument [Line Items]

Interest expenses

$ 531,000

$ 327,000

Debt instrument effective rate of interest percentage

10.42%

9.49%

Convertible Debt Agreement [Member]

Debt Instrument [Line Items]

Debt instrument face value

$ 30,000,000

Convertible debt interest rate percentage

5%

Interest expenses on convertible debt

$ 1,500,000

$ 376,000

Debt instrument conversion price percentage

90%

Convertible Debt Agreement [Member] | Other Nonoperating Income (Expense) [Member]

Debt Instrument [Line Items]

Interest expenses on convertible debt

1,500,000

Gain loss due to change in fair value of convertible debt

4,700,000

Convertible Debt Agreement [Member] | Series B Redeemable Convertible Preferred Stock [Member]

Debt Instrument [Line Items]

Debt instrument conversion price per share

$ 1.0971

Convertible Debt Agreement [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Debt instrument converted into equity number of shares issued

29,853,711

Convertible Debt Agreement [Member] | Current Liabilities [Member]

Debt Instrument [Line Items]

Convertible debt at fair value

$ 38,600,000

$ 32,400,000

Loan And Security Agreement With Silicon Valley Bank [Member]

Debt Instrument [Line Items]

Class of warrants or rights number of securities covered by warrants or rights

166,371

Class of warrants or rights exercise price per share

$ 0.33

Class of warrants or rights term

10 years

Loan And Security Agreement With Silicon Valley Bank [Member] | Warrants Issued To Silicon Valley Bank [Member]

Debt Instrument [Line Items]

Fair value of warrants issued

$ 39,000

Loan And Security Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member]

Debt Instrument [Line Items]

Line of credit maximum borrowing capacity

25,000,000

Proceeds from long term line of credit

5,000,000

Line of credit remaining borrowing capacity

$ 20,000,000

Long term debt variable interest rate percentage

3.25%

Line of credit facility date of first required payment

Jul. 01, 2022

Line of credit facility expiration date

Dec. 01, 2023

Line of credit facility commitment fee amount

$ 91,000

Line of credit facility commitment fee percentage

2%

Long term debt balloon payment percentage

2%

Loan And Security Second Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member]

Debt Instrument [Line Items]

Line of credit facility expiration date

Dec. 31, 2024

Long term debt balloon payment percentage

4%

Line of credit facility frequency of payments

24 equal monthly payments of principal plus interest.

Loan And Security Third Amendment Agreement With Silicon Valley Bank [Member]

Debt Instrument [Line Items]

Tranferred to restricted cash collateral

$ 5,000,000

Loan And Security Third Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member] | Restricted Cash Non Current [Member]

Debt Instrument [Line Items]

Debt instrument collateral given

$ 5,000,000

Loan And Security Fourth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member]

Debt Instrument [Line Items]

Line of credit facility expiration date

Dec. 01, 2024

Debt instrument terms of payment

18 equal monthly payments of principal plus interest.

Loan And Security Fifth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member]

Debt Instrument [Line Items]

Percentage of consolidated cash to be maintained with the lender

50%

Unrestricted and unencumbered cash percentage to be maintained

100%

Percentage of outstanding debt to be maintained with the lender by way of cash

110%

Sixth Amendment Agreement With Silicon Valley Bank [Member]

Debt Instrument [Line Items]

Class of warrants or rights number of securities covered by warrants or rights

211,528

Class of warrants or rights exercise price per share

$ 0.36

Class of warrants or rights term

10 years

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Tranche One Milestone [Member]

Debt Instrument [Line Items]

Class of warrants or rights number of securities covered by warrants or rights

105,764

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Tranche Two Milestone [Member]

Debt Instrument [Line Items]

Class of warrants or rights number of securities covered by warrants or rights

105,764

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Term A Loan Advance [Member]

Debt Instrument [Line Items]

Line of credit facility outstanding current

$ 5,000,000

Long term debt balloon payment

$ 200,000

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member]

Debt Instrument [Line Items]

Debt instrument terms of payment

The interest-only period extends through June 30, 2024 followed by 36 equal monthly payments of principal plus interest.

Line of credit facility aggregate amount including balloon repayment payable

$ 5,500,000

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member] | Prime Rate [Member]

Debt Instrument [Line Items]

Long term debt variable interest rate percentage

8%

Debt instrument variable interest spread

0.25%

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member] | Before Thirty First Of March Two Thousand And Twenty Four [Member]

Debt Instrument [Line Items]

Line of credit facility amount that may be contingently borrowed

$ 7,000,000

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member] | Before Thirty First Of March Two Thousand And Twenty Five [Member]

Debt Instrument [Line Items]

Line of credit facility amount that may be contingently borrowed

7,500,000

Sixth Amendment Agreement With Silicon Valley Bank [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member] | Before Thirty First Of March Two Thousand And Twenty Six [Member]

Debt Instrument [Line Items]

Line of credit facility amount that may be contingently borrowed

$ 5,000,000

Seventh Amendment To The Loan Agreement [Member] | Two Thousand And Twenty Three Term A Loan Advance [Member] | Before Thirty First Of March Two Thousand And Twenty Four [Member]

Debt Instrument [Line Items]

Face value of debt instrument that may be contingently borrowed

$ 7,000,000

Estimated aggregate proceeds from debt and equity

75,000,000

Estimated aggregate proceeds from equity

$ 37,500,000

Debt - Summary of Long-term Deb

Debt - Summary of Long-term Debt Balance (Detail) - Venture Debt Two Thousand Twenty And Two Thousand And Twenty Three Term A Loan [Member] - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Disclosure in tabular form of venture debt [Line Items]
Principal amount of term loans	$ 5,500	$ 5,000
Unamortized debt discount and issuance costs	(41)	72
Carrying amount	5,459	5,072
Less current portion	(878)	0
Long-term debt, net	$ 4,581	$ 5,072

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Detail) $ / shares in Units, $ in Thousands				1 Months Ended			2 Months Ended	12 Months Ended
	Mar. 25, 2024 USD ($) shares	Oct. 15, 2020 USD ($) $ / shares shares	Aug. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Aug. 31, 2019 USD ($) $ / shares shares	Jul. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2023 USD ($) Directors $ / shares	Dec. 31, 2022 USD ($)	Nov. 01, 2021 $ / shares	Aug. 01, 2020 shares
Temporary Equity [Line Items]
Class of warrants or rights number of securities covered by warrants or rights | shares											17,318,383
Common Stock [Member] | Subsequent event [Member]
Temporary Equity [Line Items]
Temporary equity converted into permanent equity value	$ 11
Additional Paid-in Capital [Member] | Subsequent event [Member]
Temporary Equity [Line Items]
Temporary equity converted into permanent equity value	$ 111,400
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares						10,000,000
Sale of stock issue price per share | $ / shares						$ 1		$ 1
Temporary equity stock issuance costs						$ 100
Proceeds from redeemable convertible preferred stock						$ 9,900
Class of warrants or rights number of securities covered by warrants or rights | shares						31,000,000
Number of directors entitled to be elected | Directors								3
Temporary equity conversion price per share | $ / shares								$ 1
Temporary equity dividend rate								6%	6%
Temporary equity, dividends, adjustment								$ 0	$ 0
Series A Redeemable Convertible Preferred Stock [Member] | License Agreement With Bristol Mayers Equib Company [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares				6,628,788
Series A Redeemable Convertible Preferred Stock [Member] | Achievement Of Specified Milestones [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares					3,000,000
Sale of stock issue price per share | $ / shares					$ 1
Temporary equity stock issuance costs					$ 30
Proceeds from redeemable convertible preferred stock					$ 2,970
Series A Redeemable Convertible Preferred Stock [Member] | Upon Receipt Of Waiver Of Milestone Conditions [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares				28,000,000
Sale of stock issue price per share | $ / shares				$ 1
Temporary equity stock issuance costs				$ 40
Proceeds from redeemable convertible preferred stock				$ 27,960
Series A One Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares						6,500,000
Sale of stock issue price per share | $ / shares								$ 0.885
Temporary equity conversion price per share | $ / shares								$ 0.885
Temporary equity dividend rate								6%	6%
Temporary equity, dividends, adjustment								$ 0	$ 0
Series A One Redeemable Convertible Preferred Stock [Member] | Subsequent event [Member]
Temporary Equity [Line Items]
Conversion of temporary equity into permanent equity shares | shares	47,628,788
Series A Two Redeemable Convertible Preferred Stock [Member] | Subsequent event [Member]
Temporary Equity [Line Items]
Conversion of temporary equity into permanent equity shares | shares	6,500,000
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares		1,822,987	34,636,767
Sale of stock issue price per share | $ / shares		$ 1.0971	$ 1.0971					$ 1.0971
Temporary equity stock issuance costs			$ 100
Proceeds from redeemable convertible preferred stock		$ 2,000	$ 37,900				$ 20,000
Number of directors entitled to be elected | Directors								2
Temporary equity conversion price per share | $ / shares								$ 1.0971
Temporary equity dividend rate								6%	6%
Temporary equity, dividends, adjustment								$ 0	$ 0
Series B Redeemable Convertible Preferred Stock [Member] | Subsequent event [Member]
Temporary Equity [Line Items]
Conversion of temporary equity into permanent equity shares | shares	54,689,627
Series B Redeemable Convertible Preferred Stock [Member] | Achievement Of Specified Milestones [Member]
Temporary Equity [Line Items]
Stock issued during the period new issues | shares							18,229,873
Sale of stock issue price per share | $ / shares										$ 1.0971
Temporary equity stock issuance costs							$ 10

Common Stock - Schedule of Shar

Common Stock - Schedule of Shares of Common Stock For Future Issuance (Detail) - shares	Dec. 31, 2023	Dec. 31, 2022
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	163,383,103	133,651,483
Shares reserved for warrants [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	377,899	166,371
Shares reserved for stock option exercises [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	23,165,393	22,997,639
Shares reserved upon the conversion of the convertible notes [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	29,853,711	0
Shares reserved for future issuance under the 2017 Stock Incentive Plan [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	1,167,685	1,669,058
Shares reserved upon the conversion of authorized Series A preferred stock [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	47,628,788	47,628,788
Shares reserved upon the conversion of authorized Series A1 preferred stock [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	6,500,000	6,500,000
Shares reserved upon the conversion of authorized Series B preferred stock [Member]
Disclosure In Tabular Form Of Common Stock Shares Reserved For Future Issuance [Line Items]
Common Stock Capital Shares Reserved for Future Issuance	54,689,627	54,689,627

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - $ / shares	Dec. 31, 2023	Nov. 16, 2023	Dec. 31, 2022	Dec. 08, 2022	May 20, 2022
Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract]
Common stock shares authorized	225,000,000		141,900,000
Common stock par value per share	$ 0.0001		$ 0.0001
Common stock additional number of shares authorized		83,100,000		6,900,000	5,000,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Aggregate Intrinsic Value, Outstanding Ending Balance	$ 10,712	$ 362
Aggregate Intrinsic Value, Exercisable	$ 6,299
Two Thousand Seventeen Stock Option and Grant Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Outstanding at Beginning Balance	22,997,639
Number of Shares, Granted	3,221,672
Number of Shares, Exercised	(333,619)
Number of Shares, Cancelled	(2,720,299)
Number of Shares, Outstanding at Ending Balance	23,165,393	22,997,639
Number of Shares, Exercisable	12,899,524
Weighted- Average Exercise Price, Outstanding at Beginning Balance	$ 0.34
Weighted- Average Exercise Price, Granted	0.52
Weighted- Average Exercise Price, Exercised	0.32
Weighted- Average Exercise Price, Cancelled	0.35
Weighted- Average Exercise Price, Outstanding at Ending Balance	0.36	$ 0.34
Weighted- Average Exercise Price, Exercisable	$ 0.33
Weighted Average Remaining Contractual Term, Outstanding	6 years 10 months 13 days	7 years 11 months 8 days
Weighted Average Remaining Contractual Term, Exercisable	5 years 4 months 9 days

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Options Granted (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate range, minimum	3.59%	1.74%
Risk-free interest rate range, maximum	4.67%	3.90%
Expected dividend rate	0%	0%
Expected stock price volatility range, minimum	88.90%	85.90%
Expected stock price volatility range, maximum	94%	88.90%
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years) range	6 years 1 month 13 days	6 years 1 month 9 days
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (years) range	5 years 29 days	5 years 11 months 8 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 1,429	$ 1,238
Research and development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	500	447
General and administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 929	$ 791

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based awards, Common stock reserved for issuance	163,383,103	133,651,483
Number of stock awards issued	$ 0	$ 0
Unrecognised compensation cost, recognition period	2 years 6 months
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares subject to repurchase	0
Fair value of restricted stock awards vested	$ 0
Unrecognised compensation cost	$ 0
Restricted Stock [Member] | Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based awards, vesting period	4 years
Restricted Stock [Member] | Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based awards, vesting period	2 years
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based awards, Common stock reserved for issuance	23,165,393	22,997,639
Share based awards, maximum contractual term	10 years
Share based awards, vesting period	4 years
Weighted-average grant date fair value, options granted	$ 0.4
Total intrinsic value of options exercised	$ 100,000
Fair value of options vested	1,400,000
Unrecognised compensation cost	$ 3,000,000
Two Thousand Seventeen Stock Option and Grant Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based awards, Common stock reserved for issuance	25,956,535
Share based awards, maximum contractual term	10 years
Share based awards, shares available for future grant	1,167,685

Agreements with Horizon - Addit

Agreements with Horizon - Additional Information (Detail) - Horizon collaboration agreement [Member] - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Aug. 12, 2022	Oct. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement, transaction price	$ 55		$ 55	$ 55
Collaboration agreement, Aggregate amount of sales milestone		$ 75.1
Transaction price to be determined			55
Received amount from Horizon				32.5
Collaboration agreement revenue				$ 6.7
Amount retained			55
Collaboration agreement, contingent payment			75.1
Refund liability			55
Sales-based milestone [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration agreement, contingent payment			75.1
Collaboration agreement, contingent payment payable excess of cash received			$ 20.1

Agreements with Horizon - Summa

Agreements with Horizon - Summary of the Transaction Price Allocated to Each Performance Obligation (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Transaction Price	$ 55,000
AD phase 2 research services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Transaction Price	25,417
AA phase 2 research services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Transaction Price	18,265
Material right for the purchase of ADX-914
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Transaction Price	$ 11,318

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - Consulting and advisory agreements [Member] - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Related party transaction expense	$ 0	$ 87,000
Related party [Member]
Related Party Transaction [Line Items]
Due to related parties	$ 0	$ 0

Income Taxes - Schedule of Loss

Income Taxes - Schedule of Loss from Operations Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Pretax loss United States	$ (53,430)	$ (42,722)
Pretax loss Foreign	5	(25)
Pretax loss before income taxes	$ (53,425)	$ (42,747)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current:
Federal	$ 316	$ 0
State	1	0
Foreign	1	62
Total current	318	62
Deferred:
Federal	0	0
State	0	0
Foreign	0	0
Total deferred	0	0
Total income tax provision	$ 318	$ 62

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Benefit) Computed (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal income tax expense at statutory rate	21%	21%
State income taxes, net of federal benefit	5.90%	6.90%
Permanent differences	(1.20%)	(0.40%)
Convertible note revaluation	(1.80%)	0%
Research and development tax credits	3.10%	4.10%
Change in valuation allowance	(27.60%)	(31.60%)
Effective income tax rate	(0.60%)	0%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Taxes (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Federal net operating loss carryforwards	$ 13,412	$ 19,135
State net operating loss carryforwards	3,500	5,401
Contingent liability	14,876	0
Accruals and Reserves	818	659
Capitalized intangible assets	2,828	3,089
Tax credit carryforwards	5,762	4,745
Capitalized R&D expenditures	13,546	7,378
Lease liability	1,835	1,962
Stock compensation and other	544	318
Total gross deferred tax assets before valuation allowance	57,121	42,687
Less: Valuation allowance	(55,078)	(40,342)
Net deferred tax assets	2,043	2,345
Deferred tax liabilities:
Fixed assets	(339)	(483)
Right of use asset	(1,704)	(1,862)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Line Items]
Current and deferred income tax expense	$ 318,000	$ 62,000
Effective income tax rate	21%	21%
Net deferred tax assets	$ 57,121,000	$ 42,687,000
Valuation allowance period increase	14,700,000
Unrecognized tax benefits	$ 0
Tax credit carryforwards expiration year	2038
Unrecognized tax benefits, settlements		$ 1,400,000
Effective income tax rate	(0.60%)	0%
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 63,900,000
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 55,400,000
Net operating loss carryforwards, expiration year	2040
Research Tax Credit Carryforward [Member] | Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Research and development tax credit carryforwards	$ 4,300,000
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Research and development tax credit carryforwards	$ 1,800,000

Net Loss per Share - Summary of

Net Loss per Share - Summary of Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Series A convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	47,628,788	47,628,788
Series A-1 convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	6,500,000	6,500,000
Series B convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	54,689,627	54,689,627
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	23,165,393	22,997,639
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	377,899	166,371

Net Loss per Share - (Additiona

Net Loss per Share - (Additional Information) (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Earnings Per Share [Abstract]
Principal balance of convertible notes	$ 30

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent event [Member] - USD ($) shares in Millions, $ in Millions		1 Months Ended	2 Months Ended
	Mar. 26, 2024	Mar. 31, 2024	May 31, 2024
Subsequent Event [Line Items]
Net Proceeds of Advance Payment Drawn	$ 7		$ 7
Officers directors and other key members of the management [member] | 2024 Plan [Member]
Subsequent Event [Line Items]
Share based compensation by share based award options granted during the period shares		0.9