Tectonic Therapeutic (TECX) 10-Q 14 Aug 24 2024 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2024	Aug. 09, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Registrant Name	TECTONIC THERAPEUTIC, INC.
Entity Central Index Key	0001681087
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-38537
Entity Tax Identification Number	81-0710585
Entity Address, Address Line One	490 Arsenal Way
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Watertown
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02472
City Area Code	339
Local Phone Number	666-3320
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	TECX
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		14,734,479

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 185,124	$ 28,769
Prepaid expenses and other current assets	2,264	2,115
Total current assets	187,388	30,884
Property, equipment and improvements, net	2,639	3,122
Finance right-of-use assets, net	1,208	1,437
Operating right-of-use assets	2,075	2,669
Deferred offering costs	0	669
Restricted cash	587	587
Other assets	13	31
Total assets	193,910	39,399
Current liabilities:
Accounts payable	4,090	409
Accrued expenses and other current liabilities	20,009	8,141
SAFE liabilities	0	30,515
Operating lease liability - current portion	1,428	1,348
Finance lease liability - current portion	474	475
Total current liabilities	26,001	40,888
Operating lease liability - net of current portion	905	1,644
Finance lease liability - net of current portion	637	876
Total liabilities	27,543	43,408
Commitments and contingencies (Note 7)
Convertible preferred stock (Series A-1, A-2, A-3 and A-4), $0.0001 par value; 6,825,483 shares authorized as of December 31, 2023; 6,825,483 shares issued and outstanding as of December 31, 2023; aggregate liquidation preference of $87,459 as of December 31, 2023	0	80,627
Stockholders' Equity (Deficit):
Common stock	2	0
Additional paid-in capital	284,922	5,979
Accumulated other comprehensive loss	(61)	(11)
Accumulated deficit	(118,496)	(90,604)
Total stockholders' equity (deficit)	166,367	(84,636)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	$ 193,910	$ 39,399

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized	150,000,000	150,000,000
Common stock, issued	14,734,323	2,634,246
Common stock, outstanding	14,734,323	2,634,246
Convertible Preferred Stock [Member]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, authorized		6,825,483
Preferred stock, issued	6,825,483	6,825,483
Preferred stock, outstanding	6,825,483	6,825,483
Temporary Equity, Liquidation Preference		$ 87,459

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating expenses:
Research and development	$ 7,074	$ 8,766	$ 17,892	$ 21,751
General and administrative	4,347	1,865	6,497	3,411
Total operating expenses	11,421	10,631	24,389	25,162
Loss from operations	(11,421)	(10,631)	(24,389)	(25,162)
Other (expense) income, net:
Change in fair value of SAFE liabilities	(1,535)	0	(3,610)	0
Interest income	318	224	574	352
Interest expense	(28)	(40)	(59)	(82)
Other expense	(5)	(8)	(408)	(8)
Total other (expense) income, net	(1,250)	176	(3,503)	262
Net loss	$ (12,671)	$ (10,455)	$ (27,892)	$ (24,900)
Net loss per share attributable to common stockholders, basic	$ (4.34)	$ (8.51)	$ (12.97)	$ (20.6)
Net loss per share attributable to common stockholders, diluted	$ (4.34)	$ (8.51)	$ (12.97)	$ (20.6)
Weighted-average common shares outstanding, basic	2,919,872	1,228,778	2,150,160	1,208,447
Weighted-average common shares outstanding, diluted	2,919,872	1,228,778	2,150,160	1,208,447
Other comprehensive loss:
Foreign currency translation adjustment	$ (8)	$ 0	$ (50)	$ 0
Comprehensive loss	$ (12,679)	$ (10,455)	$ (27,942)	$ (24,900)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Convertible Preferred Stock [Member] Preferred Stock [Member]
Beginning balance at Dec. 31, 2022	$ (45,654)		$ 2,127		$ (47,781)	$ 80,627
Beginning balance (in shares) at Dec. 31, 2022		2,525,771				6,825,483
Retroactive application of reverse recapitalization		(1,175,948)				(3,177,808)
Adjusted balance, beginning of period	(45,654)		2,127		(47,781)	$ 80,627
Adjusted balance, beginning of period (in shares)		1,349,823				3,647,675
Exercise of stock options	1		1
Exercise of stock options (in shares)		686
Stock-based compensation expense	275		275
Net loss	(14,445)				(14,445)
Ending balance at Mar. 31, 2023	(59,823)		2,403		(62,226)	$ 80,627
Ending balance (in shares) at Mar. 31, 2023		1,350,509				3,647,675
Beginning balance at Dec. 31, 2022	(45,654)		2,127		(47,781)	$ 80,627
Beginning balance (in shares) at Dec. 31, 2022		2,525,771				6,825,483
Net loss	(24,900)
Ending balance at Jun. 30, 2023	(70,001)		2,680		(72,681)	$ 80,627
Ending balance (in shares) at Jun. 30, 2023		1,350,509				3,647,675
Beginning balance at Mar. 31, 2023	(59,823)		2,403		(62,226)	$ 80,627
Beginning balance (in shares) at Mar. 31, 2023		1,350,509				3,647,675
Stock-based compensation expense	277		277
Net loss	(10,455)				(10,455)
Ending balance at Jun. 30, 2023	(70,001)		2,680		(72,681)	$ 80,627
Ending balance (in shares) at Jun. 30, 2023		1,350,509				3,647,675
Beginning balance at Dec. 31, 2023	(84,636)		5,979	$ (11)	(90,604)	$ 80,627
Beginning balance (in shares) at Dec. 31, 2023		2,634,246				6,825,483
Retroactive application of reverse recapitalization		(1,226,452)				(3,177,808)
Adjusted balance, beginning of period	(84,636)		5,979	(11)	(90,604)	$ 80,627
Adjusted balance, beginning of period (in shares)		1,407,794				3,647,675
Exercise of stock options	4		4
Exercise of stock options (in shares)		1,535
Stock-based compensation expense	321		321
Foreign currency translation adjustment	(42)			(42)
Net loss	(15,221)				(15,221)
Ending balance at Mar. 31, 2024	(99,574)		6,304	(53)	(105,825)	$ 80,627
Ending balance (in shares) at Mar. 31, 2024		1,409,329				3,647,675
Beginning balance at Dec. 31, 2023	$ (84,636)		5,979	(11)	(90,604)	$ 80,627
Beginning balance (in shares) at Dec. 31, 2023		2,634,246				6,825,483
Exercise of stock options (in shares)	266,705
Net loss	$ (27,892)
Ending balance at Jun. 30, 2024	166,367	$ 2	284,922	(61)	(118,496)	$ 0
Ending balance (in shares) at Jun. 30, 2024		14,734,323				0
Beginning balance at Mar. 31, 2024	(99,574)		6,304	(53)	(105,825)	$ 80,627
Beginning balance (in shares) at Mar. 31, 2024		1,409,329				3,647,675
Exercise of stock options	644		644
Exercise of stock options (in shares)		265,165
Stock-based compensation expense	403		403
Conversion of convertible preferred stock into common stock in connection with the Merger	80,627	$ 80,627				$ (80,627)
Conversion of convertible preferred stock into common stock in connection with the Merger (in shares)		3,647,675				(3,647,675)
Issuance of common stock to related party investors upon redemption of the SAFEs	34,125		34,125
Issuance of common stock to related party investors upon redemption of the SAFEs (in shares)		1,470,839
Issuance of common stock under subscription agreement	94,601	$ 1	94,600
Issuance of common stock under subscription agreement (in shares)		4,163,606
Issuance of common stock upon the Merger	78,157	$ 1	78,156
Issuance of common stock upon the Merger (in shares)		3,777,709
Transaction cost in connection with the Merger	(9,937)		(9,937)
Foreign currency translation adjustment	(8)			(8)
Net loss	(12,671)				(12,671)
Ending balance at Jun. 30, 2024	$ 166,367	$ 2	$ 284,922	$ (61)	$ (118,496)	$ 0
Ending balance (in shares) at Jun. 30, 2024		14,734,323				0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
At the Market Facility [Member]
Net of offering costs	$ 2,000

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net loss	$ (27,892)	$ (24,900)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	713	734
Stock-based compensation expense	724	552
Non-cash lease expense	595	549
Change in fair value of SAFE liabilities	3,610	0
Change in fair value of SAFE liabilities		0
Change in operating assets and liabilities:
Prepaid expenses and other current assets	(252)	(479)
Other non-current assets	422	(14)
Accounts payable	(70)	1,706
Accrued expenses and other current liabilities	153	1,645
Operating lease liabilities	(658)	(336)
Net cash used in operating activities	(22,655)	(20,543)
Cash flows from investing activities:
Purchase of property, equipment and improvements	0	(222)
Net cash used in investing activities	0	(222)
Cash flows from financing activities:
Proceeds from the Subscription Agreement, net of offering costs of $2,000	94,600	0
Cash acquired in connection with the Merger	85,230	0
Payment for Merger transaction costs	(1,168)	0
Proceeds from exercise of common stock options	648	1
Repayment of finance lease obligations	(240)	(270)
Net cash provided by (used in) financing activities	179,070	(269)
Effect of exchange rate changes on cash and cash equivalents	(60)	0
Net increase (decrease) in cash and cash equivalents and restricted cash	156,355	(21,034)
Cash and cash equivalents and restricted cash as of beginning of period	29,356	36,553
Cash and cash equivalents and restricted cash as of end of period	185,711	15,519
Components of cash, cash equivalents and restricted cash:
Cash and cash equivalents	185,124	14,932
Restricted cash	587	587
Total cash, cash equivalents and restricted cash	185,711	15,519
Supplemental disclosure of non-cash financing activities:
Merger transaction costs included in accounts payable and accrued expenses and other current liabilities	8,769	0
Conversion of SAFEs to Common Stock	34,125	0
Conversion Of Convertible Preferred Stock To Common Stock	80,627	0
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 59	$ 82

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Statement of Cash Flows [Abstract]
Offering Cost	$ 2,000

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. DESCRIPTION OF BUSINESS Business Tectonic Therapeutic, Inc. (formerly AVROBIO, Inc.) (the “Company” or “Tectonic”) is a clinical-stage biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of G-protein Reverse Merger and Pre-Merger On June 20, 2024, the Company completed its previously announced merger transaction in accordance with the terms of the Agreement and Plan of Merger and Reorganization, dated as of January 30, 2024 (the “Merger Agreement”) with AVROBIO, Inc. (“AVROBIO”), pursuant to which Alpine Merger Subsidiary, Inc., a wholly owned subsidiary of AVROBIO, merged with and into the entity formerly known as Tectonic Therapeutic, Inc., now known as Tectonic Operating Company, Inc. (“Legacy Tectonic”), with Legacy Tectonic continuing as a wholly owned subsidiary of the surviving corporation of AVROBIO (the “Merger”). The Merger is being accounted for as a reverse recapitalization in accordance with generally accepted accounting principles in the United States of America (“GAAP”), with AVROBIO treated as the acquired company for financial reporting purposes, and Legacy Tectonic treated as the accounting acquirer. Upon the closing of the Merger, each outstanding share of Legacy Tectonic’s as defined in the Merger Agreement, after giving effect to the 1-for-12 reverse stock split of AVROBIO common stock that was effected on June 20, 2024. The exchange ratio was retroactively applied to all outstanding common shares, convertible preferred shares, stock options and restricted stock. Each outstanding and unexercised option to purchase shares of Legacy Tectonic’s common stock immediately prior to closing was assumed by AVROBIO and was converted into an option to purchase shares of AVROBIO common stock, with necessary adjustments to the number of shares and exercise price to reflect the Exchange Ratio. All of Legacy Tectonic’s restricted common stock outstanding and unvested immediately prior to the closing that was assumed by AVROBIO in the Merger remains unvested to the same extent and is subject to the same repurchase option, risk of forfeiture or other condition under any applicable restricted stock purchase agreement. Legacy Tectonic stockholders received approximately shares of AVROBIO common stock in connection with the Merger, including shares of AVROBIO common stock subject to vesting terms, based on the number of shares of Legacy Tectonic common stock outstanding immediately prior to the Merger, including restricted stock, the number of shares of common stock issued to investors participating in the Subscription Agreements (as defined below) and SAFEs, and Legacy Tectonic convertible preferred stock outstanding immediately prior to the Merger, which was converted into shares of Legacy Tectonic common stock on a one-for-one basis In connection with the Merger, the Company and its designated rights agent entered into a contingent value rights agreement (the “CVR Agreement”). Pursuant to the CVR Agreement, each holder of AVROBIO common stock immediately prior to the closing received a contractual contingent value right (“CVR”) subject to and in accordance with the terms and conditions of the CVR Agreement, representing the contractual right to receive a pro rata portion of any net proceeds, if any, as a resulting from a disposition of certain AVROBIO intellectual property (including a license of AVROBIO’s pre-closing assets as defined in the CVR Agreement) after the closing and prior to the 18-month anniversary c a 10-year period c proceeds have been received under the CVR Agreement. As of June 30, 2024 there is no liability recorded in connection with the CVR Agreement. Concurrently with the closing of the Merger, certain investors of Legacy Tectonic Legacy Tectonic Subscription Agreement Legacy Tectonic Risks and Uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical The Company’s proprietary GEODe ™ Liquidity and Going Concern As of June 30, 2024, the Company had an accumulated deficit of $118.5 million and has incurred losses and negative cash flows from operations since inception, including a net loss of $12.7 million and $27.9 million for the three and six months ended June 30, 2024, respectively. To date, the Company has financed its operations primarily through the issuance of common stock, convertible preferred stock, convertible promissory notes and Simple Agreements for Future Equity (“SAFEs”). The Company has devoted substantially all of its financial resources and efforts to business planning, conducting research and development, recruiting management and technical staff, and raising capital. Management expects that the Company’s operating losses and negative cash flows will continue for the foreseeable future as it continues to develop its product candidates. As the Company continues to develop its proprietary platform and potential product candidates, it will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. It may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital to fund its operations. Management believes that its current cash on hand, which includes the proceeds related to the Merger and Subscription Agreements, is sufficient to fund the Company’s planned operations for at least one year from the date of issuance of these unaudited condensed consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES During the six months ended June 30, 2024, there were no significant changes to the Company’s significant accounting policies as described in the Company’s audited consolidated financial statements as of and for the years ended December 31, 2023 and 2022. Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in conformity with GAAP and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to applicable guidance is meant to refer to GAAP, as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair presentation of its financial position and its results of operations, changes in convertible preferred stock and stockholders’ equity (deficit) and cash flows. The information as of December 31, 2023 included in the unaudited interim condensed consolidated balance sheets was derived from audited annual consolidated financial statements but does not contain all of the footnote disclosures from the audited annual consolidated financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of and Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting periods. Significant items subject to such estimates and assumptions include the contract research accruals, stock-based compensation expense, the fair value of the Company’s common stock, the income tax valuation allowance, and the fair value determination of the SAFEs. Management’s estimates are based on historical experience and various other assumptions that it believes are reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB, or other standard setting bodies and are adopted by the Company as of the specified effective dates. Unless otherwise Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting 2023-07”), 2023-07, 2023-07 2023-07 2023-07 statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes 2023-09”), 2023-09, 2023-09 2023-09

Merger

Merger	6 Months Ended
	Jun. 30, 2024
Merger [Abstract]
Merger	3. MERGER As described in Note 1, the Company completed its previously announced Merger with AVROBIO on June 20, 2024. The Merger was accounted for as a reverse recapitalization in accordance with GAAP with Legacy Tectonic as the accounting acquirer of AVROBIO. At the effective time of the Merger, substantially all the assets of AVROBIO consisted of cash and cash equivalents, as well as other nominal non-operating As part of the recapitalization, Legacy Tectonic obtained the assets and liabilities listed below: Cash and cash equivalents $ 85,230 Prepaid expenses and other current assets 319 Accounts payable (1,988 ) Accrued expenses and other current liabilities (5,405 ) Net assets acquired $ 78,156 The Company incurred transaction costs of $9.9 million, of which $8.2 million was recorded within accrued expenses and other current liabilities on the condensed consolidated balance sheet, $0.6 million was recorded within accounts payable on the condensed consolidated balance sheet and $1.2 million was paid in cash as of June 30, 2024. This amount was recorded as a reduction to additional paid-in With respect to the CVRs issued in connection with the Merger, the Company believes that any receipt of payments resulting from an AVROBIO disposition of AVROBIO’s pre-closing assets described in the CVR Agreement are highly susceptible to factors outside the Company’s influence that are not expected to be resolved within the timeline outlined in the CVR Agreement, if at all. In particular, these amounts are primarily influenced by the actions and judgments of third parties and the buyers of such assets and are based on the buyers of such assets progressing the specific platform and intellectual property and early stage of research and development programs. If the Company were to record a receivable for such contingent payments, it would also record a corresponding liability. As of June receivables or liabilities were recorded on the condensed consolidated balance sheet relating to such contingent payments.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. FAIR VALUE MEASUREMENTS The following tables present information about financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): June 30, 2024 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 100,442 $ —  $ —  $ 100,442 $ 100,442 $ —  $ —  $ 100,442 December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 27,278 $ —  $ —  $ 27,278 Liabilities: $ 27,278 $ —  $ —  $ 27,278 SAFE liabilities $ —  $ —  $ 30,515 $ 30,515 $ —  $ —  $ 30,515 $ 30,515 As of June 30, 2024 and December 31, 2023, the Company’s cash equivalents, which were invested in money market funds, were valued based on Level 1 inputs. There were no transfers between the Level 1, Level 2 or Level 3 categories during the six months ended June 30, 2024 and 2023. SAFE Liabilities From October through December 2023, Legacy Tectonic million. Prior to redemption, the SAFE liabilities were valued using a probability weighted scenario analysis and discount rates derived by application of the build-up method to reflect the cost of equity. The valuation model required a variety of inputs, including the probability of occurrence of events that would trigger conversion or redemption of the SAFEs, the expected timing of such events, and a discount rate. Upon the closing of the Merger, the principal balance of the SAFEs was automatically redeemed for 2,752,216 shares of Legacy per share immediately prior to the Merger closing. As such the valuation inputs utilized to adjust the SAFE liability to fair value upon the closing of the Merger At closing, shares of Legacy Tectonic common stock issued pursuant to the redemption of Legacy Tectonic SAFEs were converted into The following table presents activity for the SAFE liabilities that were measured at fair value using significant unobservable Level 3 inputs during the six months ended June 30, 2024 and the year ended December 31, 2023 (in thousands): SAFE Liabilities Balance as of January 1, 2023 $ —  Initial fair value recognition 31,515 Loss on issuance 255 Fair value adjustments (1,255 ) Balance as of December 31, 2023 30,515 Fair value adjustments 3,610 Conversion (34,125 ) Balance as of June 30, 2024 $ —

Property, Equipment and Improve

Property, Equipment and Improvements, Net	6 Months Ended
	Jun. 30, 2024
Property, Plant and Equipment [Abstract]
Property, Equipment and Improvements, Net	5. PROPERTY, EQUIPMENT AND IMPROVEMENTS, NET Property, equipment and improvements, net is comprised of the following (in thousands): June 30, December 31, Laboratory equipment $ 4,554 $ 4,510 Furniture and office equipment 244 244 Computer equipment 198 161 Construction in progress —  38 Leasehold improvements 25 25 5,021 4,978 Less: accumulated depreciation (2,382 ) (1,856 ) Property and equipment, net $ 2,639 $ 3,122 Depreciation expense was $0.3 million and $0.2 million during the three months ended June 30, 2024 and 2023, respectively, and $0.5 million during each of the six months ended June 30, 2024 and 2023, which was recorded as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 5 $ 4 $ 9 $ 8 Research and development 259 242 517 468 $ 264 $ 246 $ 526 $ 476

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities is comprised of the following (in thousands): June 30, 2024 December 31, 2023 Accrued Tectonic transaction costs $ 8,215 $ —  Accrued AVROBIO transaction costs 2,821 —  Employee compensation related costs 2,755 2,840 A ccrued offering costs related to the Subscription Agreement 2,000 —  Accrued professional fees 1,607 1,798 Accrued contract research organization fees 985 2,298 Accrued contract development and manufacturing organization fees 649 660 Accrued office and laboratory costs 91 211 Other current liabilities 886 334 $ 20,009 $ 8,141

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. COMMITMENTS AND CONTINGENCIES Leases The Company’s commitments under its operating and finance leases are described in Note 8. Harvard Agreement In July 2020, Legacy Tectonic entered into an agreement with the President and Fellows of Harvard College (“Harvard”), for an option fee in the low five digits, whereby Harvard granted Legacy Tectonic an exclusive option to negotiate a worldwide, exclusive, royalty-bearing license under Harvard’s interest in the patent rights covering certain technology that was developed by Harvard. In October 2021, Legacy Tectonic exercised the option and on February 10, 2022, entered into a license agreement (“License Agreement”) with Harvard to conduct research and development activities using certain materials, technology and patent rights owned by Harvard, with the intent to develop, obtain regulatory approval for, and commercialize products. The License Agreement will remain in effect until the expiration of the last valid claim within the patent rights covering a product developed under the License Agreement or the termination of the License Agreement. Management concluded that the acquisition of patents and materials received under the License Agreement represents an asset acquisition of an in-progress As consideration for the License Agreement, Legacy Tectonic non-refundable The Company also will be responsible for payment of (1) annual maintenance fees ranging from the low five digits to the low six digits during the term of the License Agreement (through the first commercial sale of a royalty-bearing product); (2) royalty payments as a percentage in the low single digits of the annual net sales that the Company generates from products that utilize the license technology (“Licensed Products”) and royalty payments as a percentage in the low single digits of the annual net sales that the Company generates from know-how (“Know-How 10-20% non-royalty know-how country-by-country product-by-product The royalty term from sales of Know-How Know-How the Company paid less than $ Alloy Therapeutics License Agreement On November 29, 2021, Legacy Tectonic non-refundable non-creditable Legacy Tectonic During the three months ended June 30, 2024 and 2023, the Company paid $ Adimab Agreement On May 1, 2023, Legacy Tectonic entered into a discovery agreement with Adimab, LLC (“Adimab”), an antibody discovery company, whereby Legacy Tectonic and Adimab are collaborating on human antibody discovery in accordance with an agreed upon research program. Legacy Tectonic paid an upfront technology access fee totaling The Company also will be responsible for payment of (1) quarterly funding equal to 100% of the actual full-time employee (“FTE”) expended by Adimab in the performance of its obligations in accordance with the agreed upon research program at an annual rate of $0.4 million per FTE (subject to annual consumer price index increases) per the agreement, (2) delivery fees equal to $0.1 million upon both Adimab’s initial delivery of sequences or physical materials and completion pursuant to the research program (initial and completion fees payable once per target for a total of up to $0.4 million), (3) a non-creditable, non-refundable of discovery delivery fees in accounts payable. During the three months ended June 30, 2024 and 2023, the Company paid $0.2 million and less than $0.1 million to Adimab, respectively. During the six months ended June 30, 2024 and 2023, the Company paid $0.3 million and less than $0.1 million to Adimab, respectively. Indemnification Agreements In accordance with the Company’s amended and restated certificate of incorporation (“ARCOI”) and certain indemnification agreements, the Company indemnifies certain officers and directors for specified events or occurrences, subject to certain limits, in which the officer or director is or was serving at the Company’s request in such capacity. The Company enters into certain types of contracts that contingently requires it to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company’s bylaws, under which it must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship with the Company, (ii) contracts under which it must indemnify directors and certain officers and consultants for liabilities arising out of their relationship, and (iii) procurement, service or license agreements under which the Company may be required to indemnify vendors, service providers or licensees for certain claims, including claims that may be brought against them arising from the Company’s acts or omissions with respect to the its products, technology, intellectual property or services. From time to time, the Company may receive indemnification claims under these contracts in the normal course of business. In the event that one or more of these matters were to result in a claim against the Company, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on future business, operating results or financial condition. It is not possible to estimate the maximum amount potentially payable under these contracts since there is no history of prior indemnification claims and the unique facts and circumstances involved in each particular claim will be determinative. As of June 30, 2024 and December 31, 2023, the Company did not have any liabilities or other commitments related to indemnification claims. Litigation In the normal course of operations, the Company may become involved in various legal proceedings. As of June 30, 2024 and December 31, 2023, the Company has not recorded accruals for probable losses related to any existing or pending litigation as the Company’s management has determined that there are no matters where a potential loss is probable and reasonably estimable. The Company does not believe that any existing or pending claims would have a material impact on the Company’s condensed consolidated financial statements.

Leases

Leases	6 Months Ended
	Jun. 30, 2024
Leases [Abstract]
Leases	8. LEASES Legacy Tectonic from approximately to approximately years. These In November 2020, Legacy Tectonic non-lease The following table sets forth information about lease costs for the three and six months ended June 30, 2024 and 2023 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Finance lease cost Amortization of ROU assets $ 115 $ 124 $ 230 $ 258 Interest on lease liabilities 28 39 59 81 Operating lease cost 351 351 702 702 Short-term lease cost 185 198 360 348 Variable lease cost 198 195 448 401 Total lease costs $ 877 $ 907 $ 1,799 $ 1,790 The following table sets forth information about the Company’s leases for the six months ended June 30, 2024 and 2023 (in thousands): Six Months Ended June 30, 2024 2023 Cash paid for amounts included in the measurement of lease liabilities Finance leases - financing cash flows $ 240 $ 270 Finance leases - operating cash flows 59 81 Operating leases - operating cash flows 765 489 Weighted-average remaining lease terms (in years) Finance leases 2.75 3.73 Operating leases 1.59 2.59 Weighted-average discount rate Finance leases 9.69 % 9.58 % Operating leases 8.25 % 8.25 % The following table presents the maturity of the Company’s finance and operating lease liabilities for as of ended June 30, 2024 (in thousands): Year ended December 31, Finance Leases Operating Leases 2024 (remaining) $ 284 $ 769 2025 552 1,580 2026 363 132 2027 44 —  2028 —  —  Thereafter —  —  Total lease payments 1,243 2,481 Less: interest (132 ) (148 ) Total lease liabilities $ 1,111 $ 2,333

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Stockholders' Equity	9. STOCKHOLDERS’ EQUITY Convertible Preferred Stock Prior to the conversion upon the closing of the Merger, Legacy Tectonic issued Series A-1, Prior to the completion of the Merger, Legacy Tectonic classified the Preferred Stock outside of permanent equity as the shares had redemption features that were not entirely within the control of Legacy Tectonic. Upon the closing of the Merger, all outstanding shares of the Preferred Stock were converted into shares of the Preferred Stock were outstanding as of June 30, 2024. Preferred Stock Subsequent to consummation of the Merger, the Company authorized the issuance of shares of new undesignated preferred stock, however such shares were issued or outstanding as of June 30, 2024. Common Stock As of June 30, 2024 and as a result of the Merger, the Company’s ARCOI authorized the Company to issue shares of voting common stock of $ par value common stock, of which shares were issued and outstanding . . In addition, holders of voting common stock are entitled to receive dividends, if and when declared by the Company’s Board of Directors. As of June 30, 2024, dividends had been declared. The Company has included in issued and outstanding common stock shares of restricted common stock granted by the Company. As of June 30, 2024, there were 14,734,323 shares of stock relate to shares of restricted common stock (see Note 10).

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	1 0 STOCK-BASED COMPENSATION 2019 Equity Incentive Plan The non-employee 2024 Equity Incentive Plan On June 20, 2024, the Company adopted the 2024 Equity Incentive Plan (the “2024 Plan”) which became effective upon completion of the Merger. The 2024 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of awards to employees, consultants, and non-employee The 2024 Plan initially provided for the issuance of up to 1,938,799 shares of common stock (the “Initial Share Reserve”). Subject to any other adjustments as defined in the 2024 Plan, such aggregate number of shares of common stock will automatically increase on January 1st of each year for a period of ten years commencing on January 1, 2025 and ending on (and including) January 1, 2034, in an amount equal to 5% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase; provided, however that the board of directors may act prior to January 1st of a given year to provide that the increase for such year will be a lesser number of shares of common stock. The aggregate maximum number of shares of common stock that may be issued pursuant to the exercise of incentive stock options is three multiplied by the Initial Share Reserve. As of June 30, 2024, there were 1,063,999 shares available for issuance under the 2024 Plan. 2024 Employee Stock Purchase Plan On June 20, 2024, the Company adopted the 2024 Employee Stock Purchase Plan (the “2024 ESPP”), which became effective upon completion of the Merger. The maximum number of shares of common stock that may be issued under the 2024 ESPP will not exceed 147,343 shares (the “Initial ESPP Share Reserve”), plus the number of shares of common stock that are automatically added on January 1st of each year for a period of up to ten years commencing on January 1, 2025 and ending on (and including) January 1, 2034, in an amount equal to the lesser of (x) 1% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase and (y) a number of shares equal to three times the Initial ESPP Share Reserve. Notwithstanding the foregoing, the B D The option activity below reflects the reverse stock split and retroactive application of the exchange ratio as discussed in Note 1. A summary of the stock option activity for the six months ended June 30, 2024 is as follows (in thousands except share and per share amounts): Number of Shares Weighted- Weighted-Average Aggregate Balance as of January 1, 2024 1,002,485 $ 3.11 8.2 $ 2,276 Granted 874,800 16.80 Exercised (266,705 ) 2.44 $ 3,743 Forfeited and expired (31,922 ) 2.71 Options assumed from AVROBIO upon Merger closing 365,428 89.92 Balance as of June 30, 2024 1,944,086 $ 25.68 7.5 $ 9,830 Options vested and exercisable as of June 30, 2024 683,184 $ 49.36 3.8 $ 4,987 Options vested and expected to vest as of June 30, 2024 1,944,086 $ 25.68 7.5 $ 9,830 The weighted-average grant-date fair value of options granted during the six months ended June 30, 2024 and 2023 was $13.95 and $2.51 per share, respectively. The total intrinsic value of options exercised during the three months ended June 30, 2024 and 2023 was $3.7 million and $0, respectively, and was $3.7 million and less than million Cash received from option exercises was $0.6 million for the three and six months ended June 30, 2024 and $0 and less tha n $0.1 million for the three and six months ended June 30, 2023, respectively . The fair values of the options granted in the six months ended June 30, 2023 were estimated based on the Black-Scholes-Merton option pricing model, using the following assumptions: Six Months Ended June 30, 2024 2023 Fair value per share of underlying common stock $16.80 $2.98 Expected term (in years) 6.25 5.93 Expected volatility 104.00% 111.05% - 111.21% Risk-free interest rate 4.26% 3.65% Expected dividend yield 0% 0% Restricted Common Stock Since 2019, Legacy Tectonic The following table summarizes restricted stock activity: Number of Shares Unvested restricted common stock as of January 1, 2024 18,968 Granted —  Early exercise of options 6,859 Vested (14,380 ) Forfeited —  Unvested restricted common stock as of June 30, 2024 11,447 The weighted-average grant date fair value of unvested restricted common stock and restricted common stock vested and forfeited for the six months ended June 30, 2024 and 2023 was immaterial. Stock-Based Compensation Expense The Company recorded stock-based compensation expense regarding its employees and nonemployees as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 228 $ 175 $ 421 $ 349 Research and development 175 102 303 203 $ 403 $ 277 $ 724 $ 552 The Company records compensation expense for options with service based vesting conditions on a straight-line basis over the vesting period. As of June 30, 2024, total compensation cost not yet recognized related to unvested stock options was $

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	1 1 INCOME TAXES During the three and six months ended June 30, 2024 and 2023, the Company recorded no income tax provision or benefit. The Company has evaluated the positive and negative evidence bearing upon its ability to realize its deferred tax assets, which primarily consist of net operating loss carryforwards. The Company has considered its history of cumulative net losses, estimated future taxable income and prudent and feasible tax planning strategies and has concluded that it is more likely than not that the Company will not realize the benefits of its deferred tax assets. As a result, as of June 30, 2024, the Company has maintained a full valuation allowance against its net deferred tax assets.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	1 2 NET LOSS PER SHARE Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ (12,671) $ (10,455 ) $ (27,892 ) $ (24,900 ) Denominator: Weighted-average common shares outstanding, basic and diluted 2,919,872 1,228,778 2,150,160 1,208,447 Net loss per share attributable to common stockholders, basic and diluted $ (4.34 ) $ (8.51 ) $ (12.97 ) $ (20.60 ) The Company’s potential dilutive securities 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. For the three and six months ended June 30, 2024 and 2023, the Company excluded the following potential common shares from the computation of diluted net loss per share attributable to common stockholders for the period because including them would have had an anti-dilutive effect: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Convertible preferred stock (as converted to common stock) —  3,647,675 —  3,647,675 Stock options to purchase common stock 1,944,086 852,667 1,944,086 852,667 Unvested restricted common stock 11,447 36,504 11,447 36,504 1,955,533 4,536,846 1,955,533 4,536,846

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	13. RELATED PARTY TRANSACTIONS Scientific Advisory Board Member One of the Company’s co-founders 0.1 million during the six months ended June 30, 2024 and 2023 for advisory services provided. There was less than $0.1 million and $0 due to this related party as of June 30, 2024 and December 31, 2023. License Agreement Harvard meets the criteria of a related party resulting from the Company’s co-founders’ co-founders co-founder For the six months ended June 30, 2024 and 2023, the Company paid Harvard $0.1 million and $0.2 million in cash considerations, respectively (see Note 7). Accounts payable to Harvard amounted to less than $ million as of June 30, 2024 and December 31, 2023, respectively. SAFE Agreements From October through December 2023, Legacy Tectonic million representing the purchase amount. All investors were considered related parties of the Company. The SAFE agreements had no maturity date, bore no interest, and were redeemable by Legacy Tectonic upon the occurrence of a triggering event, including the Merger which qualified as a public listing transaction under the SAFE agreements. As discussed in Note 4, the SAFEs were redeemed for shares of Legacy Tectonic common stock in connection with the closing of the Merger.

Employee Benefit Plan

Employee Benefit Plan	6 Months Ended
	Jun. 30, 2024
Defined Contribution Plan [Abstract]
Employee Benefit Plan	14. EMPLOYEE BENEFIT PLAN The Company has a 401(k) retirement plan (the “Plan”) that covers eligible U.S. employees. Eligible employees may elect to contribute up to the maximum limits, as set by the Internal Revenue Service, of their eligible compensation. The Company’s funding policy is to contribute 3% (“Nonelective Contribution”) of employees’ eligible pay to the Plan. Highly compensated employees (as defined by the Plan) are not eligible to receive the Nonelective Contribution. The Company’s contributions were $0.1 million during each of the three and six months ended June 30, 2024 and 2023 and were recorded as follows: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 10 $ 5 $ 16 $ 12 Research and development 70 47 114 116 $ 80 $ 52 $ 130 $ 128

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed consolidated financial statements have been prepared in conformity with GAAP and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to applicable guidance is meant to refer to GAAP, as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). In the opinion of the Company, the accompanying unaudited condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair presentation of its financial position and its results of operations, changes in convertible preferred stock and stockholders’ equity (deficit) and cash flows. The information as of December 31, 2023 included in the unaudited interim condensed consolidated balance sheets was derived from audited annual consolidated financial statements but does not contain all of the footnote disclosures from the audited annual consolidated financial statements. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of and
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting periods. Significant items subject to such estimates and assumptions include the contract research accruals, stock-based compensation expense, the fair value of the Company’s common stock, the income tax valuation allowance, and the fair value determination of the SAFEs. Management’s estimates are based on historical experience and various other assumptions that it believes are reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB, or other standard setting bodies and are adopted by the Company as of the specified effective dates. Unless otherwise
Recently issued accounting pronouncements not yet adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting 2023-07”), 2023-07, 2023-07 2023-07 2023-07 statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes 2023-09”), 2023-09, 2023-09 2023-09

Merger (Tables)

Merger (Tables)	6 Months Ended
	Jun. 30, 2024
Business Combinations [Abstract]
Summary Of The Company Obtain The Assets And Liabilities	As part of the recapitalization, Legacy Tectonic obtained the assets and liabilities listed below: Cash and cash equivalents $ 85,230 Prepaid expenses and other current assets 319 Accounts payable (1,988 ) Accrued expenses and other current liabilities (5,405 ) Net assets acquired $ 78,156

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present information about financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values (in thousands): June 30, 2024 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 100,442 $ —  $ —  $ 100,442 $ 100,442 $ —  $ —  $ 100,442 December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 27,278 $ —  $ —  $ 27,278 Liabilities: $ 27,278 $ —  $ —  $ 27,278 SAFE liabilities $ —  $ —  $ 30,515 $ 30,515 $ —  $ —  $ 30,515 $ 30,515
Summary of Activity for the Safe Liabilities that were Measured at Fair Value	The following table presents activity for the SAFE liabilities that were measured at fair value using significant unobservable Level 3 inputs during the six months ended June 30, 2024 and the year ended December 31, 2023 (in thousands): SAFE Liabilities Balance as of January 1, 2023 $ —  Initial fair value recognition 31,515 Loss on issuance 255 Fair value adjustments (1,255 ) Balance as of December 31, 2023 30,515 Fair value adjustments 3,610 Conversion (34,125 ) Balance as of June 30, 2024 $ —

Property, Equipment and Impro_2

Property, Equipment and Improvements, Net (Tables)	6 Months Ended
	Jun. 30, 2024
Property, Plant and Equipment [Abstract]
Summary of Property Equipment and Improvements Net	Property, equipment and improvements, net is comprised of the following (in thousands): June 30, December 31, Laboratory equipment $ 4,554 $ 4,510 Furniture and office equipment 244 244 Computer equipment 198 161 Construction in progress —  38 Leasehold improvements 25 25 5,021 4,978 Less: accumulated depreciation (2,382 ) (1,856 ) Property and equipment, net $ 2,639 $ 3,122
Summary of Depreciation Expenses	Depreciation expense was $0.3 million and $0.2 million during the three months ended June 30, 2024 and 2023, respectively, and $0.5 million during each of the six months ended June 30, 2024 and 2023, which was recorded as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 5 $ 4 $ 9 $ 8 Research and development 259 242 517 468 $ 264 $ 246 $ 526 $ 476

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities is comprised of the following (in thousands): June 30, 2024 December 31, 2023 Accrued Tectonic transaction costs $ 8,215 $ —  Accrued AVROBIO transaction costs 2,821 —  Employee compensation related costs 2,755 2,840 A ccrued offering costs related to the Subscription Agreement 2,000 —  Accrued professional fees 1,607 1,798 Accrued contract research organization fees 985 2,298 Accrued contract development and manufacturing organization fees 649 660 Accrued office and laboratory costs 91 211 Other current liabilities 886 334 $ 20,009 $ 8,141

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2024
Leases [Abstract]
Schedule of effect of lease costs in the company's consolidated statement of operations and comprehensive loss	The following table sets forth information about lease costs for the three and six months ended June 30, 2024 and 2023 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Finance lease cost Amortization of ROU assets $ 115 $ 124 $ 230 $ 258 Interest on lease liabilities 28 39 59 81 Operating lease cost 351 351 702 702 Short-term lease cost 185 198 360 348 Variable lease cost 198 195 448 401 Total lease costs $ 877 $ 907 $ 1,799 $ 1,790
Schedule of information about the company's leases	The following table sets forth information about the Company’s leases for the six months ended June 30, 2024 and 2023 (in thousands): Six Months Ended June 30, 2024 2023 Cash paid for amounts included in the measurement of lease liabilities Finance leases - financing cash flows $ 240 $ 270 Finance leases - operating cash flows 59 81 Operating leases - operating cash flows 765 489 Weighted-average remaining lease terms (in years) Finance leases 2.75 3.73 Operating leases 1.59 2.59 Weighted-average discount rate Finance leases 9.69 % 9.58 % Operating leases 8.25 % 8.25 %
Schedule in tabular form of maturity of operating and finance leases	The following table presents the maturity of the Company’s finance and operating lease liabilities for as of ended June 30, 2024 (in thousands): Year ended December 31, Finance Leases Operating Leases 2024 (remaining) $ 284 $ 769 2025 552 1,580 2026 363 132 2027 44 —  2028 —  —  Thereafter —  —  Total lease payments 1,243 2,481 Less: interest (132 ) (148 ) Total lease liabilities $ 1,111 $ 2,333

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of The Stock Option Activity	A summary of the stock option activity for the six months ended June 30, 2024 is as follows (in thousands except share and per share amounts): Number of Shares Weighted- Weighted-Average Aggregate Balance as of January 1, 2024 1,002,485 $ 3.11 8.2 $ 2,276 Granted 874,800 16.80 Exercised (266,705 ) 2.44 $ 3,743 Forfeited and expired (31,922 ) 2.71 Options assumed from AVROBIO upon Merger closing 365,428 89.92 Balance as of June 30, 2024 1,944,086 $ 25.68 7.5 $ 9,830 Options vested and exercisable as of June 30, 2024 683,184 $ 49.36 3.8 $ 4,987 Options vested and expected to vest as of June 30, 2024 1,944,086 $ 25.68 7.5 $ 9,830
Summary of Fair Values of the Options Granted	The fair values of the options granted in the six months ended June 30, 2023 were estimated based on the Black-Scholes-Merton option pricing model, using the following assumptions: Six Months Ended June 30, 2024 2023 Fair value per share of underlying common stock $16.80 $2.98 Expected term (in years) 6.25 5.93 Expected volatility 104.00% 111.05% - 111.21% Risk-free interest rate 4.26% 3.65% Expected dividend yield 0% 0%
Summary of Restricted Stock Activity	The following table summarizes restricted stock activity: Number of Shares Unvested restricted common stock as of January 1, 2024 18,968 Granted —  Early exercise of options 6,859 Vested (14,380 ) Forfeited —  Unvested restricted common stock as of June 30, 2024 11,447
Summary of Stock Based Compensation Expense Regarding its Employees and Nonemployees	The Company recorded stock-based compensation expense regarding its employees and nonemployees as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 228 $ 175 $ 421 $ 349 Research and development 175 102 303 203 $ 403 $ 277 $ 724 $ 552

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Summary of Basic and Diluted Earnings Per Share	Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ (12,671) $ (10,455 ) $ (27,892 ) $ (24,900 ) Denominator: Weighted-average common shares outstanding, basic and diluted 2,919,872 1,228,778 2,150,160 1,208,447 Net loss per share attributable to common stockholders, basic and diluted $ (4.34 ) $ (8.51 ) $ (12.97 ) $ (20.60 )
Summary of Diluted Net Loss Per Share Attributable to Common Stockholders	the following potential common shares from the computation of diluted net loss per share attributable to common stockholders for the period because including them would have had an anti-dilutive effect: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Convertible preferred stock (as converted to common stock) —  3,647,675 —  3,647,675 Stock options to purchase common stock 1,944,086 852,667 1,944,086 852,667 Unvested restricted common stock 11,447 36,504 11,447 36,504 1,955,533 4,536,846 1,955,533 4,536,846

Employee Benefit Plan (Tables)

Employee Benefit Plan (Tables)	6 Months Ended
	Jun. 30, 2024
Defined Contribution Plan [Abstract]
Summary of defined contribution plan	Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 General and administrative $ 10 $ 5 $ 16 $ 12 Research and development 70 47 114 116 $ 80 $ 52 $ 130 $ 128

Description of Business - Addit

Description of Business - Additional Information (Detail) - USD ($)		3 Months Ended				6 Months Ended
	Jan. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Nature Of Operations [Line Items]
Retained earnings (accumulated deficit)		$ (118,496,000)				$ (118,496,000)		$ (90,604,000)
Net loss		(12,671,000)	$ (15,221,000)	$ (10,455,000)	$ (14,445,000)	(27,892,000)	$ (24,900,000)
Proceeds received pursuant to agreement						$ 0
Avorbio Common Stock [Member]
Nature Of Operations [Line Items]
Stock issued during the period shares new issues converted pursuant to reverse recapitalization						4,163,606
AVROBIO [Member]
Nature Of Operations [Line Items]
Business combination, contingent consideration, liability, current		0				$ 0
AVRO Avrobio Common Stock [Member]
Nature Of Operations [Line Items]
Conversion of stock shares percentage						0.53%
Stock issued during the period shares reverse recapitalization						10,956,614
Stock shares issued during the period subject to reverse recapitalization						6,901
Subscription Agreement [Member]
Nature Of Operations [Line Items]
Stock issued during the period shares new issues	7,790,889
Sale of stock issue price per share	$ 12.4
Proceeds from the issuance of common stock	$ 96,600,000
CVR Agreement [Member]
Nature Of Operations [Line Items]
Business combination, acquired receivables, gross contractual amount		400,000				$ 400,000
Liability recorded		$ 0				$ 0
AVROBIO, Inc [Member]
Nature Of Operations [Line Items]
Period after closing with which assets may be disposed to pay the amount as per agreement						18 months
Threshold period of receipt of consideration on disposal of assets based on which amount as per agreement shall be paid						10 years

Merger - Additional Information

Merger - Additional Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)
Merger [Line Items]
Selling, General and administrative expense	$ 9,900	$ 9,900
Business acquisition, Transaction costs	0	0
Other receivables	0	0
Payment of merger costs financing activities		1,200
Other Current Liabilities [Member]
Merger [Line Items]
Business combination transaction costs payable current	8,200	8,200
Accounts Payable and Accrued Liabilities [Member]
Merger [Line Items]
Business combination transaction costs payable current	$ 600	$ 600

Merger - Summary Of The Company

Merger - Summary Of The Company Obtain The Assets And Liabilities (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents	$ 85,230
Prepaid expenses and other current assets	319
Accounts payable	(1,988)
Accrued expenses and other current liabilities	(5,405)
Net assets acquired	$ 78,156

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Dec. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from simple agreement for future equity	$ 34,100
Common stock, shares, issued	2,634,246	14,734,323
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Fair value input amount transfer in between levels		$ 0	$ 0
Simple Agreements for Future Equity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock, shares, issued		2,752,216
Common stock, par or stated value per share		$ 12.4
Simple Agreements for Future Equity [Member] | AVROBIO [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common stock, shares, issued		1,470,839
Common stock, par or stated value per share		$ 12.4

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Assets	$ 100,442	$ 27,278
Liabilities:
Liabilities		30,515
SAFE Liabilities [Member]
Liabilities:
Liabilities		30,515
Money Market Funds [Member] | Cash Equivalents [Member]
Assets:
Assets	100,442	27,278
Fair Value, Inputs, Level 1 [Member]
Assets:
Assets	100,442	27,278
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member] | Cash Equivalents [Member]
Assets:
Assets	$ 100,442	27,278
Fair Value, Inputs, Level 3 [Member]
Liabilities:
Liabilities		30,515
Fair Value, Inputs, Level 3 [Member] | SAFE Liabilities [Member]
Liabilities:
Liabilities		$ 30,515

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Activity for the Safe Liabilities that were Measured at Fair Value (Detail) - SAFE Liabilities [Member] - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Opening Balance	$ 30,515	$ 0
Initial fair value recognition		31,515
Loss on issuance		255
Fair value adjustments	3,610	(1,255)
Ending Balance	0	$ 30,515
Conversion	$ (34,125)

Property, Equipment and Impro_3

Property, Equipment and Improvements, Net - Summary of Depreciation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation	$ 264	$ 246	$ 526	$ 476
General and administrative [Member]
Property, Plant and Equipment [Line Items]
Depreciation	5	4	9	8
Research and development [Member]
Property, Plant and Equipment [Line Items]
Depreciation	$ 259	$ 242	$ 517	$ 468

Property, Equipment and Impro_4

Property, Equipment and Improvements, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Property, Plant and Equipment [Abstract]
Depreciation	$ 264	$ 246	$ 526	$ 476

Property, Equipment and Impro_5

Property, Equipment and Improvements, Net - Summary of Property Equipment and Improvements Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	$ 5,021	$ 4,978
Less: accumulated depreciation	(2,382)	(1,856)
Property and equipment, net	2,639	3,122
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	4,554	4,510
Furniture and office equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	244	244
Computer equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	198	161
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment gross		38
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment gross	$ 25	$ 25

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Tectonic transaction costs	$ 8,215	$ 0
Accrued AVROBIO transaction costs	2,821	0
Employee compensation related costs	2,755	2,840
Accrued offering costs related to the Subscription Agreement	2,000	0
Accrued professional fees	1,607	1,798
Accrued contract research organization fees	985	2,298
Accrued contract development and manufacturing organization fees	649	660
Accrued office and laboratory costs	91	211
Other current liabilities	886	334
Total	$ 20,009	$ 8,141

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)

3 Months Ended

6 Months Ended

12 Months Ended

May 01, 2023

Jun. 30, 2024

Jun. 30, 2023

Jun. 30, 2024

Jun. 30, 2023

May 31, 2023

Dec. 31, 2022

Jul. 02, 2024

Dec. 31, 2023

Jul. 02, 2023

Jul. 02, 2022

Feb. 10, 2022

Nov. 29, 2021

Other Commitments [Line Items]

Accounts payable and accrued liabilities, current

$ 20,009,000

$ 20,009,000

$ 8,141,000

Indemnification Agreement [Member]

Other Commitments [Line Items]

Other commitment

0

0

$ 0

License Agreement [Member] | Harvard [Member]

Other Commitments [Line Items]

Non refundable license fee amount

$ 170,000

Due to related party

100,000

100,000

Cash paid to Harvard

$ 100,000

$ 100,000

$ 100,000

$ 200,000

License Agreement [Member] | Harvard [Member] | License [Member] | Maximum [Member]

Other Commitments [Line Items]

Percentage of non royalty income received

20%

20%

License Agreement [Member] | Harvard [Member] | License [Member] | Minimum [Member]

Other Commitments [Line Items]

Percentage of non royalty income received

10%

10%

License Agreement [Member] | Harvard [Member] | First Installment [Member]

Other Commitments [Line Items]

Payment of non refundable license fee amount

$ 56,666

License Agreement [Member] | Harvard [Member] | Second Installment [Member]

Other Commitments [Line Items]

Payment of non refundable license fee amount

$ 56,666

License Agreement [Member] | Harvard [Member] | Third Installment [Member]

Other Commitments [Line Items]

Payment of non refundable license fee amount

$ 56,668

License Agreement [Member] | Harvard [Member] | Common Stock [Member]

Other Commitments [Line Items]

Non refundable license fee shares

227,486

Non refundable license fee shares fair value

$ 400,000

License Agreement [Member] | Alloy Therapeutics, LLC [Member]

Other Commitments [Line Items]

Non refundable and non creditable annul fee

$ 100,000

Milestone payment

$ 4,800,000

Milestone fees

$ 0

100,000

$ 100,000

100,000

Discovery Agreement [Member] | Adimab, LLC [Member]

Other Commitments [Line Items]

Non refundable license fee shares fair value

$ 500,000

Payment of upfront technology access fee

$ 20,000

Percentage of actual full time employee performance

100%

Annual rate of performance obligation per full time employee

$ 400,000

Delivery fees

100,000

0

0

Target range of initial and completion fees payable

$ 400,000

Accounts payable and accrued liabilities, current

100,000

100,000

Payment towards quarterly funding

$ 200,000

$ 300,000

Discovery Agreement [Member] | Adimab, LLC [Member] | Maximum [Member]

Other Commitments [Line Items]

Payment towards quarterly funding

$ 100,000

$ 100,000

Leases - Additional Information

Leases - Additional Information (Detail) - ft²	1 Months Ended
	Nov. 30, 2020	Dec. 31, 2020
Operating Lease for Office and Laboratory Spaces [Member]
Lessee, Lease, Description [Line Items]
Area of real estate	18,768
Operating lease date of expiry	Jan. 31, 2026
Operating lease renewal term	5 years
Operating lease date of expiry revised	Apr. 21, 2022
Maximum [Member] | Operating Lease for Office and Laboratory Spaces [Member]
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term		3 years 6 months
Maximum [Member] | Finance Lease for Laboratory and Equipment [Member]
Lessee, Lease, Description [Line Items]
Finance lease remaining lease term		3 years 6 months
Minimum [Member] | Operating Lease for Office and Laboratory Spaces [Member]
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term		2 months
Minimum [Member] | Finance Lease for Laboratory and Equipment [Member]
Lessee, Lease, Description [Line Items]
Finance lease remaining lease term		2 months

Leases - Schedule of Effect of

Leases - Schedule of Effect of Lease Costs in the Company's Consolidated Statement of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Lease, Cost [Abstract]
Amortization of ROU assets	$ 115	$ 124	$ 230	$ 258
Interest on lease liabilities	28	39	59	81
Operating lease cost	351	351	702	702
Short-term lease cost	185	198	360	348
Variable lease cost	198	195	448	401
Total lease costs	$ 877	$ 907	$ 1,799	$ 1,790

Leases - Schedule of Informatio

Leases - Schedule of Information About the Company's Leases (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash Paid for Amounts included in the Measurement of Lease Liabilities [Abstract]
Finance leases - financing cash flows	$ 240	$ 270
Finance leases - operating cash flows	59	81
Operating leases - operating cash flows	$ 765	$ 489
Weighted-average remaining lease terms (in years)
Finance leases	2 years 9 months	3 years 8 months 23 days
Operating leases	1 year 7 months 2 days	2 years 7 months 2 days
Weighted-average discount rate
Finance leases	9.69%	9.58%
Operating leases	8.25%	8.25%

Leases - Schedule in Tabular Fo

Leases - Schedule in Tabular Form of Maturity of Operating and Finance Leases (Detail) $ in Thousands	Jun. 30, 2024 USD ($)
Leases [Abstract]
2024 (remaining)	$ 284
2024/2025	552
2025/2026	363
2026/2027	44
Total lease payments	1,243
Less: interest	(132)
Total lease liabilities	1,111
2024 (remaining)	769
2024/2025	1,580
2025/2026	132
Total lease payments	2,481
Less: interest	(148)
Total lease liabilities	$ 2,333

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Common stock, authorized	150,000,000	150,000,000
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, issued	14,734,323	2,634,246
Common stock, outstanding	14,734,323	2,634,246
Common stock, voting rights	Holders of voting common stock are entitled to one vote per share
Common stock, dividends, per share, declared	$ 0
Preferred Stock [Member]
Class of Stock [Line Items]
Common stock issuable upon conversion	3,647,675
Preferred stock, outstanding	0
Undesignated Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, outstanding	0
Preferred stock, issued	0
Unrestricted Common Stock [Member]
Class of Stock [Line Items]
Preferred stock, authorized	10,000,000
Common stock, outstanding	11,447

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation by share based award equity instruments other than options unvested and outstanding unrecognized compensation	$ 13,800		$ 13,800
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition			3 years 4 months 24 days
Proceeds from the exercise of stock options			$ 648	$ 1
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation by share based award equity instruments other than options non vested	11,447		11,447		18,968
2019 Equity Incentive Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Options Granted, Weighted-average grant-date fair value			$ 13.95	$ 2.51
Aggregate intrinsic value of options exercised	$ 3,700	$ 0	$ 3,700
Proceeds from the exercise of stock options	$ 600	$ 0	$ 600
2019 Equity Incentive Plan [Member] | Maximum [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Aggregate intrinsic value of options exercised				$ 100
Proceeds from the exercise of stock options				$ 100
2019 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation by share based award equity instruments other than options non vested	11,447		11,447
Share based compensation by share based award equity instruments other than options equity repurchase liability current	$ 100		$ 100
2024 Equity Incentive Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock, capital shares reserved for future issuance	1,938,799		1,938,799
Common stock capital shares reserved for future issuance term description			such aggregate number of shares of common stock will automatically increase on January 1st of each year for a period of ten years commencing on January 1, 2025 and ending on (and including) January 1, 2034, in an amount equal to 5% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase; provided
Common stock, other shares, outstanding	1,063,999		1,063,999
2024 Employee Stock Purchase Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock, capital shares reserved for future issuance	147,343		147,343
Common stock capital shares reserved for future issuance term description			the number of shares of common stock that are automatically added on January 1st of each year for a period of up to ten years commencing on January 1, 2025 and ending on (and including) January 1, 2034, in an amount equal to the lesser of (x) 1% of the total number of shares of common stock issued and outstanding determined as of the day prior to such increase and (y) a number of shares equal to three times the Initial ESPP Share Reserve.

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of the Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Issued and outstanding at June 30, 2024 | shares	1,002,485
Granted, Number of Shares | shares	874,800
Exercised, Number of Shares | shares	(266,705)
Forfeited and expired, Number of Shares | shares	(31,922)
Options assumed from AVROBIO upon Merger closing | shares	365,428
Closing Balance, Number of shares | shares	1,944,086	1,002,485
Options vested and exercisable, Number of Shares | shares	683,184
Options vested and expected to vest, Number of Shares | shares	1,944,086
Opening Balance, Weighted- Average Exercise Price | $ / shares	$ 3.11
Granted, Weighted- Average Exercise Price | $ / shares	16.8
Exercised, Weighted- Average Exercise Price | $ / shares	2.44
Forfeited and expired, Weighted- Average Exercise Price | $ / shares	2.71
Options assumed from AVROBIO upon Merger closing | $ / shares	89.92
Closing Balance, Weighted- Average Exercise Price | $ / shares	25.68	$ 3.11
Options vested and exercisable, Weighted- Average Exercise Price | $ / shares	49.36
Options vested and expected to vest, Weighted- Average Exercise Price | $ / shares	$ 25.68
Weighted-Average Remaining Contractual Term (Years)	7 years 6 months	8 years 2 months 12 days
Options vested and exercisable, Weighted-Average Remaining Contractual Term (Years)	3 years 9 months 18 days
Options vested and expected to vest, Weighted-Average Remaining Contractual Term (Years)	7 years 6 months
Opening Balance, Aggregate Intrinsic Value | $	$ 2,276
Exercised, Aggregate Intrinsic Value | $	3,743
Ending Balance, Aggregate Intrinsic Value | $	9,830	$ 2,276
Options vested and exercisable, Aggregate Intrinsic Value | $	4,987
Options vested and expected to vest, Aggregate Intrinsic Value | $	$ 9,830

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Fair Values of the Options Granted (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Fair value per share of underlying common stock	$ 16.8	$ 2.98
Expected term (in years)	6 years 3 months	5 years 11 months 4 days
Expected volatility ,Minimum		111.05%
Expected volatility ,Maximum	104%	111.21%
Risk-free interest rate	4.26%	3.65%
Expected dividend yield	0%	0%

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Restricted Stock Activity (Detail) - Restricted Common Stock [Member]	6 Months Ended
	Jun. 30, 2024 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested restricted common stock as of January 1, 2024	18,968
Early exercise of options	6,859
Vested	(14,380)
Unvested restricted common stock as of June 30, 2024	11,447

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock Based Compensation Expense Regarding its Employees and Nonemployees (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 403	$ 277	$ 724	$ 552
General and administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	228	175	421	349
Research and development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 175	$ 102	$ 303	$ 203

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes [Line Items]
Income tax expense benefit	$ 0	$ 0	$ 0	$ 0

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Net Income (Loss) Attributable to Parent [Abstract]
Net loss attributable to common stockholders, basic	$ (12,671)	$ (10,455)	$ (27,892)	$ (24,900)
Net loss attributable to common stockholders, diluted	$ (12,671)	$ (10,455)	$ (27,892)	$ (24,900)
Weighted-average common shares outstanding, basic	2,919,872	1,228,778	2,150,160	1,208,447
Weighted-average common shares outstanding, diluted	2,919,872	1,228,778	2,150,160	1,208,447
Net loss per share attributable to common stockholders, basic	$ (4.34)	$ (8.51)	$ (12.97)	$ (20.6)
Net loss per share attributable to common stockholders, diluted	$ (4.34)	$ (8.51)	$ (12.97)	$ (20.6)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	1,955,533	4,536,846	1,955,533	4,536,846
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	0	3,647,675	0	3,647,675
Stock 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	1,944,086	852,667	1,944,086	852,667
Unvested restricted common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	11,447	36,504	11,447	36,504

Related Party Transactions - A

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Related Party Transaction [Line Items]
Accounts payable current	$ 4,090	$ 409		$ 4,090
Member of the Scientific Advisory Board [Member] | Advisory Services Agreement [Member]
Related Party Transaction [Line Items]
Other payables current	100	0		100
Member of the Scientific Advisory Board [Member] | Advisory Services Agreement [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Professional fees	100		$ 100	100	$ 100
Harvard College [Member] | License Agreement [Member]
Related Party Transaction [Line Items]
License fees incurred				100	$ 200
Harvard College [Member] | License Agreement [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Accounts payable current	$ 100	100		$ 100
Related Party Investors [Member] | Simple Agreement For Future Equity [Member]
Related Party Transaction [Line Items]
Proceeds from financial instrument subject to mandatory redemption		$ 34,100

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 80	$ 52	$ 130	$ 128
Retirement Plan Name, Other [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan employee mathing contribution percentage			3%	3%
Defined contribution plan, cost	$ 100	$ 100	$ 100	$ 100

Employee Benefit Plan - Summary

Employee Benefit Plan - Summary of Defined Contribution Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Contribution Plan Disclosure [Line Items]
Total	$ 80	$ 52	$ 130	$ 128
Retirement Plan Name, Other [Member]
Defined Contribution Plan Disclosure [Line Items]
General and administrative	10	5	16	12
Research and development	70	47	114	116
Total	$ 100	$ 100	$ 100	$ 100