0000950170-24-122801 | 10-Q | XBRL Viewer

Accrued Expenses and Other Current Liabilities

9 Months Ended

Sep. 30, 2024

Accrued Expenses and Other Current Liabilities

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Research and development	$	1,236	$	2,645
Professional fees		312		459
Employee related		3,230		2,413
Accrued other		278		114
	$	5,056	$	5,631

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2024

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Summary of Fair Value Hierarchy of Assets and Liabilities Measured on Recurring Basis

The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value (in thousands):


	Fair Value Measurements at
	September 30, 2024
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	6,277	$	—	$	—	$	6,277
U.S. Treasury bills		—		—		—		—
Short-term investments:
U.S. Treasury bills, government securities, and government agency securities		—		281,347		—		281,347
	$	6,277	$	281,347	$	—	$	287,624


	Fair Value Measurements at
	December 31, 2023
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	23,441	$	—	$	—	$	23,441
U.S. Treasury bills		—		23,832		—		23,832
Short-term investments:
U.S. Treasury bills and government securities		—		77,309		—		77,309
	$	23,441	$	101,141	$	—	$	124,582
Liabilities
Series B preferred stock tranche right liability	$	—	$	—	$	4,200	$	4,200
	$	—	$	—	$	4,200	$	4,200

Schedule of Short-Term Investments

Short-term investments consisted of the following (in thousands):


	September 30, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Short-term investments:
U.S. Treasury bills, government securities, and government agency securities	$	280,946	$	401	$	—	$	281,347
	$	280,946	$	401	$	—	$	281,347


	December 31, 2023
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Short-term investments:
U.S. Treasury bills and government securities	$	77,305	$	4	$	—	$	77,309
	$	77,305	$	4	$	—	$	77,309

Summary of Contractual Maturities of Short-term Investments in Available-for-Sale Debt Securities

The contractual maturities of the Company’s short-term investments in available-for-sale debt securities held were as follows (in thousands):


	September 30,		December 31,
	2024		2023
Due within one year	$	216,496	$	77,309
Due between one and two years		64,851		—
	$	281,347	$	77,309

Series A Preferred Stock Tranche Right Liability

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Summary of Aggregate Fair Value Determined Using Level 3 Inputs

The following tables provide a roll-forward of the aggregate fair value of the Company’s Series A preferred stock tranche right liability during the nine months ended September 30, 2023, for which fair value is determined using Level 3 inputs (in thousands):


	Series A Preferred Stock Tranche Right Liability
Balance as of December 31, 2022	$	10,435
Change in fair value of Series A preferred stock tranche right liability		1,030
Settlement of Series A preferred stock tranche right liability upon waiver of milestone		(11,465	)
Balance as of September 30, 2023	$	—

Series B Preferred Stock Tranche Right Liability

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Summary of Aggregate Fair Value Determined Using Level 3 Inputs

The following tables provide a roll-forward of the aggregate fair value of the Company’s Series B preferred stock tranche right liability during the nine months ended September 30, 2024, for which fair value is determined using Level 3 inputs (in thousands):


	Series B Preferred Stock Tranche Right Liability
Balance as of December 31, 2023	$	4,200
Change in fair value of Series B preferred stock tranche right liability		7,390
Settlement of Series B preferred stock tranche right liability upon waiver of milestone		(11,590	)
Balance as of September 30, 2024	$	—

Summary of Fair Value Measurement Inputs Used in Valuation Model

The significant unobservable inputs used in the valuation model to measure the Series B preferred stock tranche right liability that is categorized within Level 3 of the fair value hierarchy as of December 31, 2023 are as follows:


	Second Tranche Milestone
Probability of meeting Series B milestone		80	%
Milestone achievement date	12/31/2024
Risk-free rate		4.79	%
Expected value of Series B if milestones are not met	$	0.84

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-3

+ Details

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Convertible Preferred Stock, beginning balance at Dec. 31, 2022		$ 29,567
Convertible Preferred Stock, beginning balance, shares at Dec. 31, 2022		40,182,354
Beginning balance at Dec. 31, 2022	$ (10,062)			$ 4	$ 586		$ (10,652)
Beginning balance, shares at Dec. 31, 2022				3,587,345
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs	11,465	$ 59,920			11,465
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs, shares		60,000,000
Issuance of restricted common stock	24				24
Issuance of restricted common stock, shares				273,166
Stock-based compensation expense	723				723
Net loss	(6,147)						(6,147)
Convertible Preferred Stock, ending balance at Mar. 31, 2023		$ 89,487
Convertible Preferred Stock, ending balance, shares at Mar. 31, 2023		100,182,354
Ending balance at Mar. 31, 2023	(3,997)			$ 4	12,798		(16,799)
Ending balance, shares at Mar. 31, 2023				3,860,511
Convertible Preferred Stock, beginning balance at Dec. 31, 2022		$ 29,567
Convertible Preferred Stock, beginning balance, shares at Dec. 31, 2022		40,182,354
Beginning balance at Dec. 31, 2022	(10,062)			$ 4	586		(10,652)
Beginning balance, shares at Dec. 31, 2022				3,587,345
Net loss	(21,267)
Convertible Preferred Stock, ending balance at Sep. 30, 2023		$ 89,487	$ 77,091
Convertible Preferred Stock, ending balance, shares at Sep. 30, 2023		100,182,354	51,273,790
Ending balance at Sep. 30, 2023	(13,117)			$ 4	18,798		(31,919)
Ending balance, shares at Sep. 30, 2023				4,170,817
Convertible Preferred Stock, beginning balance at Dec. 31, 2022		$ 29,567
Convertible Preferred Stock, beginning balance, shares at Dec. 31, 2022		40,182,354
Beginning balance at Dec. 31, 2022	(10,062)			$ 4	586		(10,652)
Beginning balance, shares at Dec. 31, 2022				3,587,345
Net loss	(34,800)
Convertible Preferred Stock, ending balance at Dec. 31, 2023	$ 166,578	$ 89,487	$ 77,091
Convertible Preferred Stock, ending balance, shares at Dec. 31, 2023	151,456,144	100,182,354	51,273,790
Ending balance at Dec. 31, 2023	$ (25,634)			$ 4	19,796	$ 4	(45,438)
Ending balance, shares at Dec. 31, 2023	4,170,817			4,170,817
Convertible Preferred Stock, beginning balance at Mar. 31, 2023		$ 89,487
Convertible Preferred Stock, beginning balance, shares at Mar. 31, 2023		100,182,354
Beginning balance at Mar. 31, 2023	$ (3,997)			$ 4	12,798		(16,799)
Beginning balance, shares at Mar. 31, 2023				3,860,511
Issuance of restricted common stock	30				30
Issuance of restricted common stock, shares				357,008
Stock-based compensation expense	945				945
Net loss	(6,411)						(6,411)
Convertible Preferred Stock, ending balance at Jun. 30, 2023		$ 89,487
Convertible Preferred Stock, ending balance, shares at Jun. 30, 2023		100,182,354
Ending balance at Jun. 30, 2023	(9,433)			$ 4	13,773		(23,210)
Ending balance, shares at Jun. 30, 2023				4,217,519
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs	2,887		$ 69,860		2,887
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs, shares			46,504,135
Issuance of convertible preferred stock for the settlement of the second tranche right liability, shares			4,769,655
Issuance of convertible preferred stock for the settlement of the second tranche right liability			$ 7,231
Issuance of convertible preferred stock for the settlement of the second tranche right liability	1,283				1,283
Issuance of restricted common stock	859
Stock-based compensation expense					859
Repurchase of unvested restricted common stock					(4)
Repurchase of unvested restricted common stock, shares				(46,702)
Net loss	(8,709)						(8,709)
Convertible Preferred Stock, ending balance at Sep. 30, 2023		$ 89,487	$ 77,091
Convertible Preferred Stock, ending balance, shares at Sep. 30, 2023		100,182,354	51,273,790
Ending balance at Sep. 30, 2023	(13,117)			$ 4	18,798		(31,919)
Ending balance, shares at Sep. 30, 2023				4,170,817
Convertible Preferred Stock, beginning balance at Dec. 31, 2023	$ 166,578	$ 89,487	$ 77,091
Convertible Preferred Stock, beginning balance, shares at Dec. 31, 2023	151,456,144	100,182,354	51,273,790
Beginning balance at Dec. 31, 2023	$ (25,634)			$ 4	19,796	4	(45,438)
Beginning balance, shares at Dec. 31, 2023	4,170,817			4,170,817
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs	$ 7,343		$ 68,161		7,343
Issuance of convertible preferred stock for the settlement of the tranche right liability, net of issuance costs, shares			38,157,240
Stock-based compensation expense	1,491				1,491
Net loss	(22,669)						(22,669)
Change in unrealized gain (loss) on investments, net of tax	(164)					(164)
Convertible Preferred Stock, ending balance at Mar. 31, 2024		$ 89,487	$ 145,252
Convertible Preferred Stock, ending balance, shares at Mar. 31, 2024		100,182,354	89,431,030
Ending balance at Mar. 31, 2024	(39,633)			$ 4	28,630	(160)	(68,107)
Ending balance, shares at Mar. 31, 2024				4,170,817
Convertible Preferred Stock, beginning balance at Dec. 31, 2023	$ 166,578	$ 89,487	$ 77,091
Convertible Preferred Stock, beginning balance, shares at Dec. 31, 2023	151,456,144	100,182,354	51,273,790
Beginning balance at Dec. 31, 2023	$ (25,634)			$ 4	19,796	4	(45,438)
Beginning balance, shares at Dec. 31, 2023	4,170,817			4,170,817
Net loss	$ (58,327)
Change in unrealized gain (loss) on investments, net of tax	396
Convertible Preferred Stock, ending balance, shares at Sep. 30, 2024		0	0
Ending balance at Sep. 30, 2024	$ 323,114			$ 36	426,443	400	(103,765)
Ending balance, shares at Sep. 30, 2024	36,576,457			36,576,457
Convertible Preferred Stock, beginning balance at Mar. 31, 2024		$ 89,487	$ 145,252
Convertible Preferred Stock, beginning balance, shares at Mar. 31, 2024		100,182,354	89,431,030
Beginning balance at Mar. 31, 2024	$ (39,633)			$ 4	28,630	(160)	(68,107)
Beginning balance, shares at Mar. 31, 2024				4,170,817
Conversion of Series A convertible preferred stock to common stock upon closing of the intial public offering	89,487	$ (89,487)		$ 12	89,475
Conversion of Series A convertible preferred stock to common stock upon closing of the intial public offering, shares		(100,182,354)		11,701,298
Conversion of Series B convertible preferred stock to common stock upon closing of the initial public offering	145,252		$ (145,252)	$ 10	145,242
Conversion of Series B Convertible Preferred Stock to Common Stock Upon Closing of the Initial Public Offering, Shares			(89,431,030)	10,445,518
Issuance of common stock from initial public offering, net of issuance costs	140,868			$ 9	140,859
Issuance of common stock from initial public offering, net of issuance costs, shares				9,200,000
Issuance of common stock from private placement, net of issuance cost	16,702			$ 1	16,701
Issuance of common stock from private placement, net of issuance cost, shares				1,058,824
Stock-based compensation expense	2,354				2,354
Net loss	(18,121)						(18,121)
Change in unrealized gain (loss) on investments, net of tax	(23)					(23)
Ending balance at Jun. 30, 2024	336,886			$ 36	423,261	(183)	(86,228)
Ending balance, shares at Jun. 30, 2024				36,576,457
Stock-based compensation expense	3,182				3,182
Net loss	(17,537)						(17,537)
Change in unrealized gain (loss) on investments, net of tax	583					583
Convertible Preferred Stock, ending balance, shares at Sep. 30, 2024		0	0
Ending balance at Sep. 30, 2024	$ 323,114			$ 36	$ 426,443	$ 400	$ (103,765)
Ending balance, shares at Sep. 30, 2024	36,576,457			36,576,457

Commitments and Contingencies

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnification of varying scopes and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with the board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any indemnification arrangements that could have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its condensed consolidated financial statements as of September 30, 2024 and December 31, 2023.

Legal Proceedings

From time to time, the Company may become involved in legal proceedings or other litigation relating to claims arising in the ordinary course of business. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and estimated exposure amount. Legal fees and other costs associated with such proceedings are expensed as incurred. As of September 30, 2024 and December 31, 2023, the Company was not a party to any material legal proceedings or claims.

NeuroPace Master Services Agreement and Statement of Work

In November 2023, the Company entered into a master services agreement (the “NeuroPace Agreement”) with NeuroPace Inc. (“NeuroPace”), the manufacturer and distributor of the RNS system. Pursuant to the NeuroPace Agreement and in accordance with statement of work agreements entered into from time to time, NeuroPace provides the Company with certain services with respect to data from the RNS systems used in our clinical trials. The NeuroPace Agreement also grants the Company a royalty-free, worldwide, exclusive, non-transferable license to all data collected by the RNS systems in its Phase 2a clinical trial and the outcomes of algorithms that are applied to such data, as well as the ability to publish the outcomes of algorithms, subject to certain conditions. The consideration the Company will pay to NeuroPace for such services is set out in each statement of work agreement.

The NeuroPace Agreement contains an exclusivity provision providing that, at any time while providing services under the NeuroPace Agreement and for a period after the final clinical study report, NeuroPace may not perform any services that are the same as the services covered by the NeuroPace Agreement to any business that directly competes with us, subject to the specific terms of the NeuroPace Agreement. The NeuroPace Agreement also contains standard representations and warranties, confidentiality and intellectual property protective provisions and indemnification terms.

The NeuroPace Agreement expires on the later of three years from the effective date or the completion of all services under all statement of work agreements entered into prior to the third anniversary of the effective date. Either party may terminate the NeuroPace Agreement or any statement of work agreement (i) without cause by giving written notice to the other party within a specified period of time, (ii) by giving written notice upon a curable material breach that is not remediated within a specified period of time, or (iii) immediately upon written notice in the event of a material breach that cannot be cured.

Concurrently with the execution of the NeuroPace Agreement, the parties also entered into an initial statement of work under the NeuroPace Agreement, as amended in March 2024 (the “NeuroPace SOW”), pursuant to which NeuroPace agreed to provide services related to the Company’s Phase 2a clinical trial of RAP-219, including, among other things, clinical trial readiness support, identification of potential patients satisfying the enrollment criteria and RNS system data reporting and data analysis. Pursuant to the payment schedule set out in the NeuroPace SOW, we will pay NeuroPace an aggregate of up to $3.7 million over a period of approximately two years in connection with NeuroPace’s provision of services and achievement of certain patient enrollment and deliverable milestones. During the three months ended September 30, 2024, the Company paid NeuroPace $0.1 million and

recognized $0.5 million in research and development expense for services performed. During the nine months ended September 30, 2024, the Company paid NeuroPace $0.5 million and recognized $1.1 million in research and development expense for services performed, resulting in a prepaid expense balance of $0.9 million as of September 30, 2024. As of December 31, 2023, $1.5 million was recorded as prepaid expenses and other current assets in the condensed consolidated balance sheet.

Fair Value Measurements - Schedule of Short-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, Amortized Cost	$ 280,946	$ 77,305
Short-term investments, Unrealized Gains		4
Short-term investments, Unrealized Losses	401
Short-term investments, Fair Value	281,347	77,309
U.S. Treasury Bills, Government Securities, and Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, Amortized Cost	280,946
Short-term investments, Unrealized Losses	401
Short-term investments, Fair Value	$ 281,347
U.S. Treasury Bills and Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments, Amortized Cost		77,305
Short-term investments, Unrealized Gains		4
Short-term investments, Fair Value		$ 77,309

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 103
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-103

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
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-Name Accounting Standards Codification
-Section 55
-Paragraph 100
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-100

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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-Section 50
-Paragraph 2
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details

Stock-Based Compensation

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

8. Stock-Based Compensation

2022 Plan

The 2022 Plan provides for the Company to grant incentive stock options (“ISO”) or non-qualified stock options, unrestricted stock awards, restricted stock awards and restricted stock units (collectively, the “Awards”) to the employees, directors, and consultants of the Company. The 2022 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board of directors. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or its committee if so delegated.

As of December 31, 2023, the total number of shares of common stock authorized and issuable under the 2022 Plan was 1,743,280. In March 2024, the Company’s board of directors increased the number of shares of common stock reserved for issuance under the plan from 1,743,280 to 2,948,559 shares. The remaining shares reserved for issuance under the 2022 Plan ceased to be available for issuance at the time that the 2024 Plan became effective. There will be no further awards granted under the 2022 Plan, but all outstanding awards under the 2022 Plan will continue to be governed by their existing terms.

Subsequent to the effectiveness of the 2024 Plan, the shares of common stock underlying any awards under the 2022 Plan that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of stock or otherwise terminated

(other than by exercise) and shares withheld upon exercise of an option or settlement of an award to cover the exercise price or tax withholding will be added to the shares of common stock available for issuance under the 2024 Plan.

2024 Plan

In May 2024, the Company’s board of directors adopted, and its stockholders approved, the 2024 Plan, which became effective in June 2024. The 2024 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors, and consultants. The 2024 plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares initially reserved for issuance under the 2024 Plan is 3,814,618 shares. In addition, the number of shares reserved and available for issuance under the 2024 Plan will automatically increase on January 1, 2025 and each January 1 thereafter, by five percent of the outstanding number of shares of common stock on the immediately preceding December 31 or such lesser number of shares as determined by the compensation committee. As of September 30, 2024, the Company had 2,586,014 shares remaining available for future grants.

The shares of common stock underlying any awards under the 2024 Plan and the 2022 Plan that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock, expire, or are otherwise terminated (other than by exercise) will be added back to the shares of common stock available for issuance under the 2024 Plan.

2024 ESPP

In May 2024, the Company’s board of directors adopted, and its stockholders approved, the 2024 ESPP, which became effective in June 2024. The 2024 ESPP initially reserved and authorized the issuance of up to a total of 324,243 shares of the Company’s common stock to participating employees. The 2024 ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1, 2025 and each January 1 thereafter through January 1, 2034, by the lesser of (i) 648,486 shares of common stock, (ii) one percent of the outstanding number of shares of common stock on the immediately preceding December 31, or (iii) such lesser number of shares of common stock as determined by the administrator of the 2024 ESPP. The number of shares reserved under the 2024 ESPP is subject to adjustment in the event of a stock split, stock dividend or other change in our capitalization.

No shares were issued during the three and nine months ended September 30, 2024 relating to the 2024 ESPP.

Stock Options

The Company has granted stock options with service-based vesting conditions. Stock options generally vest over four years and have a maximum term of ten years. The Company typically grants stock options to employees and non-employees at exercise prices deemed by the Board to be equal to the fair value of the common stock at the time of grant. The following table summarizes the Company’s stock option activity for the nine months ended September 30, 2024:


	Number of Shares			Weighted- Average Exercise Price per share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2023		1,376,596		$	1.80		9.83	$	6,249
Granted		2,645,079			13.05
Exercised		—			—
Forfeited		(23,350	)		4.24
Expired		—			—
Options outstanding at September 30, 2024		3,998,325		$	9.23		9.35	$	44,985
Options vested and exercisable at September 30, 2024		281,573			2.15		8.61		5,110
Options vested and expected to vest at September 30, 2024		3,998,325		$	9.23		9.35	$	44,985

The weighted-average grant-date fair value of stock options granted during the nine months ended September 30, 2024 was $10.78 per share, and there were no options granted during the nine months ended September 30, 2023. As of September 30, 2024,

there was $31.3 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a remaining weighted average period of 3.48 years.

Restricted Stock Awards (“RSA”)

The Company awards restricted stock both under the 2022 Plan as well as outside of the 2022 Plan.

Service-Based RSAs

The majority of the RSAs have service-based vesting conditions and vest over a period from immediately to four years. Compensation expense is recognized on a straight-line basis over the requisite service period.

The following table summarizes the Company’s service-based RSA grant activity for the nine months ended September 30, 2024:


	RSAs			Weighted- Average Grant Date Fair Value
Unvested shares at December 31, 2023		1,585,998		$	3.64
Granted		—			—
Vested		(470,944	)		3.56
Forfeited		—			—
Unvested shares at September 30, 2024		1,115,054		$	3.68

The aggregate fair value of service-based RSAs that vested during the nine months ended September 30, 2024 and 2023, was $0.5 million and $7.1 million, respectively. As of September 30, 2024, there was $3.9 million of total unrecognized compensation cost related to unvested service-based RSAs, which is expected to be recognized over a remaining weighted average period of 2.25 years.

Performance-Based RSAs

The Company has also granted performance-based RSAs to certain employees and directors with a vesting commencement date contingent upon the subsequent closing of the Company’s Series A convertible preferred stock financing. The Company has determined that it has met all the conditions to establish the grant date for these performance-based RSAs at the original issuance date. Therefore, these awards are deemed to contain an implied performance condition. The vesting of the performance-based RSAs is also subject to grantees’ continued service until the 4th anniversary date of the closing of a subsequent financing.

Share-based compensation expense associated with the performance-based RSAs is recognized if the performance condition is considered probable of achievement. In February 2023, the existing Series A convertible preferred stock investors waived the second and third tranche milestones and the Company closed on the sale of its second and third tranches of Series A convertible preferred stock. As a result, the performance condition was deemed to be met.

The following table summarizes the Company’s performance-based RSA grant activity for the nine months ended September 30, 2024:


	RSAs			Weighted- Average Grant Date Fair Value
Unvested shares at December 31, 2023		649,264		$	3.63
Granted		—			—
Vested		(153,773	)		3.63
Forfeited		—			—
Unvested shares at September 30, 2024		495,491		$	3.63

The aggregate fair value of performance-based RSAs that vested during the nine months ended September 30, 2024 and 2023 was $2.3 million and $0.6 million, respectively. As of September 30, 2024, there was $0.5 million of total unrecognized compensation cost related to unvested performance-based restricted common stock, which is expected to be recognized over a remaining weighted average period of 2.10 years.

Stock-Based Compensation

The Company recorded stock-based compensation expense for stock options of $2.5 million and zero in the three months ended September 30, 2024 and 2023, respectively, and $5.0 million and zero in the nine months ended September 30, 2024 and 2023, respectively. The Company recorded stock-based compensation expense for RSAs of $0.7 million and $0.9 million in the three months ended September 30, 2024 and 2023, respectively, and $2.1 million and $2.5 million in the nine months ended September 30, 2024 and 2023, respectively. The following table below summarizes the classification of the Company’s stock-based compensation expense related to stock options and restricted common stock awards in the consolidated statements of operations and comprehensive loss (in thousands):


	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2024		2023		2024		2023
General and Administrative	$	1,990	$	428	$	4,110	$	1,125
Research and Development		1,192		431		2,917		1,402
	$	3,182	$	859	$	7,027	$	2,527

Preferred Stock - Additional Information (Details)			1 Months Ended				3 Months Ended			9 Months Ended		12 Months Ended
Preferred Stock - Additional Information (Details)	Sep. 01, 2023 USD ($) Stockholders shares	Aug. 31, 2023 USD ($) Stockholders $ / shares shares	Mar. 31, 2024 USD ($) $ / shares shares	Feb. 29, 2024 USD ($)	Feb. 28, 2023 USD ($) $ / shares shares	Dec. 31, 2022 $ / shares shares	Mar. 31, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Mar. 31, 2023 USD ($) shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) $ / shares shares	Jun. 07, 2024 shares	May 30, 2024 $ / shares shares	Jan. 31, 2024 USD ($)	Jan. 01, 2023 shares
Temporary Equity [Line Items]
Preferred stock, shares authorized \| shares														10,000,000
Preferred stock, par value \| $ / shares														$ 0.001
Converted aggregate common shares \| shares													22,146,816
Number of shares issued \| shares												151,456,144
Series B preferred stock tranche right liability												$ 4,200,000
Non-cumulative dividends rate on original issue price										8.00%
Dividends										$ 0		$ 0
Percentage of voting stock on closing of transfer, minimum										50.00%
Minimum
Temporary Equity [Line Items]
Common stock, underwritten public offering, price per share \| $ / shares										$ 14.70302
Gross Proceeds, Net of Underwriting Discount and Commissions										$ 50,000,000
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Number of shares issued \| shares					50,000,000	32,000,000				0		100,182,354				40,182,354
Additional number of shares issued \| shares									60,000,000
Shares issued, price per share \| $ / shares					$ 1	$ 1
Debt conversion, shares issued \| shares						8,182,354
Proceeds from issuance of convertible preferred stock					$ 50,000,000						$ 59,920,000
Issuance costs									$ 87,000
Settlement of preferred stock tranche right liability					11,500,000
Preferred stock, convertible, conversion price \| $ / shares												$ 8.5648
Series A Convertible Preferred Stock \| Maximum
Temporary Equity [Line Items]
Issuance costs					$ 61,000
Series A Convertible Preferred Stock \| Series A Milestone Tranches
Temporary Equity [Line Items]
Number of shares issued \| shares					50,000,000
Additional number of shares issued \| shares						60,000,000
Shares issued, price per share \| $ / shares					$ 1	$ 1
Stock issued during period, shares \| shares					10,000,000
Proceeds from issuance of convertible preferred stock					$ 10,000,000
Issuance costs					$ 19,000
Series B Convertible Preferred Stock
Temporary Equity [Line Items]
Number of shares issued \| shares		46,504,135								0		51,273,790
Additional number of shares issued \| shares							38,157,240	46,504,135
Shares issued, price per share \| $ / shares		$ 1.67727
Stock issued during period, shares \| shares								4,769,655
Proceeds from issuance of convertible preferred stock										$ 63,913,000	$ 85,306,000
Issuance costs							$ 87,000	$ 632,000
Series B preferred stock tranche right liability												$ 4,200,000			$ 11,600,000
Series B preferred stock tranche right liability recognized in other expense															$ 7,400,000
Preferred stock, convertible, conversion price \| $ / shares												$ 14.3655
Series B Convertible Preferred Stock \| Series B Milestone Tranches
Temporary Equity [Line Items]
Number of shares issued \| shares		42,926,895
Shares issued, price per share \| $ / shares		$ 1.67727
Series B preferred stock tranche right liability		$ 4,600,000
Series B Convertible Preferred Stock \| Series B Second Tranche Milestone
Temporary Equity [Line Items]
Number of shares issued \| shares			38,157,240				38,157,240
Shares issued, price per share \| $ / shares			$ 1.67727				$ 1.67727
Proceeds from issuance of convertible preferred stock			$ 64,000,000
Settlement of preferred stock tranche right liability			4,200,000
Series B preferred stock tranche right liability				$ 4,200,000
Additional paid-in capital, as capital contribution, fair value				$ 7,400,000
Series B Convertible Preferred Stock \| Series B Second Tranche Milestone \| Maximum
Temporary Equity [Line Items]
Issuance costs			$ 87,000
Series B Convertible Preferred Stock Early Exercised
Temporary Equity [Line Items]
Stock issued during period, shares \| shares		10,731,725
Series B Convertible Preferred Stock Early Exercised \| Series B Milestone Tranches
Temporary Equity [Line Items]
Number of shares issued \| shares	4,769,655	10,731,725
Proceeds from issuance of convertible preferred stock	$ 8,000,000
Number of stockholders exercised, right to early exercise \| Stockholders	1	6
Additional paid in capital, preferred stock	$ 500,000	$ 1,200,000
Premium paid as a capital contribution	$ 800,000	$ 1,700,000

Property and Equipment, Net

9 Months Ended

Sep. 30, 2024

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

4. Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	September 30, 2024			December 31, 2023
Lab equipment	$	3,691		$	1,719
Computer equipment		68			43
Leasehold improvements		281			255
Construction in process		74			26
Total property and equipment		4,114			2,043
Less: Accumulated depreciation		(705	)		(127	)
	$	3,409		$	1,916

Depreciation expense of property and equipment for the three months ended September 30, 2024 and 2023 was $0.2 million and $23 thousand, respectively. Depreciation expense of property and equipment for the nine months ended September 30, 2024 and 2023 was $0.6 million and $59 thousand, respectively.

Net Loss per Share - Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss Per Share Available to Common Shareholders (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	3,998,325
Series A \| Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		100,182,354
Series B \| Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		51,273,790
Service Based \| Unvested Restricted Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,115,054	1,943,797
Performance Based \| Unvested Restricted Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	495,491	700,526

Nature of the Business and Basis of Presentation - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended						9 Months Ended		12 Months Ended
	May 31, 2024	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Nature of the Business and Basis of Presentation [Line Items]
Common stock reserved for future issuance									one-for-8.5648
Reverse stock split conversion ratio	0.11675
Net loss			$ (17,537)	$ (18,121)	$ (22,669)	$ (8,709)	$ (6,411)	$ (6,147)	$ (58,327)	$ (21,267)	$ (34,800)
Accumulated deficit			(103,765)						(103,765)		$ (45,438)
Net proceeds from public offering		$ 157,600
Cash and cash equivalents and short-term investments excluding restricted cash			$ 320,700						$ 320,700

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483499/205-20-50-7

Reference 34: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 35: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1A

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-1B

Reference 37: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

+ Details

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

Preferred Stock (Tables)

9 Months Ended

Sep. 30, 2024

Temporary Equity Disclosure [Abstract]

Schedule of Conversions of Preferred Stock

Convertible preferred stock consisted of the following (in thousands, except share amounts):


	December 31, 2023
	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Conversion Price per share		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		100,182,354		100,182,354	$	89,487	$	100,182	$	8.5648		11,701,298
Series B convertible preferred stock		89,431,030		51,273,790		77,091		86,000	$	14.3655		5,988,764
		189,613,384		151,456,144	$	166,578	$	186,182				17,690,062

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (17,537)	$ (18,121)	$ (22,669)	$ (8,709)	$ (6,411)	$ (6,147)	$ (58,327)	$ (21,267)	$ (34,800)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Stock-Based Compensation - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 07, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Mar. 31, 2024	Feb. 29, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares granted				2,645,079
Stock-based compensation expense		$ 3,182,000	$ 859,000	$ 7,027,000	$ 2,527,000
Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period				4 years
Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period				10 years
Service-Based RSAs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period				4 years
Total unrecognized compensation cost related to unvested stock options		3,900,000		$ 3,900,000
Stock-based compensation expense, expected weighted average period for recognition				2 years 3 months
Aggregate fair value of service-based and performance-based RSAs, vested				$ 500,000	7,100,000
Performance-Based RSAs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unrecognized compensation cost related to unvested stock options		500,000		$ 500,000
Stock-based compensation expense, expected weighted average period for recognition				2 years 1 month 6 days
Aggregate fair value of service-based and performance-based RSAs, vested				$ 2,300,000	600,000
Stock Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense		2,500,000	0	$ 5,000,000	$ 0
Weighted-average grant-date fair value of stock options granted				$ 10.78	$ 0
Total unrecognized compensation cost related to unvested stock options		31,300,000		$ 31,300,000
Stock-based compensation expense, expected weighted average period for recognition				3 years 5 months 23 days
Restricted Stock Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense		$ 700,000	$ 900,000	$ 2,100,000	$ 2,500,000
2022 Stock Option and Grant Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock reserved		2,746,371		2,746,371		1,743,280
2022 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock reserved and authorized for issuance						1,743,280
Number of common stock reserved							2,948,559	1,743,280
Number of shares granted						0
2024 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock reserved		3,814,618		3,814,618
Number of shares granted				2,586,014
Annual automatic increases in the number of shares		5.00%		5.00%
2024 ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock reserved and authorized for issuance	324,243
Number of common stock reserved		324,243		324,243
Number of shares granted		0		0
Number of additional shares allowable under the plan	648,486
Percentage of outstanding shares	1.00%
2024 Stock Option and Grant Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock reserved		3,814,618		3,814,618

Fair Value Measurements - Summary of Contractual Maturities of Short-term Investments in Available-for-Sale Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract]
Short-term investments, Due within one year	$ 216,496	$ 77,309
Short-term investments, Due between one and two years	64,851	0
Short-term investments	$ 281,347	$ 77,309

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

+ Details

Preferred Stock - Schedule of Conversions of Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Aug. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Feb. 28, 2023	Jan. 01, 2023	Dec. 31, 2022
Temporary Equity [Line Items]
Preferred stock authorized			189,613,384
Preferred stock issued			151,456,144
Preferred stock outstanding			151,456,144
Carrying value			$ 166,578
Liquidation preference			$ 186,182
Common stock issuable upon conversion			17,690,062
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred stock authorized	0		100,182,354
Preferred stock issued	0		100,182,354					50,000,000	40,182,354	32,000,000
Preferred stock outstanding	0	100,182,354	100,182,354	100,182,354		100,182,354	100,182,354			40,182,354
Carrying value		$ 89,487	$ 89,487	$ 89,487		$ 89,487	$ 89,487			$ 29,567
Liquidation preference	$ 0		$ 100,182
Conversion price per share			$ 8.5648
Common stock issuable upon conversion			11,701,298
Series B Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred stock authorized	0		89,431,030
Preferred stock issued	0		51,273,790		46,504,135
Preferred stock outstanding	0	89,431,030	51,273,790	51,273,790
Carrying value		$ 145,252	$ 77,091	$ 77,091
Liquidation preference	$ 0		$ 86,000
Conversion price per share			$ 14.3655
Common stock issuable upon conversion			5,988,764

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity for the nine months ended September 30, 2024:


	Number of Shares			Weighted- Average Exercise Price per share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2023		1,376,596		$	1.80		9.83	$	6,249
Granted		2,645,079			13.05
Exercised		—			—
Forfeited		(23,350	)		4.24
Expired		—			—
Options outstanding at September 30, 2024		3,998,325		$	9.23		9.35	$	44,985
Options vested and exercisable at September 30, 2024		281,573			2.15		8.61		5,110
Options vested and expected to vest at September 30, 2024		3,998,325		$	9.23		9.35	$	44,985

Summary of Restricted Stock Awards Grant Activity

The following table summarizes the Company’s service-based RSA grant activity for the nine months ended September 30, 2024:


	RSAs			Weighted- Average Grant Date Fair Value
Unvested shares at December 31, 2023		1,585,998		$	3.64
Granted		—			—
Vested		(470,944	)		3.56
Forfeited		—			—
Unvested shares at September 30, 2024		1,115,054		$	3.68

Summary of Performance-based RSA Grant Activity

The following table summarizes the Company’s performance-based RSA grant activity for the nine months ended September 30, 2024:


	RSAs			Weighted- Average Grant Date Fair Value
Unvested shares at December 31, 2023		649,264		$	3.63
Granted		—			—
Vested		(153,773	)		3.63
Forfeited		—			—
Unvested shares at September 30, 2024		495,491		$	3.63

Summary of Share-based Compensation Expense

The following table below summarizes the classification of the Company’s stock-based compensation expense related to stock options and restricted common stock awards in the consolidated statements of operations and comprehensive loss (in thousands):


	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2024		2023		2024		2023
General and Administrative	$	1,990	$	428	$	4,110	$	1,125
Research and Development		1,192		431		2,917		1,402
	$	3,182	$	859	$	7,027	$	2,527

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

There have been no significant changes from the significant accounting policies and estimates disclosed in Note 2 of the “Notes to Consolidated Financial Statements” in the audited consolidated financial statements for the year ended December 31, 2023 and notes thereto, included in the Company’s IPO final prospectus filed pursuant to Rule 424(b) (4) under the Securities Act with the SEC on June 7, 2024.

Use of Estimates

The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected within these condensed consolidated financial statements include, but are not limited to, research and development expenses and accruals, the valuation of the Company’s common stock and stock-based awards and the valuation of preferred stock tranche right liability. The Company bases its estimates on known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ materially from those estimates or assumptions.

Concentrations of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains its cash and cash equivalents at high-quality and accredited financial institutions in amounts that could exceed federally insured limits. Cash equivalents are invested in money market funds and U.S. Treasury bills. However, the Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s short-term investments consist of U.S. Treasury bills, government securities, and government agency securities and as a result, the Company believes represent minimal credit risk.

Restricted cash

Restricted cash as of December 31, 2023 consisted of a letter of credit totaling $85 thousand that was established in connection with an anticipated lease arrangement, which was cancelled prior to commencement due to failure of the landlord to complete its obligations. Consequently, the letter of credit and related cash restriction were released in March 2024. Restricted cash at September 30, 2024 was $0.1 million, which was restricted as cash collateral for the Company’s business credit card program.

Short-term investments

The Company’s short-term investments consist of investments in debt securities, including U.S. Treasury bills, government securities, and U.S. agency securities with remaining maturities beyond three months at the date of purchase that are available to be converted into cash to fund its current operations. As of September 30, 2024 and December 31, 2023, all of the Company’s debt

securities were classified as available-for-sale and were carried at fair market value (see Note 3). The unrealized gains and losses on the Company’s available-for-sale debt securities are recorded in other comprehensive income (loss) in the condensed consolidated statements of operations and comprehensive loss.

Debt securities in an unrealized loss position are evaluated for impairment at least quarterly. For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether or not it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the investment security’s amortized cost basis is written down to fair value through net loss.

For available-for-sale debt securities that do not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In conducting this assessment for debt securities in an unrealized loss position, management evaluates the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors.

If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the investment security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any unrealized loss that has not been recorded through an allowance for credit loss is recognized in other comprehensive income (loss). As of September 30, 2024 and December 31, 2023, there was no allowance for credit losses recorded on the Company’s condensed consolidated balance sheet.

The Company’s interest income consists of interest earned from cash, cash equivalents, and short-term investments.

Deferred Offering Costs

The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded as a reduction of the proceeds from the offering, either as a reduction of the carrying value of the convertible preferred stock or in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should the in-process equity financing be abandoned, the deferred offering costs would be expensed immediately as a charge to operating expenses in the condensed consolidated statements of operations and comprehensive loss. Upon closing of the Company’s IPO in June 2024, these deferred offering costs were included in the $16.8 million issuance costs classified to stockholders equity (deficit) and recorded against the proceeds from the offering. As of December 31, 2023, the Company recorded deferred offering costs of $0.3 million in other assets on its condensed balance sheet.

Net Loss Per Share

The Company calculated basic and diluted net loss per share attributable to common stockholders using the two-class method required for companies with participating securities. The Company considers Series A convertible preferred stock and Series B convertible preferred stock to be participating securities as the holders are entitled to receive cumulative dividends as well as residuals in liquidation.

Under the two-class method, basic net loss per share available to common stockholders was calculated by dividing the net loss available to common stockholder by the weighted-average number of shares of common stock outstanding during the period, which excludes unvested restricted stock. The net loss available to common stockholders was not allocated to the Series A convertible preferred stock or Series B convertible preferred stock as the holders of convertible preferred stock did not have a contractual obligation to share in losses. Diluted net loss per share available to common stockholders was computed by giving effect to all potentially dilutive common stock equivalents outstanding for the period. For purposes of this calculation, preferred stock, unvested restricted stock and stock options were considered common stock equivalents but had been excluded from the calculation of diluted net loss per share available to common stockholders as their effect was anti-dilutive. In periods in which the Company reports a net loss available to common stockholders, diluted net loss per share available to common stockholders is the same as basic net loss per share available to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Following the closing of its IPO, the Company only has one class of shares outstanding, and basic net loss per common share is computed by dividing the net loss by the weighted average number of shares of common stock outstanding for the period. Diluted net

loss per common share is computed by dividing net loss by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock awards. For periods in which the Company reports a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Comprehensive Loss

Comprehensive loss includes net loss as well as other changes in stockholders’ deficit that result from transactions and economic events other than those with stockholders. For both the three and nine months ended September 30, 2024, comprehensive loss is partially offset by unrealized gains on short-term investments. For both the three and nine months ended September 30, 2023, there was no difference between net loss and comprehensive loss.

Recently Issued Accounting Pronouncements Not Yet Adopted

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which requires all public entities, including public entities with a single reportable segment, to provide in interim and annual periods one or more measures of segment profit or loss used by the chief operating decision maker to allocate resources and assess performance. Additionally, the standard requires disclosures of significant segment expenses and other segment items as well as incremental qualitative disclosures. The guidance in this update is effective for fiscal years beginning after December 15, 2023, and interim periods after December 15, 2024. The Company is currently in the process of evaluating the effects of this pronouncement on its related disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”), which requires enhanced income tax disclosures, including specific categories and disaggregation of information in the effective tax rate reconciliation, disaggregated information related to income taxes paid, income or loss from continuing operations before income tax expense or benefit, and income tax expense or benefit from continuing operations. The requirements of the ASU are effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently in the process of evaluating the impact of this pronouncement on its related disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires disclosures about specific types of expenses included in the expense captions presented on the face of the income statement as well as disclosures about selling expenses. The requirements of the ASU are effective for annual periods beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The requirements will be applied prospectively with the option for retrospective application. The Company is currently in the process of evaluating the effects of this pronouncement on its related disclosures.

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Summary of Significant Accounting Policies [Line Items]
Restricted cash	$ 105,000	$ 85,000
Allowance for credit losses	0	0
Deferred offering costs		300,000	$ 6,000
Issuance costs	$ 16,800,000
Letter of Credit
Summary of Significant Accounting Policies [Line Items]
Restricted cash		$ 85,000

Stock-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,182	$ 859	$ 7,027	$ 2,527
General and Administrative
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,990	428	4,110	1,125
Research and Development
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 1,192	$ 431	$ 2,917	$ 1,402

Net Loss per Share

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Net Loss per Share

12. Net Loss per Share

Basic and diluted net loss per common share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Numerator:
Net loss attributable to common stockholders	$	(17,537	)	$	(8,709	)	$	(58,327	)	$	(21,267	)
Denominator:
Weighted average common shares outstanding, basic and diluted		34,855,907			1,529,216			15,925,777			1,444,666
Net loss per share attributable to common stockholders, basic and diluted	$	(0.50	)	$	(5.70	)	$	(3.66	)	$	(14.72	)

For purposes of this calculation, the Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share available to common shareholders for the periods indicated because including them would have had an anti-dilutive effect:


	As of September 30,
	2024		2023
Series A convertible preferred stock		—		100,182,354
Series B convertible preferred stock		—		51,273,790
Options to purchase common stock		3,998,325		—
Unvested restricted common stock—service based		1,115,054		1,943,797
Unvested restricted common stock—performance based		495,491		700,526

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)

Sep. 30, 2024

Dec. 31, 2023

Convertible preferred stock, shares authorized

189,613,384

Convertible preferred stock, shares issued

151,456,144

Convertible preferred stock, shares outstanding

151,456,144

Convertible preferred stock, liquidation preference

$ 186,182,000

Common stock, par value

$ 0.001

Common stock, shares authorized

500,000,000

250,000,000

Common stock, shares issued

36,576,457

4,170,817

Common stock, shares outstanding

36,576,457

4,170,817

Accounts payable

^[1]

$ 1,323,000

$ 2,502,000

Accrued expenses

^[1]

5,056,000

5,631,000

Third Rock Ventures LLC

Accounts payable

200,000

Third Rock Ventures LLC | Maximum

Accrued expenses

$ 100,000

$ 0

Series A Convertible Preferred Stock

Convertible preferred stock, par value

$ 0.001

Convertible preferred stock, shares authorized

100,182,354

Convertible preferred stock, shares issued

100,182,354

Convertible preferred stock, shares outstanding

100,182,354

Convertible preferred stock, liquidation preference

$ 0

$ 100,182,000

Series B Convertible Preferred Stock

Convertible preferred stock, par value

$ 0.001

Convertible preferred stock, shares authorized

89,431,030

Convertible preferred stock, shares issued

51,273,790

Convertible preferred stock, shares outstanding

51,273,790

Convertible preferred stock, liquidation preference

$ 0

$ 86,000,000

[1]	Includes related party amounts of zero and $0.2 million (accounts payable) and less than $0.1 million and zero (accrued expenses) as of September 30, 2024 and December 31, 2023, respectively (see Notes 5 and 10).

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

1 Months Ended

3 Months Ended

9 Months Ended

Mar. 31, 2024

Nov. 30, 2023

Sep. 30, 2024

Sep. 30, 2023

Sep. 30, 2024

Sep. 30, 2023

Dec. 31, 2023

Loss Contingencies [Line Items]

Prepaid expenses and other current assets

$ 5,173,000

$ 3,309,000

Research and development expense

^[1]

15,543,000

$ 7,580,000

43,736,000

$ 16,200,000

NeuroPace Agreement

Loss Contingencies [Line Items]

Master services agreement, expiration period

3 years

Amount paid

100,000

500,000

Research and development expense

500,000

1,100,000

Balance of prepaid expense

$ 900,000

NeuroPace SOW

Loss Contingencies [Line Items]

Period cost covered

2 years

Prepaid expenses and other current assets

$ 1,500,000

NeuroPace SOW | Maximum

Loss Contingencies [Line Items]

Payment for service provided

$ 3,700,000

[1]	Includes related party amounts of zero for each of the three months ended September 30, 2024 and 2023, and less than $0.1 million and $0.5 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2024

Sep. 30, 2023

Sep. 30, 2024

Sep. 30, 2023

Operating expenses

Research and development

^[1]

$ 15,543

$ 7,580

$ 43,736

$ 16,200

General and administrative

^[2]

6,097

1,984

15,798

5,185

Total operating expenses

21,640

9,564

59,534

21,385

Loss from operations

(21,640)

(9,564)

(59,534)

(21,385)

Other income (expense):

Interest income

4,103

856

8,597

1,152

Change in fair value of preferred stock tranche right liability

(7,390)

(1,030)

Total other income, net

4,103

856

1,207

122

Net loss before income taxes

(17,537)

(8,708)

(58,327)

(21,263)

Provision for income taxes

Net loss

$ (17,537)

$ (8,709)

$ (58,327)

$ (21,267)

Net loss per share attributable to common stockholders, basic

$ (0.5)

$ (5.7)

$ (3.66)

$ (14.72)

Net loss per share attributable to common stockholders, diluted

$ (0.5)

$ (5.7)

$ (3.66)

$ (14.72)

Weighted-average common shares outstanding, basic

34,855,907

1,529,216

15,925,777

1,444,666

Weighted-average common shares outstanding, diluted

34,855,907

1,529,216

15,925,777

1,444,666

Comprehensive loss:

Net loss

$ (17,537)

$ (8,709)

$ (58,327)

$ (21,267)

Change in unrealized gains (losses) on investments, net of tax

583

396

Total other comprehensive income (loss)

583

396

Comprehensive loss

$ (16,954)

$ (8,709)

$ (57,931)

$ (21,267)

[1]	Includes related party amounts of zero for each of the three months ended September 30, 2024 and 2023, and less than $0.1 million and $0.5 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).
[2]	Includes related party amounts of zero and $0.2 million for the three months ended September 30, 2024 and 2023, respectively and $0.1 million and $0.7 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).

Stock-Based Compensation - Summary of Performance-based RSA Grant Activity (Details) - Performance-Based RSAs	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested RSAs, Beginning balance \| shares	649,264
Vested, RSAs \| shares	(153,773)
Unvested RSAs, Ending balance \| shares	495,491
Unvested, Weighted Average Grant Date Fair Value, Beginning balance \| $ / shares	$ 3.63
Vested, Weighted Average Grant Date Fair Value \| $ / shares	3.63
Unvested, Weighted Average Grant Date Fair Value, Ending balance \| $ / shares	$ 3.63

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Paragraph 3
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-URI https://asc.fasb.org/1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2003/role/disclosureRef
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Fair Value Measurements - Summary of Fair Value Hierarchy of Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets:
Assets, fair value	$ 287,624	$ 124,582
Liabilities
Liabilities, fair value		4,200
Money Market Funds
Assets:
Cash equivalents	6,277	23,441
U.S. Treasury Bills
Assets:
Cash equivalents		23,832
U.S. Treasury Bills, Government Securities, and Government Agency Securities
Assets:
Short-term investments	281,347
U.S. Treasury Bills and Government Securities
Assets:
Short-term investments		77,309
Series B Preferred Stock Tranche Right Liability
Liabilities
Liabilities, fair value		4,200
Level 1
Assets:
Assets, fair value	6,277	23,441
Level 1 \| Money Market Funds
Assets:
Cash equivalents	6,277	23,441
Level 2
Assets:
Assets, fair value	281,347	101,141
Level 2 \| U.S. Treasury Bills
Assets:
Cash equivalents		23,832
Level 2 \| U.S. Treasury Bills, Government Securities, and Government Agency Securities
Assets:
Short-term investments	$ 281,347
Level 2 \| U.S. Treasury Bills and Government Securities
Assets:
Short-term investments		77,309
Level 3
Liabilities
Liabilities, fair value		4,200
Level 3 \| Series B Preferred Stock Tranche Right Liability
Liabilities
Liabilities, fair value		$ 4,200

Fair Value Measurements - Summary of Fair Value Measurement Inputs Used in Valuation Model (Details) - Level 3 - Series B Preferred Stock Tranche Right Liability	Sep. 30, 2024
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Milestone achievement date	Dec. 31, 2024
Probability of Meeting Series B Milestone
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	80
Risk-Free Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	4.79
Expected Value of Series B if Milestones are Not Met
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.84

Related Party Transactions - Additional Information (Details) - USD ($)

1 Months Ended

3 Months Ended

9 Months Ended

Jun. 30, 2024

Sep. 30, 2024

Jun. 30, 2024

Sep. 30, 2023

Sep. 30, 2024

Sep. 30, 2023

Dec. 31, 2023

Research and development expense

^[1]

$ 15,543,000

$ 7,580,000

$ 43,736,000

$ 16,200,000

General and administrative expense

^[2]

6,097,000

$ 1,984,000

15,798,000

5,185,000

Accounts payable

^[3]

1,323,000

$ 2,502,000

Accrued expenses

^[3]

5,056,000

5,631,000

Common Stock

Additional share purchased

9,200,000

IPO | Common Stock

Additional share purchased

9,200,000

Janssen

Costs incurred

69,000

200,000

100,000

1,000,000

Research and development expense

300,000

General and administrative expense

100,000

$ 700,000

Accounts payable

200,000

Accrued expenses

$ 0

[1]	Includes related party amounts of zero for each of the three months ended September 30, 2024 and 2023, and less than $0.1 million and $0.5 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).
[2]	Includes related party amounts of zero and $0.2 million for the three months ended September 30, 2024 and 2023, respectively and $0.1 million and $0.7 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).
[3]	Includes related party amounts of zero and $0.2 million (accounts payable) and less than $0.1 million and zero (accrued expenses) as of September 30, 2024 and December 31, 2023, respectively (see Notes 5 and 10).

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2024	Nov. 06, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Trading Symbol	RAPP
Entity Registrant Name	Rapport Therapeutics, Inc.
Entity Central Index Key	0002012593
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Entity File Number	001-42121
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	88-0724208
Entity Address, Address Line One	1325 Boylston Street
Entity Address, Address Line Two	Suite 401
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02215
City Area Code	857
Local Phone Number	321-8020
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		36,576,457

Related Party Transactions

9 Months Ended

Sep. 30, 2024

Related Party Transactions

10. Related Party Transactions

Janssen

Janssen Pharmaceutical NV (“Janssen”) is a related party to a founding investor in the Company, Johnson & Johnson Innovation—JJDC, Inc., as both entities are direct subsidiaries of Johnson & Johnson, Inc. For the nine months ended September 30, 2024 and 2023, the Company incurred costs of $69 thousand and $0.2 million, respectively, which was recognized as research and development expense in the condensed consolidated statement of operations and comprehensive loss, to Janssen for the use of lab space in California. As of September 30, 2024 and December 31, 2023, there were no related party transactions in accounts payable or accrued expenses.

Third Rock Ventures

Third Rock Ventures LLC (“Third Rock”) is a founding investor in the Company. For the nine months ended September 30, 2024 and 2023, the Company incurred costs of $0.1 million and $1.0 million, respectively, of which zero and $0.3 million, respectively, was recognized as research and development expense, and $0.1 million and $0.7 million, respectively, was recognized as

general and administrative expense in the condensed consolidated statement of operations and comprehensive loss to Third Rock primarily for management consulting and other various start-up support activities. As of September 30, 2024 and December 31, 2023, zero and $0.2 million, respectively, was included in accounts payable. As of both September 30, 2024 and December 31, 2023, there were no accrued expenses related to Third Rock.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147477968/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

+ Details

Preferred Stock

9 Months Ended

Sep. 30, 2024

Temporary Equity Disclosure [Abstract]

Preferred Stock

6. Preferred Stock

Prior to the closing of the Company's IPO in June 2024, the Company had issued Series A convertible preferred stock and Series B convertible preferred stock.

On May 30, 2024, the Company’s stockholders approved the third amended and restated certificate of incorporation, which was filed upon the closing of the IPO on June 10, 2024, and which, among other things, created 10,000,000 undesignated shares of authorized preferred stock, $0.001 par value per share.

Immediately prior to the closing of the Company’s IPO on June 6, 2024, pursuant to the reverse stock split and a proportional adjustment to the existing conversion ratios of each series of the Company’s preferred stock as discussed further below, all of the Company’s outstanding shares of convertible preferred stock were converted into an aggregate of 22,146,816 shares of common stock.

Series A Convertible Preferred Stock and Series A Preferred Stock Tranche Right Liability

In December 2022, the Company completed its first closing of Series A convertible preferred stock and issued and sold 32,000,000 shares of Series A convertible preferred stock, at a price of $1.00 per share. Contemporaneously, investors converted their Convertible Promissory Notes for 8,182,354 shares of Series A convertible preferred stock, bringing the total number of shares of Series A convertible preferred stock issued to 40,182,354.

The purchase agreement for the Series A convertible preferred stock provided investors the obligation to purchase an additional 60,000,000 shares of Series A convertible preferred stock (the “Series A Milestone Tranches”) at a price of $1.00 per share in the subsequent second and third tranche closings upon the achievement of specified second and third tranche milestones by the Company or the right to purchase additional shares upon waiving of such milestone achievement by a majority vote of Series A convertible preferred stockholders. Within 30 days prior to a Deemed Liquidation Event (see definition below), investors could also choose to early exercise their tranche right by providing the Company a written notice.

In February 2023, the Company amended the Series A convertible preferred stock purchase agreement to add an additional investor, who purchased 10,000,000 shares, at the price of $1.00 per share, resulting in cash proceeds of $10.0 million, less $19 thousand of issuance costs and to amend the total number of shares subject to the Series A Milestone Tranches from 60,000,000 to 50,000,000.

In conjunction with the amendment to the Series A convertible preferred stock purchase agreement, the Company’s existing Series A convertible preferred stockholders agreed to waive the second and third tranche milestones and exercised the tranche right in February 2023. As a result, an aggregate of 50,000,000 shares of Series A convertible preferred stock were issued and sold at a price of $1.00 per share, resulting in total cash proceeds of $50 million, less $61 thousand of issuance costs. As a result of this issuance, the Series A preferred stock tranche right liability with a then fair value of $11.5 million immediately prior to the amendment and waiver, was settled in full and recognized in additional paid-in capital as a capital contribution.

Series B Convertible Preferred Stock and Series B Preferred Stock Tranche Right Liability

In August 2023, the Company issued and sold 46,504,135 shares of Series B convertible preferred stock, at a price of $1.67727 per share. The 46,504,135 shares include the 10,731,725 shares that were early exercised on the original issuance date (discussed below).

The purchase agreement for the Series B convertible preferred stock provided investors the obligation to purchase an additional 42,926,895 shares of Series B convertible preferred stock (the “Series B Milestone Tranche”) at a price of $1.67727 per share in the subsequent closing upon the achievement of a specified milestone by the Company or the right to purchase additional shares upon waiving of such milestone achievement by a majority vote of Series B convertible preferred stockholders. Additionally, each stockholder of Series B convertible preferred stock had the right to early exercise the tranche right by providing three days advance written notice. Upon the closing of the Series B convertible preferred stock, the Company recorded a preferred stock tranche right liability of $4.6 million and a corresponding reduction to the carrying value of the Series B convertible preferred stock.

Concurrent with the original issuance of the Series B convertible preferred stock, six stockholders exercised their right to early exercise the Series B preferred stock tranche right and purchased 10,731,725 shares. Consequently, the Company recognized $1.2 million in additional paid-in capital associated with the simultaneous original issuance and early exercise. Additionally, the investors paid a premium of $1.7 million for these shares over their fair value which was also recorded in additional paid-in capital as a capital contribution.

Subsequent to the original issuance in August 2023, one stockholder exercised its right to early exercise the Series B preferred stock tranche right and purchased 4,769,655 shares of Series B convertible preferred stock for cash proceeds of $8.0 million. The fair

value of the associated tranche right liability that was settled at the time of the sale of $0.5 million was recognized in additional paid-in capital. Additionally, the investor paid a premium of $0.8 million for these shares over their fair value which was also recorded in additional paid-in capital as a capital contribution.

As of December 31, 2023, the Company remeasured the Series B tranche right liability to be $4.2 million.

In February 2024, the Company’s Series B convertible preferred stockholders voted to waive the second tranche milestones and purchase the remaining Series B Milestone Tranche shares. Immediately prior to the waiver, the Company remeasured the Series B tranche right liability to be $11.6 million and recognized $7.4 million in other expense for the change in the fair value of the Series B tranche right liability during the period. As a result of the waiver, the Company remeasured the Series B tranche right liability to be $4.2 million and recognized the change in fair value of $7.4 million in additional paid-in capital, as a capital contribution. In conjunction with the closing that occurred in March 2024, an aggregate of 38,157,240 shares of Series B convertible preferred stock were issued at a price of $1.67727 per share, resulting in total cash proceeds of $64.0 million, less $87 thousand of issuance costs. As a result of this issuance, the Series B preferred stock tranche right liability with a then fair value of $4.2 million was settled in full and recognized as part of the carrying value of the Series B convertible preferred stock.

Upon issuance of each series of Preferred Stock, the Company assessed the embedded conversion and liquidation features of the securities and determined that such features did not require the Company to separately account for these features.

Convertible preferred stock consisted of the following (in thousands, except share amounts):


	December 31, 2023
	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Conversion Price per share		Common Stock Issuable Upon Conversion
Series A convertible preferred stock		100,182,354		100,182,354	$	89,487	$	100,182	$	8.5648		11,701,298
Series B convertible preferred stock		89,431,030		51,273,790		77,091		86,000	$	14.3655		5,988,764
		189,613,384		151,456,144	$	166,578	$	186,182				17,690,062

In June 2024, all of the Company’s outstanding shares of convertible preferred stock were converted into shares of common stock.

The holders of the convertible preferred stock had the following rights and preferences:

Voting

The holders of the convertible preferred stock were entitled to vote, together with the holders of common stock, as a single class, on all matters submitted to the shareholders for a vote and were entitled to the number of votes equal to the number of shares of common stock into which the convertible preferred stock could convert on the record date for determination of shareholders entitled to vote. A majority vote of the holders of convertible preferred stock along with a majority vote of the Series B convertible preferred stock (the “Required Vote”) was required to, among others, liquidate or dissolve the Company, amend the certificate of incorporation or bylaws, reclassify common stock or establish another class of capital stock, create shares that would rank senior to or authorize additional shares of convertible preferred stock, declare a dividend or make a distribution, or change the authorized number of directors constituting the board of directors.

In addition, the holders of shares of Series A convertible preferred stock, voting exclusively and as a separate class, were entitled to elect up to three directors of the Company. The holders of shares of Series B convertible preferred stock, voting exclusively and as a separate class, were entitled to elect up to two directors of the Company.

Conversion

Each share of Series A convertible preferred stock was convertible into common stock, at any time, at the option of the holder, and without the payment of additional consideration, at the applicable conversion ratio then in effect, provided that such holder may waive such option to convert upon written notice to the Company. Holders of Series B convertible preferred stock were not entitled to

elect to convert shares of Series B convertible preferred stock into shares of Common Stock at any time during the period commencing on the date of the first issuance of the Series B convertible preferred stock and ending immediately following the earliest to occur of (i) the Series B Milestone Tranche closing, (ii) the achievement of the second tranche milestone, (iii) the date such holder’s obligation to purchase its Second Tranche Shares is fulfilled, (iv) the termination of such holder’s obligations to complete the Series B Milestone Tranche closing and (v) such date as agreed to by the Company and the holders of a majority of the then outstanding shares of Series B convertible preferred stock, voting as a separate, exclusive class. In addition, each share of convertible preferred stock would be automatically converted into shares of common stock at the then-effective applicable conversion ratio upon either (i) the closing of a firm-commitment underwritten public offering of its common stock at a price per share of at least $14.70302 resulting in at least $50.0 million of gross proceeds, net of underwriting discount and commissions, to the Company, or (ii) the date specified by vote or written consent of the holders of the Required Vote, voting as a single class.

The conversion ratio of each class of convertible preferred stock was determined by dividing the Applicable Original Issue Price of each class of convertible preferred stock by the Conversion Price of each class. As of December 31, 2023, the Conversion Price was $8.5648 per share for Series A convertible preferred stock and $14.3655 per share for Series B convertible preferred stock, each subject to appropriate adjustment in the event of any share dividend, share split, combination or other similar recapitalization with respect to the convertible preferred stock. All outstanding convertible preferred stock was converted into common stock immediately prior to the closing of the Company’s IPO.

There shall be no adjustment in the conversion price of the convertible preferred stock as the result of the issuance or deemed issuance of additional shares of the Company’s common stock if the Company receives written notice from the holders of the Required Vote of the then outstanding shares of convertible preferred stock agreeing that no such adjustment shall be made as the result of the issuance or deemed issuance of additional shares of the Company’s common stock.

In the event that any holder of convertible preferred stock who was required to participate in a subsequent closing pursuant to the purchase agreement did not purchase the aggregate number of subsequent closing shares, then each share of convertible preferred stock held by such holder shall automatically be converted into shares of common stock at a ratio of one share of common stock for every ten shares of convertible preferred stock held immediately prior to the consummation of such subsequent closing.

Dividends

The holders of the convertible preferred stock were entitled to receive, only when, as and if declared by the Board of Directors, non-cumulative dividends at the rate of 8% of the Applicable Original Issue Price of the convertible preferred stock (the “Preferred Dividend”).

The Company shall not declare, pay or set aside any dividends on common shares of the Company unless the holders of convertible preferred stock then outstanding first received, or simultaneously received, the Preferred Dividend on each outstanding convertible preferred stock and a dividend on each outstanding convertible preferred stock in an amount at least equal to the product of (1) the dividend payable on each share of such class or series determined, as if all shares of such class or series had been converted into common stock and (2) the number of shares of common stock issuable upon conversion of a share of such series of convertible preferred stock, in each case calculated on the record date for determination of the holders entitled to receive such dividend. As of both September 30, 2024 and December 31, 2023, no cash dividends have been declared or paid.

Liquidation

In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company, or upon the occurrence of a Deemed Liquidation Event (as defined below), the holders of shares of convertible preferred stock then outstanding were entitled, on a pari passu basis among the series of convertible preferred stock, to be paid out of the assets or funds of the Company available for distribution to stockholders before any payment was made to the holders of common stock. The holders of convertible preferred stock were entitled to an amount per share equal to the greater of (i) the Applicable Original Issue Price, plus any dividends declared but unpaid thereon, or (ii) the amount that would have been payable had all shares of each series of convertible preferred stock been converted into common stock immediately prior to such liquidation, dissolution, winding up or Deemed Liquidation Event (as defined below). After the payment in full of the convertible preferred stock preference amount, the remaining assets of the Company available for distribution to stockholders shall be distributed among the holders of common stock on a pro rata basis.

Unless at least the holders of the Required Vote, elect otherwise, a Deemed Liquidation Event shall include a merger, consolidation, or share exchange (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 a sale, lease, transfer, exclusive license or other disposition of all or substantially all of the assets of the Company, or the closing of the transfer of 50% or more of the Company’s outstanding voting stock, or any merger or consolidation in connection with a SPAC transaction or reverse merger transaction.

Redemption

The convertible preferred stock did not have redemption rights, except for the contingent redemption upon the occurrence of a Deemed Liquidation Event.

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected within these condensed consolidated financial statements include, but are not limited to, research and development expenses and accruals, the valuation of the Company’s common stock and stock-based awards and the valuation of preferred stock tranche right liability. The Company bases its estimates on known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ materially from those estimates or assumptions.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains its cash and cash equivalents at high-quality and accredited financial institutions in amounts that could exceed federally insured limits. Cash equivalents are invested in money market funds and U.S. Treasury bills. However, the Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company’s short-term investments consist of U.S. Treasury bills, government securities, and government agency securities and as a result, the Company believes represent minimal credit risk.
Restricted cash	Restricted cash Restricted cash as of December 31, 2023 consisted of a letter of credit totaling $85 thousand that was established in connection with an anticipated lease arrangement, which was cancelled prior to commencement due to failure of the landlord to complete its obligations. Consequently, the letter of credit and related cash restriction were released in March 2024. Restricted cash at September 30, 2024 was $0.1 million, which was restricted as cash collateral for the Company’s business credit card program.
Short-term investments	Short-term investments The Company’s short-term investments consist of investments in debt securities, including U.S. Treasury bills, government securities, and U.S. agency securities with remaining maturities beyond three months at the date of purchase that are available to be converted into cash to fund its current operations. As of September 30, 2024 and December 31, 2023, all of the Company’s debt securities were classified as available-for-sale and were carried at fair market value (see Note 3). The unrealized gains and losses on the Company’s available-for-sale debt securities are recorded in other comprehensive income (loss) in the condensed consolidated statements of operations and comprehensive loss. Debt securities in an unrealized loss position are evaluated for impairment at least quarterly. For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether or not it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the investment security’s amortized cost basis is written down to fair value through net loss. For available-for-sale debt securities that do not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In conducting this assessment for debt securities in an unrealized loss position, management evaluates the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the investment security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any unrealized loss that has not been recorded through an allowance for credit loss is recognized in other comprehensive income (loss). As of September 30, 2024 and December 31, 2023, there was no allowance for credit losses recorded on the Company’s condensed consolidated balance sheet. The Company’s interest income consists of interest earned from cash, cash equivalents, and short-term investments.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded as a reduction of the proceeds from the offering, either as a reduction of the carrying value of the convertible preferred stock or in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should the in-process equity financing be abandoned, the deferred offering costs would be expensed immediately as a charge to operating expenses in the condensed consolidated statements of operations and comprehensive loss. Upon closing of the Company’s IPO in June 2024, these deferred offering costs were included in the $16.8 million issuance costs classified to stockholders equity (deficit) and recorded against the proceeds from the offering. As of December 31, 2023, the Company recorded deferred offering costs of $0.3 million in other assets on its condensed balance sheet.
Net Loss Per Share	Net Loss Per Share The Company calculated basic and diluted net loss per share attributable to common stockholders using the two-class method required for companies with participating securities. The Company considers Series A convertible preferred stock and Series B convertible preferred stock to be participating securities as the holders are entitled to receive cumulative dividends as well as residuals in liquidation. Under the two-class method, basic net loss per share available to common stockholders was calculated by dividing the net loss available to common stockholder by the weighted-average number of shares of common stock outstanding during the period, which excludes unvested restricted stock. The net loss available to common stockholders was not allocated to the Series A convertible preferred stock or Series B convertible preferred stock as the holders of convertible preferred stock did not have a contractual obligation to share in losses. Diluted net loss per share available to common stockholders was computed by giving effect to all potentially dilutive common stock equivalents outstanding for the period. For purposes of this calculation, preferred stock, unvested restricted stock and stock options were considered common stock equivalents but had been excluded from the calculation of diluted net loss per share available to common stockholders as their effect was anti-dilutive. In periods in which the Company reports a net loss available to common stockholders, diluted net loss per share available to common stockholders is the same as basic net loss per share available to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Following the closing of its IPO, the Company only has one class of shares outstanding, and basic net loss per common share is computed by dividing the net loss by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per common share is computed by dividing net loss by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock awards. For periods in which the Company reports a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ deficit that result from transactions and economic events other than those with stockholders. For both the three and nine months ended September 30, 2024, comprehensive loss is partially offset by unrealized gains on short-term investments. For both the three and nine months ended September 30, 2023, there was no difference between net loss and comprehensive loss.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which requires all public entities, including public entities with a single reportable segment, to provide in interim and annual periods one or more measures of segment profit or loss used by the chief operating decision maker to allocate resources and assess performance. Additionally, the standard requires disclosures of significant segment expenses and other segment items as well as incremental qualitative disclosures. The guidance in this update is effective for fiscal years beginning after December 15, 2023, and interim periods after December 15, 2024. The Company is currently in the process of evaluating the effects of this pronouncement on its related disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”), which requires enhanced income tax disclosures, including specific categories and disaggregation of information in the effective tax rate reconciliation, disaggregated information related to income taxes paid, income or loss from continuing operations before income tax expense or benefit, and income tax expense or benefit from continuing operations. The requirements of the ASU are effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently in the process of evaluating the impact of this pronouncement on its related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires disclosures about specific types of expenses included in the expense captions presented on the face of the income statement as well as disclosures about selling expenses. The requirements of the ASU are effective for annual periods beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The requirements will be applied prospectively with the option for retrospective application. The Company is currently in the process of evaluating the effects of this pronouncement on its related disclosures.

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Sep. 30, 2023 USD ($)
Series B Convertible Preferred Stock
Issuance costs	$ 632
Tranch right liability issued	$ 4,619

Leases - Additional Information (Details) - USD ($)	1 Months Ended
Leases - Additional Information (Details) - USD ($)	Jun. 30, 2023	Sep. 30, 2024	Feb. 29, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating lease right of use asset, net		$ 1,607,000		$ 2,084,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Operating lease right of use asset, net
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Operating Lease, Liability, Current
Corporate Headquarters Boston, Massachusetts
Lessee, Lease, Description [Line Items]
Operating lease term of contract	40 months
Operating lease, payments first 12 months	$ 66,000
Operating lease, percentage of escalation	2.00%
Operating lease, security deposit		$ 100,000
Laboratory and Office Space San Diego, California
Lessee, Lease, Description [Line Items]
Operating lease term of contract			5 years
Operating Lease, Payments	$ 9,600,000
Operating lease right of use asset, net		0
Operating lease, liability		$ 0

Stock-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Shares, Options outstanding beginning balance \| shares	1,376,596
Number of Shares, Granted \| shares	2,645,079
Number of Shares, Forfeited \| shares	(23,350)
Number of Shares, Options outstanding ending balance \| shares	3,998,325	1,376,596
Number of Shares, Options vested and exercisable \| shares	281,573
Number of Shares, Options vested and expected to vest \| shares	3,998,325
Weighted- Average Exercise Price per share, options outstanding beginning balance \| $ / shares	$ 1.8
Weighted- Average Exercise Price per share, granted \| $ / shares	13.05
Weighted- Average Exercise Price per share, forfeited \| $ / shares	4.24
Weighted- Average Exercise Price per share, options outstanding ending balance \| $ / shares	9.23	$ 1.8
Weighted- Average Exercise Price per share, Options vested and exercisable \| $ / shares	2.15
Weighted- Average Exercise Price per share, Options vested and expected to vest \| $ / shares	$ 9.23
Weighted- Average Remaining Contractual Term, Options outstanding	9 years 4 months 6 days	9 years 9 months 29 days
Weighted- Average Remaining Contractual Term, Options vested and exercisable	8 years 7 months 9 days
Weighted- Average Remaining Contractual Term, Options vested and expected to vest	9 years 4 months 6 days
Aggregate Intrinsic Value, Options outstanding \| $	$ 44,985	$ 6,249
Aggregate Intrinsic Value, Options vested and exercisable \| $	5,110
Aggregate Intrinsic Value, Options vested and expected to vest \| $	$ 44,985

Fair Value Measurements - Summary of Aggregate Fair Value Determined Using Level 3 Inputs (Details) - Level 3 - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Series A Preferred Stock Tranche Right Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Beginning Balance		$ 10,435
Change in fair value of preferred stock tranche right liability		1,030
Settlement of preferred stock tranche right liability upon waiver of milestone		(11,465)
Fair Value, Ending Balance		$ 0
Series B Preferred Stock Tranche Right Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Beginning Balance	$ 4,200
Change in fair value of preferred stock tranche right liability	7,390
Settlement of preferred stock tranche right liability upon waiver of milestone	(11,590)
Fair Value, Ending Balance	$ 0

Fair Value Measurements - Additional Information (Details)	Sep. 30, 2024 $ / shares
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net asset value	$ 1

- Definition

Net asset value per share or per unit of investments in certain entities that calculate net asset value per share. Includes, but is not limited to, by unit, membership interest, or other ownership interest. Investment includes, but is not limited to, investment in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Excludes fair value disclosure.

+ References + Details

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)
$ in Thousands

Sep. 30, 2024

Dec. 31, 2023

Current assets

Cash and cash equivalents

$ 39,314

$ 70,169

Short-term investments

281,347

77,309

Restricted cash

105

Prepaid expenses and other current assets

5,173

3,309

Total current assets

325,939

150,872

Property and equipment, net

3,409

1,916

Operating lease right of use asset, net

1,607

2,084

Other assets

189

551

Total assets

331,144

155,423

Current liabilities

Accounts payable

^[1]

1,323

2,502

Accrued expenses and other current liabilities

^[1]

5,056

5,631

Operating lease liability

720

670

Total current liabilities

7,099

8,803

Series B preferred stock tranche right liability

4,200

Operating lease liability, net of current portion

931

1,476

Total liabilities

8,030

14,479

Commitments and Contingencies

Convertible preferred stock

166,578

Stockholders' equity (deficit)

Common stock, $0.001 par value; 500,000,000 shares and 250,000,000 shares authorized at September, 30, 2024 and December 31, 2023, respectively; 36,576,457 shares and 4,170,817 shares issued and outstanding as of September, 30, 2024 and December 31, 2023, respectively

Additional paid-in capital

426,443

19,796

Accumulated other comprehensive income

400

Accumulated deficit

(103,765)

(45,438)

Total stockholders' equity (deficit)

323,114

(25,634)

Total liabilities, convertible preferred stock, and stockholders' equity

$ 331,144

155,423

Series A Convertible Preferred Stock

Current liabilities

Convertible preferred stock

89,487

Series B Convertible Preferred Stock

Current liabilities

Series B preferred stock tranche right liability

4,200

Convertible preferred stock

$ 77,091

[1]	Includes related party amounts of zero and $0.2 million (accounts payable) and less than $0.1 million and zero (accrued expenses) as of September 30, 2024 and December 31, 2023, respectively (see Notes 5 and 10).

Common Stock - Additional Information (Details)		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
Common Stock - Additional Information (Details)	May 31, 2024	Jun. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) shares	Dec. 31, 2023 USD ($) shares	May 30, 2024 shares	May 29, 2024 shares
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized				500,000,000	250,000,000
Reverse stock split conversion ratio	0.11675
Common stock reserved for future issuance				one-for-8.5648
Net proceeds from public offering \| $		$ 157,600,000
2022 Stock Option and Grant Plan
Subsidiary, Sale of Stock [Line Items]
Number of common stock reserved				2,746,371	1,743,280
2024 Stock Option and Grant Plan
Subsidiary, Sale of Stock [Line Items]
Number of common stock reserved				3,814,618
2024 ESPP
Subsidiary, Sale of Stock [Line Items]
Number of common stock reserved				324,243
Series A Convertible Preferred Stock and Series B Convertible Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Number of common stock reserved					22,146,816
IPO
Subsidiary, Sale of Stock [Line Items]
Underwriting discounts and commissions and offering costs \| $			$ 15,519,000
Private Placement
Subsidiary, Sale of Stock [Line Items]
Underwriting discounts and commissions and offering costs \| $			$ 1,297,000
Common Stock
Subsidiary, Sale of Stock [Line Items]
Voting right, description				Each share of common stock entitles the holder to one vote
Dividends \| $				$ 0	$ 0
Common stock, shares authorized						500,000,000	250,000,000
Issuance of common stock from IPO			9,200,000
Issuance of common stock from private placement			1,058,824
Number of common stock reserved				6,885,232	23,890,096
Common Stock \| IPO
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock from IPO		9,200,000
Net proceeds from public offering \| $		$ 140,900,000
Shares issued, price per share \| $ / shares		$ 17	$ 17
Underwriting discounts and commissions and offering costs \| $		$ 15,500,000
Common Stock \| Private Placement
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock from private placement		1,058,824
Net proceeds from private placement \| $		$ 16,700,000
Shares issued, price per share \| $ / shares		$ 17	$ 17
Underwriting discounts and commissions and offering costs \| $		$ 1,300,000

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 4,114	$ 2,043
Less: Accumulated depreciation	(705)	(127)
Property and equipment, net	3,409	1,916
Lab Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	3,691	1,719
Computer Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	68	43
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	281	255
Construction In Process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 74	$ 26

Stock-Based Compensation - Summary of Restricted Stock Awards Grant Activity (Details) - Service-Based RSAs	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested RSAs, Beginning balance \| shares	1,585,998
Vested, RSAs \| shares	(470,944)
Unvested RSAs, Ending balance \| shares	1,115,054
Weighted-Average Grant-Date Fair Value
Unvested, Weighted Average Grant Date Fair Value, Beginning balance \| $ / shares	$ 3.64
Vested, Weighted Average Grant Date Fair Value \| $ / shares	3.56
Unvested, Weighted Average Grant Date Fair Value, Ending balance \| $ / shares	$ 3.68

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Fair Value Measurements

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements


	Fair Value Measurements at
	September 30, 2024
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	6,277	$	—	$	—	$	6,277
U.S. Treasury bills		—		—		—		—
Short-term investments:
U.S. Treasury bills, government securities, and government agency securities		—		281,347		—		281,347
	$	6,277	$	281,347	$	—	$	287,624


	Fair Value Measurements at
	December 31, 2023
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	23,441	$	—	$	—	$	23,441
U.S. Treasury bills		—		23,832		—		23,832
Short-term investments:
U.S. Treasury bills and government securities		—		77,309		—		77,309
	$	23,441	$	101,141	$	—	$	124,582
Liabilities
Series B preferred stock tranche right liability	$	—	$	—	$	4,200	$	4,200
	$	—	$	—	$	4,200	$	4,200

Money market funds are highly liquid and actively traded marketable securities that generally transact at a stable $1.00 net asset value representing its estimated fair value. During the year ended December 31, 2023 and the three and nine months ended September 30, 2024, there were no transfers between Level 1, Level 2 and Level 3.

The Company classifies its U.S. Treasury securities as short-term because they are available to be converted into cash to fund current operations. The fair value of the Company’s U.S. Treasury bills, government securities, and government agency securities are classified as Level 2 because they are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency and U.S. Treasury securities.

The underlying securities held in the money market funds held by the Company are all government backed securities.

Short-term investments consisted of the following (in thousands):


	September 30, 2024
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Short-term investments:
U.S. Treasury bills, government securities, and government agency securities	$	280,946	$	401	$	—	$	281,347
	$	280,946	$	401	$	—	$	281,347


	December 31, 2023
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
Short-term investments:
U.S. Treasury bills and government securities	$	77,305	$	4	$	—	$	77,309
	$	77,305	$	4	$	—	$	77,309

The contractual maturities of the Company’s short-term investments in available-for-sale debt securities held were as follows (in thousands):


	September 30,		December 31,
	2024		2023
Due within one year	$	216,496	$	77,309
Due between one and two years		64,851		—
	$	281,347	$	77,309

As of September 30, 2024, all investments in an unrealized loss position were in this position for less than 12 months. The Company evaluated its securities for potential other-than-temporary impairment and considered the decline in market value to be primarily attributable to current economic and market conditions. Additionally, the Company does not intend to sell the securities in an unrealized loss position and does not expect it will be required to sell the securities before recovery of the unamortized cost basis. Given the Company’s intent and ability to hold such securities until recovery, and the lack of a significant change in credit risk for these investments, the Company does not consider these investments to be impaired as of September 30, 2024. The Company did not recognize any credit losses during both the three and nine months ended September 30, 2024.

Valuation of Preferred Stock Tranche Right Liability

The Series A and Series B preferred stock tranche right liabilities in the tables above and below are composed of the fair value of obligations to issue Series A convertible preferred stock and Series B convertible preferred stock, respectively (see Note 6), either upon achievement of certain specified milestones, upon the waiver of such milestone achievement by a majority vote of the respective series convertible preferred stockholders or in relation to the Series B convertible preferred stock, upon a shareholder exercising its right to early exercise the tranche right. The fair value of the tranche right liability was determined based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The fair value of the tranche right liabilities were determined using a Contingent Forward Analysis, which is a scenario-based lattice model that accounts for the different possible milestone scenarios and their associated probabilities, as estimated by the Company. The valuation model considered the probability of closing the tranche, the estimated future value of the Convertible Preferred Stock to be issued at each closing and the investment required at each closing. Future values were converted to present value using a discount rate appropriate for probability-adjusted cash flows. The risk-free rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining estimated time to each tranche closing.

Series A Preferred Stock Tranche Right Liability


	Series A Preferred Stock Tranche Right Liability
Balance as of December 31, 2022	$	10,435
Change in fair value of Series A preferred stock tranche right liability		1,030
Settlement of Series A preferred stock tranche right liability upon waiver of milestone		(11,465	)
Balance as of September 30, 2023	$	—

Series B Preferred Stock Tranche Right Liability


	Second Tranche Milestone
Probability of meeting Series B milestone		80	%
Milestone achievement date	12/31/2024
Risk-free rate		4.79	%
Expected value of Series B if milestones are not met	$	0.84


	Series B Preferred Stock Tranche Right Liability
Balance as of December 31, 2023	$	4,200
Change in fair value of Series B preferred stock tranche right liability		7,390
Settlement of Series B preferred stock tranche right liability upon waiver of milestone		(11,590	)
Balance as of September 30, 2024	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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-Section 55
-Paragraph 107
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-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

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+ Details

Net Loss per Share - Schedule of Basic and Diluted Net Loss Per Common Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss attributable to common stockholders	$ (17,537)	$ (8,709)	$ (58,327)	$ (21,267)
Denominator:
Weighted average common shares outstanding, basic	34,855,907	1,529,216	15,925,777	1,444,666
Weighted average common shares outstanding, diluted	34,855,907	1,529,216	15,925,777	1,444,666
Net loss per share attributable to common stockholders, basic	$ (0.5)	$ (5.7)	$ (3.66)	$ (14.72)
Net loss per share attributable to common stockholders, diluted	$ (0.5)	$ (5.7)	$ (3.66)	$ (14.72)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
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+ Details

Accrued Expenses and Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2024

Payables and Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Research and development	$	1,236	$	2,645
Professional fees		312		459
Employee related		3,230		2,413
Accrued other		278		114
	$	5,056	$	5,631

Property and Equipment, Net - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation expense of property and equipment	$ 200,000		$ 600,000
Maximum
Property, Plant and Equipment [Line Items]
Depreciation expense of property and equipment		$ 23,000		$ 59,000

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($)
$ in Thousands

Sep. 30, 2024

Dec. 31, 2023

Accrued Liabilities, Current [Abstract]

Research and development

$ 1,236

$ 2,645

Professional fees

312

459

Employee related

3,230

2,413

Accrued other

278

114

Accrued expenses and other current liabilities

^[1]

$ 5,056

$ 5,631

[1]	Includes related party amounts of zero and $0.2 million (accounts payable) and less than $0.1 million and zero (accrued expenses) as of September 30, 2024 and December 31, 2023, respectively (see Notes 5 and 10).

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (58,327)	$ (21,267)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	579	59
Net (accretion) and amortization of investments in marketable securities	(3,771)
Change in fair value of preferred stock tranche right liability	7,390	1,030
Non-cash lease expense	477	52
Stock-based compensation expense	7,027	2,527
Series A and B preferred stock issuance costs allocated to tranche right liabilities		67
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,842)	(1,315)
Other assets	51	(125)
Accounts payable	(994)	131
Accrued expenses and other current liabilities	(477)	2,003
Operating lease liabilities	(495)	14
Net cash used in operating activities	(50,382)	(16,824)
Cash flows from investing activities
Purchases of short-term investments	(292,973)
Maturities of short-term investments	93,081
Purchases of property and equipment	(2,179)	(199)
Net cash used in investing activities	(202,071)	(199)
Cash flows from financing activities
Proceeds from initial public offering and concurrent private placement, net of underwriter discounts and commissions and deferred offering costs	157,705
Proceeds from issuance restricted common stock		54
Repurchase of unvested restricted common stock		(4)
Net cash provided by financing activities	221,618	145,276
Net (decrease) increase in cash, cash equivalents, and restricted cash	(30,835)	128,253
Cash, cash equivalents, and restricted cash at beginning of period	70,254	31,159
Cash, cash equivalents, and restricted cash at end of period	39,419	159,412
Supplemental disclosure for noncash investing and financing activities:
Deferred offering costs included in accounts payable and accrued expenses at period end		(6)
Purchases of property and equipment included in accounts payable and accrued expenses at period end	17	208
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	39,314	159,412
Restricted cash	105
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	39,419	159,412
Series A Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs paid		59,920
Supplemental disclosure for noncash investing and financing activities:
Conversion of convertible preferred stock into common stock upon closing of initial public offering	89,487
Series B Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs paid	63,913	85,306
Supplemental disclosure for noncash investing and financing activities:
Conversion of convertible preferred stock into common stock upon closing of initial public offering	145,252
Series A Preferred Stock
Supplemental disclosure for noncash investing and financing activities:
Settlement of preferred stock tranche right liability		11,465
Series B Preferred Stock
Supplemental disclosure for noncash investing and financing activities:
Settlement of preferred stock tranche right liability	$ 11,590	$ 581

Property and Equipment, Net (Tables)

9 Months Ended

Sep. 30, 2024

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consisted of the following (in thousands):


	September 30, 2024			December 31, 2023
Lab equipment	$	3,691		$	1,719
Computer equipment		68			43
Leasehold improvements		281			255
Construction in process		74			26
Total property and equipment		4,114			2,043
Less: Accumulated depreciation		(705	)		(127	)
	$	3,409		$	1,916

Leases

9 Months Ended

Sep. 30, 2024

Leases [Abstract]

Leases

9. Leases

Operating Lease

In June 2023, the Company entered into a lease for its corporate headquarters in Boston, Massachusetts. The lease commenced August 31, 2023 with an initial term of 40 months. The monthly lease payments are $66 thousand for the first 12 months, with 2% escalation each year. In conjunction with the lease, the Company paid a security deposit of $0.1 million that is recorded on the Company’s condensed consolidated balance sheet in other assets as of September 30, 2024.

In February 2024, the Company entered into a lease for laboratory and office space in San Diego, California with a lease term of 5 years for which the Company expects to pay $9.6 million over the lease term. Per the terms of the lease, the landlord will deliver the space to the Company on the lease Commencement date, which is no earlier than November 2024. As of September 30, 2024, the Company has not yet occupied the lease space and therefore, the Company has not recorded a corresponding right-of-use asset or liability on the condensed consolidated balance sheet as of September 30, 2024.

Net Loss per Share (Tables)

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss Per Common Share Attributable to Common Stockholders

Basic and diluted net loss per common share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Numerator:
Net loss attributable to common stockholders	$	(17,537	)	$	(8,709	)	$	(58,327	)	$	(21,267	)
Denominator:
Weighted average common shares outstanding, basic and diluted		34,855,907			1,529,216			15,925,777			1,444,666
Net loss per share attributable to common stockholders, basic and diluted	$	(0.50	)	$	(5.70	)	$	(3.66	)	$	(14.72	)

Schedule of Potential Common Shares Excluded from Computation of Diluted Net Loss Per Share Available to Common Shareholders


	As of September 30,
	2024		2023
Series A convertible preferred stock		—		100,182,354
Series B convertible preferred stock		—		51,273,790
Options to purchase common stock		3,998,325		—
Unvested restricted common stock—service based		1,115,054		1,943,797
Unvested restricted common stock—performance based		495,491		700,526

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical)
$ in Thousands

9 Months Ended

Sep. 30, 2024

USD ($)

Research and development

$ 43,736

^[1]

General and administrative

15,798

^[2]

Third Rock Ventures LLC

General and administrative

100

Third Rock Ventures LLC | Maximum

Research and development

$ 100

[1]	Includes related party amounts of zero for each of the three months ended September 30, 2024 and 2023, and less than $0.1 million and $0.5 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).
[2]	Includes related party amounts of zero and $0.2 million for the three months ended September 30, 2024 and 2023, respectively and $0.1 million and $0.7 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Common Stock

9 Months Ended

Sep. 30, 2024

Stockholders' Equity Note [Abstract]

Common Stock

7. Common Stock

The voting, dividend and liquidation rights of the holders of the Company’s common stock were subject to and qualified by the rights, powers and preferences of the holders of the convertible preferred stock set forth above. Each share of common stock entitles the holder to one vote, together with the holders of the convertible preferred stock, on all matters submitted to the stockholders for a vote. The holders of common stock are entitled to receive dividends, if any, as declared by the Company’s board of directors, subject to the preferential dividend rights of convertible preferred stock. As of September 30, 2024 and December 31, 2023, no dividends have been declared or paid.

On May 30, 2024, the Company’s stockholders approved the third amended and restated certificate of incorporation, which was filed upon the closing of the IPO on June 10, 2024 and which, among other things, increased the number of shares of common stock authorized for issuance from 250,000,000 to 500,000,000 shares of common stock.

In June 2024, the Company completed its IPO of its common stock. In connection with its IPO, the Company issued and sold 9,200,000 shares of its common stock at a price of $17.00 per share. As a result, the Company received $140.9 million in net proceeds, after deducting underwriting discounts and commissions and offering costs of $15.5 million.

In connection with its IPO, the Company issued and sold 1,058,824 shares of its common stock in a concurrent private placement, at a price of $17.00 per share, and received $16.7 million in net proceeds, after deducting placement agent fees and other private placement costs of $1.3 million.

As of December 31, 2023, the Company had reserved 23,890,096 shares of common stock, of which 22,146,816 were reserved for the potential conversion of shares of Series A convertible preferred stock and Series B convertible preferred stock, and 1,743,280 shares for issuance under the Company’s 2022 Stock Option and Grant Plan, as amended (the “2022 Plan”). The Series A convertible preferred stock and Series B convertible preferred stock were converted to common stock immediately prior to completion of the IPO. As of September 30, 2024, the Company had reserved 6,885,232 shares of common stock, of which 2,746,371 shares were reserved for issuance under the 2022 Plan, 3,814,618 shares under the 2024 Stock Option and Grant Plan (the “2024 Plan”) and 324,243 shares under the 2024 Employee Stock Purchase Plan (the “2024 ESPP”) (see Note 8).

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
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-Publisher FASB
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+ Details

Nature of the Business and Basis of Presentation

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Rapport Therapeutics, Inc., together with its consolidated subsidiary (the “Company”) is a clinical-stage biopharmaceutical company focused on discovery and development of transformational small molecule medicines for patients suffering from central nervous system disorders. The Company was incorporated in the state of Delaware in February 2022 as Precision Neuroscience NewCo, Inc. In October 2022, the Company changed its name to Rapport Therapeutics, Inc. The Company is located in Boston, Massachusetts and San Diego, California.

The Company is subject to risks and uncertainties common to early stage companies in the biotechnology industry, including, but not limited to, completing preclinical studies and clinical trials, obtaining regulatory approval for product candidates, market acceptance of products, development by competitors of new technological innovations, dependence on key personnel, the ability to attract and retain qualified employees, reliance on third-party organizations, protection of proprietary technology, compliance with government regulations, and the ability to raise additional capital to fund operations. The Company’s product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure, and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Reverse stock split

On May 31, 2024, the Company effected a one-for-8.5648 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios of each series of the Company’s preferred stock (see Note 6). Accordingly, all share and per share amounts for all periods presented in the accompanying condensed consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustment of the preferred stock conversion ratio.

Liquidity

The accompanying condensed consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred recurring losses since its inception, including net losses of $58.3 million and $34.8 million for the nine months ended September 30, 2024 and for the year ended December 31, 2023, respectively. As of September 30, 2024, the Company had an accumulated deficit of $103.8 million. In June 2024, the Company completed its initial public offering (“IPO”) and concurrent private placement of its common stock which resulted in net proceeds of $157.6 million. The Company had cash and cash equivalents and short-term investments, excluding restricted cash, of $320.7 million as of September 30, 2024. The Company expects to continue to generate operating losses for the foreseeable future. The Company expects that its cash and cash equivalents and short-term investments will be sufficient to fund its operating expenses and capital expenditure requirements through at least 12 months from the issuance of these condensed consolidated financial statements.

The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations though equity offerings, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain funding on acceptable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders.

The inability to raise capital as and when needed would have a negative impact on the Company’s financial condition and its ability to pursue its business strategy. The company will need to generate significant revenue to achieve profitability, and it may never do so.

If the Company is unable to obtain funding, it could be forced to delay, reduce or eliminate some or all of its research and development programs, which could adversely affect its business prospects, or it may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared by the Company in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. The accompanying unaudited condensed consolidated financial statements reflect the operations of the Company. Intercompany balances and transactions have been eliminated in consolidation. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).

The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position as of September 30, 2024 and the results of operations for the three and nine months ended September 30, 2024 and 2023.The condensed consolidated balance sheet as of December 31, 2023 was derived from audited annual financial statements but does not include all disclosures required by GAAP. The results of operations for the interim periods are not necessarily indicative of results to be expected for the year ending December 31, 2024, any other interim periods, or any future year or period.