0000950170-24-123291 | 10-Q | XBRL Viewer

Accounts Payable and Accrued Liabilities

9 Months Ended

Sep. 30, 2024

Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Accounts payable	$	2,542	$	2,222
Accrued research and development costs		3,427		1,575
Other accrued liabilities		1,072		469
Total accounts payable and accrued liabilities	$	7,041	$	4,266

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Summary of Financial Assets Measured at Fair Value on Recurring Basis

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis and their respective input levels based on the fair value hierarchy described in Note 2 above (in thousands):


			Fair Value Measurements Using
As of September 30, 2024	Amount		Level 1		Level 2		Level 3
Assets
Money market funds (1)	$	28,991	$	28,991	$	—	$	—
U.S. government obligations (2)		125,980		—		125,980		—
Corporate debt securities (2)		8,399		—		8,399		—
Total fair value of assets	$	163,370	$	28,991	$	134,379	$	—

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.


			Fair Value Measurements Using
As of December 31, 2023	Amount		Level 1		Level 2		Level 3
Assets
Money market funds (1)	$	21,737	$	21,737	$	—	$	—
U.S. government obligations (2)		92,143		—		92,143		—
Corporate debt securities (2)		4,903		—		4,903		—
Total fair value of assets	$	118,783	$	21,737	$	97,046	$	—

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.

Condensed Statements of Convertible Preferred Stock and Stockholders' Equity/(Deficit) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Issuance of common stock, net discounts and offering costs	$ 12,305
Series C Convertible Preferred Stock
Net of issuance costs		$ 329

Net Loss Per Common Share

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Net Loss Per Common Share

12.

Net Loss Per Common Share

The following table summarizes the calculation of basic and diluted net loss per common share attributable to common stockholders (in thousands, except per share data):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Net loss	$	(16,509	)	$	(13,173	)	$	(48,915	)	$	(37,290	)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted		22,254			1,230			15,204			1,207
Net loss per share, basic and diluted	$	(0.74	)	$	(10.71	)	$	(3.22	)	$	(30.89	)

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


	September 30,
	2024		2023
Conversion of outstanding convertible preferred stock		—		14,740,840
Options to purchase common stock		4,240,477		2,688,005
Options early exercised subject to future vesting		72		2,005
Total		4,240,549		17,430,850

Fair Value Measurements - Additional Information (Details) - USD ($)	Sep. 30, 2024	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair value assets transfer between levels	$ 0	$ 0

Convertible Preferred Stock	9 Months Ended
Sep. 30, 2024
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	9. Convertible Preferred Stock Series A, B, and C Convertible Preferred Stock The Company issued its previously outstanding convertible preferred stock in a series of transactions as follows: • In August 2018, 7,142,857 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $4.9 million; • In June 2019, an additional 26,046,438 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $18.1 million; • In July 2020, an additional 33,189,295 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $23.2 million; • In April 2021, 78,211,116 shares of Series B convertible preferred stock were issued for cash at a price of $1.35 per share, resulting in aggregate net proceeds of $105.3 million; • In April and May 2023, 142,857,138 shares of Series C convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $99.7 million. Common Stock Issued for Conversion of Convertible Preferred Stock Immediately prior to the closing of the IPO on April 2, 2024, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock, as adjusted for the reverse stock split. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding. Rights, Preferences, and Privileges of Convertible Preferred Stock The rights, preferences, and privileges of the previously outstanding convertible preferred stock are detailed in Note 9 of the notes to financial statements included in the Prospectus.

Convertible Preferred Stock

9 Months Ended

Sep. 30, 2024

Temporary Equity Disclosure [Abstract]

Convertible Preferred Stock

Series A, B, and C Convertible Preferred Stock

The Company issued its previously outstanding convertible preferred stock in a series of transactions as follows:

•

In August 2018, 7,142,857 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $4.9 million;

•

In June 2019, an additional 26,046,438 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $18.1 million;

•

In July 2020, an additional 33,189,295 shares of Series A convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $23.2 million;

•

In April 2021, 78,211,116 shares of Series B convertible preferred stock were issued for cash at a price of $1.35 per share, resulting in aggregate net proceeds of $105.3 million;

•

In April and May 2023, 142,857,138 shares of Series C convertible preferred stock were issued for cash at a price of $0.70 per share, resulting in aggregate net proceeds of $99.7 million.

Common Stock Issued for Conversion of Convertible Preferred Stock

Immediately prior to the closing of the IPO on April 2, 2024, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock, as adjusted for the reverse stock split. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding.

Rights, Preferences, and Privileges of Convertible Preferred Stock

The rights, preferences, and privileges of the previously outstanding convertible preferred stock are detailed in Note 9 of the notes to financial statements included in the Prospectus.

Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				2 Months Ended	9 Months Ended
	Apr. 30, 2021	Jul. 31, 2020	Jun. 30, 2019	Aug. 31, 2018	May 31, 2023	Sep. 30, 2023	Sep. 30, 2024	Apr. 02, 2024	Dec. 31, 2023
Temporary Equity [Line Items]
Convertible preferred stock, shares issued							0		287,446,844
Convertible preferred stock, par value							$ 0.0001		$ 0.0001
Aggregate net proceeds from issuance of convertible preferred stock						$ 100,000
IPO
Temporary Equity [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion								14,740,840
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Convertible preferred stock, shares issued		33,189,295	26,046,438	7,142,857
Convertible preferred stock, par value		$ 0.7	$ 0.7	$ 0.7
Aggregate net proceeds from issuance of convertible preferred stock		$ 23,200	$ 18,100	$ 4,900
Series B Convertible Preferred Stock
Temporary Equity [Line Items]
Convertible preferred stock, shares issued	78,211,116
Convertible preferred stock, par value	$ 1.35
Aggregate net proceeds from issuance of convertible preferred stock	$ 105,300
Series C Convertible Preferred Stock
Temporary Equity [Line Items]
Convertible preferred stock, shares issued					142,857,138
Convertible preferred stock, par value					$ 0.7
Aggregate net proceeds from issuance of convertible preferred stock					$ 99,700

Property and Equipment

9 Months Ended

Sep. 30, 2024

Property, Plant and Equipment [Abstract]

Property and Equipment

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


	September 30,		December 31,
	2024		2023
Lab equipment	$	4,346	$	4,264
Computers and software		853		833
Leasehold improvements		697		46
Furniture and fixtures		1,580		157
Total property and equipment		7,476		5,300
Less accumulated depreciation and amortization		3,517		2,727
Property and equipment, net	$	3,959	$	2,573

Depreciation and amortization expense related to property and equipment was $0.3 million and $0.8 million for the three and nine months ended September 30, 2024, respectively, and $0.2 million and $0.7 million for the three and nine months ended September 30, 2023, respectively.

Net Loss Per Common Share (Tables)

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Summary of Basic and Diluted Net Loss Per Common Share

The following table summarizes the calculation of basic and diluted net loss per common share attributable to common stockholders (in thousands, except per share data):


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Net loss	$	(16,509	)	$	(13,173	)	$	(48,915	)	$	(37,290	)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted		22,254			1,230			15,204			1,207
Net loss per share, basic and diluted	$	(0.74	)	$	(10.71	)	$	(3.22	)	$	(30.89	)

Summary of Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share


	September 30,
	2024		2023
Conversion of outstanding convertible preferred stock		—		14,740,840
Options to purchase common stock		4,240,477		2,688,005
Options early exercised subject to future vesting		72		2,005
Total		4,240,549		17,430,850

Accounts Payable and Accrued Liabilities (Tables)

9 Months Ended

Sep. 30, 2024

Payables and Accruals [Abstract]

Schedule of Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities consisted of the following (in thousands):


	September 30, 2024		December 31, 2023
Accounts payable	$	2,542	$	2,222
Accrued research and development costs		3,427		1,575
Other accrued liabilities		1,072		469
Total accounts payable and accrued liabilities	$	7,041	$	4,266

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Rule 10b5-1 Trading Arrangements From time to time, our officers (as defined in Rule 16a-1(f) of the Exchange Act) and directors may enter into or terminate Rule 10b5-1 trading arrangements or non-Rule 10b5-1 trading arrangements (as each such term is defined in Item 408 of Regulation S-K). During the three months ended September 30, 2024, no officer or director adopted, modified, or terminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement.
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

Stock Options and Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2024	Mar. 31, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Apr. 02, 2024	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options to purchase shares of common stock			4,240,477		4,240,477			2,813,937
Increamental non cash stock based compensation			$ 857,000		$ 857,000
Intrinsic value of options exercised			0	$ 4,000	32,000	$ 15,000
Unrecognized compensation cost related to outstanding time-based options			$ 20,100,000		$ 20,100,000
Unrecognized compensation cost expected to be recognized over a weighted-average period					2 years 8 months 12 days
Weighted-average grant date per share fair value of options granted			$ 7.25	$ 3.23	$ 7.2	$ 5.8
Common stock reserved for future issuance			6,699,612		6,699,612			18,415,932
Stock-based compensation			$ 2,045,000	$ 883,000	$ 5,508,000	$ 2,425,000
Common stock, shares authorized			700,000,000		700,000,000		700,000,000	402,600,000
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost related to outstanding time-based options			$ 700,000		$ 700,000
Unrecognized compensation cost expected to be recognized over a weighted-average period					1 year 3 months 14 days
Offering period		24 months
Purchase period		6 months
Percentage of fair market value of common stock purchase price		85.00%
Common stock reserved for future issuance		231,919
Stock-based compensation			100,000	$ 0	$ 300,000	$ 0
Share-based payment arrangement, withheld on behalf of employees for future purchases			$ 200,000		$ 200,000
Shares issued under ESPP			0	0	0	0
Percentage of outstanding common stock maximum		1.00%
Repriced Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Exercise price	$ 3.56
Increamental non cash stock based compensation			$ 157,000		$ 157,000
Increamental non cash stock based compensation expense related unvested repriced options					700,000
Repriced Options \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options to purchase shares of common stock	3,484,346
General and Administrative Expense and Research and Development Expense \| Repriced Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Increamental non cash stock based compensation expense related unvested repriced options			$ 34,000		$ 34,000
2024 Incentive Award Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Term of the plan		10 years
Percentage of excise price		100.00%
Number of shares authorized for issuance			2,832,714		2,832,714
Number of shares remained available for grant			2,227,216		2,227,216
Percentage of outstanding common stock maximum		5.00%
2024 Incentive Award Plan \| Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expiration period		10 years
2024 Incentive Award Plan \| Employee Stock Option \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		36 months
2024 Incentive Award Plan \| Employee Stock Option \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		48 months

Investments - Schedule of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Acquisition Cost	$ 163,134	$ 118,743
Unrealized Gain	236	63
Unrealized Loss		(23)
Estimated Fair Value	163,370	118,783
Short-term Investments
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value	126,921	97,046
U.S. Government Obligations
Debt Securities, Available-for-Sale [Line Items]
Acquisition Cost	125,751	92,106
Unrealized Gain	229	58
Unrealized Loss		(21)
Estimated Fair Value	125,980	92,143
Corporate Debt Securities
Debt Securities, Available-for-Sale [Line Items]
Acquisition Cost	8,392	4,900
Unrealized Gain	7	5
Unrealized Loss		(2)
Estimated Fair Value	8,399	4,903
Cash Equivalents
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Value	36,449	21,737
Money Market Funds
Debt Securities, Available-for-Sale [Line Items]
Acquisition Cost	28,991	21,737
Estimated Fair Value	$ 28,991	$ 21,737

Common Stock - Additional Information (Details)	9 Months Ended
Common Stock - Additional Information (Details)	Sep. 30, 2024 Vote
Subsidiary, Sale of Stock [Line Items]
Common stock, voting rights	The holder of each outstanding share of common stock is entitled to one vote on all matters submitted to a vote of the holders of common stock.
Number of vote	1

Common Stock (Tables)

9 Months Ended

Sep. 30, 2024

Equity [Abstract]

Schedule of Common Stock Reserved For Future Issuance

Common stock reserved for future issuance consisted of the following:


	As of September 30,		As of December 31,
	2024		2023
Conversion of outstanding convertible preferred stock		—		14,740,840
Common stock options issued and outstanding		4,240,477		2,813,937
Equity awards available for future issuance		2,227,216		861,155
Shares available for purchase under the ESPP		231,919		—
Total		6,699,612		18,415,932

Fair Value Measurements

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurements


			Fair Value Measurements Using
As of September 30, 2024	Amount		Level 1		Level 2		Level 3
Assets
Money market funds (1)	$	28,991	$	28,991	$	—	$	—
U.S. government obligations (2)		125,980		—		125,980		—
Corporate debt securities (2)		8,399		—		8,399		—
Total fair value of assets	$	163,370	$	28,991	$	134,379	$	—

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.


			Fair Value Measurements Using
As of December 31, 2023	Amount		Level 1		Level 2		Level 3
Assets
Money market funds (1)	$	21,737	$	21,737	$	—	$	—
U.S. government obligations (2)		92,143		—		92,143		—
Corporate debt securities (2)		4,903		—		4,903		—
Total fair value of assets	$	118,783	$	21,737	$	97,046	$	—

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.

The Company’s money market funds are classified as Level 1 because they are valued using quoted market prices in active markets for identical assets. The Company’s investments consist of available-for-sale securities and are classified as Level 2 because their value is based on valuations using significant inputs derived from or corroborated by observable market data.

There were no transfers of assets between fair value levels for any period presented.

- 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
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 107
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-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/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 940
-SubTopic 820
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478119/940-820-50-1

+ Details

Organization and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands			3 Months Ended	9 Months Ended
	Apr. 02, 2024 USD ($) $ / shares shares	Mar. 19, 2024	Jun. 30, 2024 shares	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Entity Incorporation, State or Country Code				DE
Net proceeds \| $				$ 93,000
Common stock, shares authorized	700,000,000			700,000,000	402,600,000
Common stock, par value \| $ / shares	$ 0.0001			$ 0.0001	$ 0.0001
Preferred stock, shares authorized	70,000,000			70,000,000	0
Preferred stock, par value \| $ / shares	$ 0.0001			$ 0.0001	$ 0.0001
Reverse stock split, description				On March 19, 2024, the Company effected a one-for-19.5 reverse stock split of its issued and outstanding shares of common stock.
Reverse stock split ratio		0.05
Accumulated deficit \| $				$ (185,024)	$ (136,109)
Cash, cash equivalents, and short-term investments \| $				$ 167,100
Common Stock
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares sold			6,250,000
IPO
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares sold	6,250,000
Share price \| $ / shares	$ 16
Net proceeds \| $	$ 87,700
Convertible preferred stock converted into common stock	14,740,840

Net Loss Per Common Share - Summary of Basic and Diluted Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Net loss	$ (16,509)	$ (13,173)	$ (48,915)	$ (37,290)
Weighted-average shares of common stock used in computing net loss per share, basic	22,254	1,230	15,204	1,207
Weighted-average shares of common stock used in computing net loss per share, diluted	22,254	1,230	15,204	1,207
Net loss per share - basic	$ (0.74)	$ (10.71)	$ (3.22)	$ (30.89)
Net loss per share - diluted	$ (0.74)	$ (10.71)	$ (3.22)	$ (30.89)

- 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

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
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 60
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476176/805-60-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 323
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478666/740-323-65-2

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481687/323-10-50-3

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-28

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482765/220-10-50-6

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480175/815-40-65-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-8

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-11

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-11

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483443/250-10-50-4

Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479168/946-830-55-10

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479105/946-220-45-7

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-3

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-60B

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-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

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events In November 2024, the 2024 Lease commenced and the Company recorded an ROU asset of $45.8 million and a related lease liability of $45.3 million. For additional information, see Note 7 above.

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.0001	$ 0.0001
Convertible preferred stock, liquidation preference		$ 252.1
Convertible preferred stock, shares authorized	0	287,446,844
Convertible preferred stock, shares issued	0	287,446,844
Convertible preferred stock, shares outstanding	0	287,446,844
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	70,000,000	0
Preferred stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	700,000,000	402,600,000
Common stock shares issued	22,254,537	1,248,493
Common stock, shares outstanding	22,254,465	1,247,012

Condensed Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ 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	$ 14,089	$ 11,645	$ 41,953	$ 32,223
General and administrative	4,626	3,308	13,036	8,777
Total operating expenses	18,715	14,953	54,989	41,000
Loss from operations	(18,715)	(14,953)	(54,989)	(41,000)
Other income, net:
Interest income	2,174	1,748	5,977	3,662
Other income, net	32	32	97	48
Total other income, net	2,206	1,780	6,074	3,710
Net loss	(16,509)	(13,173)	(48,915)	(37,290)
Comprehensive loss:
Net Income (Loss)	(16,509)	(13,173)	(48,915)	(37,290)
Unrealized gain on short-term investments	300	26	196	284
Comprehensive loss	$ (16,209)	$ (13,147)	$ (48,719)	$ (37,006)
Net loss per share - basic	$ (0.74)	$ (10.71)	$ (3.22)	$ (30.89)
Net loss per share - diluted	$ (0.74)	$ (10.71)	$ (3.22)	$ (30.89)
Shares used in calculation, basic	22,254	1,230	15,204	1,207
Shares used in calculation, diluted	22,254	1,230	15,204	1,207

Stock Options and Stock-Based Compensation - Schedule of Excluding Any Effect of the Option Repricing, Weighted-average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Stock Options Granted (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Expected option life (in years)	6 years	6 years 1 month 6 days	6 years	6 years
Assumed volatility	90.80%	95.70%	90.90%	92.20%
Assumed risk-free interest rate	3.80%	3.90%	3.90%	3.90%

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) Segment	Apr. 02, 2024 shares	Dec. 31, 2023 USD ($)
Summary of Significant Accounting Policies [Line Items]
Increase in federally insured limits	$ 3,400
Deferred offering costs	$ 0		$ 2,200
Number of operating segments \| Segment	1
IPO
Summary of Significant Accounting Policies [Line Items]
Convertible preferred stock converted into common stock \| shares		14,740,840

Property and Equipment - Summary 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	$ 7,476	$ 5,300
Less accumulated depreciation and amortization	3,517	2,727
Property and equipment, net	3,959	2,573
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	4,346	4,264
Computers and software
Property, Plant and Equipment [Line Items]
Total property and equipment	853	833
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	697	46
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,580	$ 157

Subsequent Events - Additional Information (Details) - USD ($) $ in Thousands	Nov. 07, 2024	Sep. 30, 2024	Dec. 31, 2023
Subsequent Event [Line Items]
ROU asset		$ 109	$ 2,002
2022 Lease
Subsequent Event [Line Items]
ROU asset		100
Lease liability		$ 100
2024 Lease \| Subsequent Event
Subsequent Event [Line Items]
ROU asset	$ 45,800
Lease liability	$ 45,300

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2024	Nov. 06, 2024
Cover [Abstract]
Amendment Flag	false
Entity Central Index Key	0001782303
Current Fiscal Year End Date	--12-31
Document Type	10-Q
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Entity Registrant Name	BOUNDLESS BIO, INC.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-41989
Entity Tax Identification Number	83-0751369
Entity Address, Address Line One	9880 Campus Point Drive
Entity Address, Address Line Two	Suite 120
Entity Address, City or Town	San Diego
Entity Address, Postal Zip Code	92121
Entity Address, State or Province	CA
City Area Code	(858)
Local Phone Number	766-9912
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	BOLD
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		22,300,043
Document Transition Report	false
Document Quarterly Report	true

Stock Options and Stock-Based Compensation

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

Stock Options and Stock-Based Compensation

11.

Stock Options and Stock-Based Compensation

Equity Incentive Plan

In March 2024, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2024 Incentive Award Plan (the Plan), which became effective in connection with the IPO and has a term of ten years. The Plan provides for the grant of incentive stock options, nonqualified stock options, restricted stock, dividend equivalents, restricted stock units, stock appreciation rights, and other stock or cash-based awards to the Company's employees, consultants, and directors. Options granted under the Plan are exercisable at various dates as determined upon grant and will expire no more than 10 years from their date of grant. Stock options generally vest over terms of either 36 or 48 months. The exercise price of awards granted under the Plan shall not be less than 100% of the estimated fair market value of the Company’s common stock on the date of grant. In addition, the Plan includes an “evergreen” provision whereby the number of shares of common stock available for issuance under the Plan will be increased annually on the first day of each calendar year during the term of the Plan, beginning in 2025, by an amount equal to the lesser of (i) 5% of the shares of common stock outstanding on the final day of the immediately preceding calendar year or (ii) such number of shares as determined by the Company’s board of directors or an authorized committee of the board of directors. As of September 30, 2024, a total of 2,832,714 shares of common stock were authorized for issuance under the Plan. On September 30, 2024, 2,227,216 of these shares were available for grant under the Plan.

Prior to the adoption of the Plan, the Company had awarded common stock options under the 2018 Equity Incentive Plan (as amended, the Predecessor Plan). Under the provisions of the Plan, the shares subject to awards issued under the Predecessor Plan that were outstanding as of March 27, 2024, the effective date of the Plan, and that are subsequently cancelled or forfeited, will become available for issuance under, and will increase the number of shares that may be issued under, the Plan.

Repricing of Outstanding Options

In August 2024, the compensation committee of the Company’s board of directors, as administrator of the Plan and the Predecessor Plan, approved an option repricing, which was effective on August 19, 2024 (the Effective Date). The repricing applied to options to purchase up to an aggregate of 3,484,346 shares of the Company’s common stock with an exercise price per share in excess of the closing price per share of the Company’s common stock on the Effective Date, held by eligible employees of the Company that were granted under the Plan or the Predecessor Plan and were outstanding as of the Effective Date (the Repriced Options). As of the Effective Date, the exercise price of each of the Repriced Options was reduced to $3.56 per share, which was the closing price of the Company’s common stock on the Effective Date; provided, however, that if prior to the Premium End Date (as defined below), a Repriced Option is exercised or an employee’s employment or service with the Company terminates for any reason other than due to a Qualifying Termination (as defined below), the exercise price per share that applied to the Repriced Option immediately prior to the Effective Date will apply in lieu of the reduced exercise price. The “Premium End Date” means the earliest of: (1) August 19, 2026, (2) the date immediately prior to the closing of a Change in Control (as defined in the Plan), or (3) the date of the employee’s Qualifying Termination. A “Qualifying Termination” means (a) the involuntary termination of the employee’s employment by the Company due to a reduction in force (and other than for Cause (as defined in the Plan)), subject to the employee’s execution of an effective general release of claims in favor of the Company, (b) the employee’s death, or (c) termination of the employee’s employment by the Company following the employee’s Disability (as defined in the Plan). Except for the reduction in the exercise prices of the Repriced Options as described above, the Repriced Options retain their existing terms, including their respective original vesting schedules.

The repricing resulted in a total incremental non-cash stock-based compensation expense of $857,000, which was calculated using the Black-Scholes option-pricing model, of which $157,000 is associated with vested Repriced Options and will be recognized on a straight-line basis through the Premium End Date. The remaining $700,000 of the incremental non-cash stock-based compensation expense is associated with unvested Repriced Options and will be recognized as follows: (i) if the Premium End Date occurs later than the end of the remaining vesting period of the Repriced Option, the incremental cost will be amortized on a straight-line basis through

the Premium End Date, or (ii) if the Premium End Date occurs earlier than the end of the remaining vesting period of the Repriced Option, the incremental cost will be amortized on a straight-line basis over the remaining vesting period.

During both the three and nine months ended September 30, 2024, the Company recognized incremental stock-based compensation expense totaling $34,000 associated with the repricing, which is included in general and administrative expense and research and development expense on the condensed statement of operations and comprehensive loss.

Stock Options

Stock option activity under the Plan and certain other related information is as follows:


	Number			Weighted- Average Exercise Price		Weighted- Average Remaining Term (years)		Aggregate- Intrinsic Value (in 000’s)
Balance as of December 31, 2023		2,813,937		$	4.10		7.8	$	562
Granted		4,973,990		$	7.71
Exercised		(15,211	)	$	3.90
Forfeited and expired		(3,532,239	)	$	6.42
Balance as of September 30, 2024		4,240,477		$	6.42		8.4	$	75
Vested and expected to vest at September 30, 2024		4,240,477		$	6.42		8.4	$	75
Exercisable as of September 30, 2024		1,653,773		$	4.90		7.4	$	75

Aggregate intrinsic value in the above table is the difference between the estimated fair value of the Company’s common stock as of either September 30, 2024 or December 31, 2023, and the exercise price of stock options that had exercise prices below that value. For the Repriced Options, the calculation of the weighted-average prices and intrinsic value information in the table above is based on the exercise price per share that applied immediately prior to the Effective Date of the repricing pending satisfaction of the requisite service requirement.

The options exercised during the three and nine months ended September 30, 2024 had an intrinsic value at exercise of approximately $0 and $32,000, respectively. The options exercised during the three and nine months ended September 30, 2023 had an intrinsic value at exercise of approximately $4,000 and $15,000, respectively.

Stock-Based Compensation Expense

Stock-based compensation expense was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Research and development expenses	$	801	$	378	$	2,214	$	1,045
General and administrative expenses		1,244		505		3,294		1,380
Total stock-based compensation	$	2,045	$	883	$	5,508	$	2,425

As of September 30, 2024, unrecognized compensation cost related to outstanding time-based options was $20.1 million, which is expected to be recognized over a weighted-average period of 2.7 years.

Excluding any effect of the option repricing, the weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock options granted during the periods indicated in the table were as follows:


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Expected option life (in years)		6.0			6.1			6.0			6.0
Assumed volatility		90.8	%		95.7	%		90.9	%		92.2	%
Assumed risk-free interest rate		3.8	%		3.9	%		3.9	%		3.9	%
Expected dividend yield		—			—			—			—

Excluding any effect due to the option repricing, the weighted-average grant date per share fair value of options granted during the three months ended September 30, 2024 and 2023 was $7.25 and $3.23, respectively. The weighted-average grant date per share fair value of options granted during the nine months ended September 30, 2024 and 2023 was $7.20 and $5.80, respectively.

Employee Stock Purchase Plan

In March 2024, the Company’s board of directors adopted, and the Company’s stockholders approved, the Company’s 2024 Employee Stock Purchase Plan (the ESPP), which became effective in connection with the IPO. The ESPP permits participants to contribute up to a specified percentage of their eligible compensation during a series of offering periods of 24 months, each comprised of four six-month purchase periods, to purchase shares of the Company’s common stock. The purchase price of the shares will be 85% of the fair market value of the Company’s common stock on the first day of trading of the applicable offering period or on the applicable purchase date, whichever is lower. A total of 231,919 shares of common stock were initially reserved for issuance under the ESPP. In addition, the ESPP includes an “evergreen” provision whereby the number of shares of common stock available for issuance under the ESPP will be increased annually on the first day of each calendar year during the term of the ESPP, beginning in 2025, by an amount equal to the lesser of (i) 1% of the shares of common stock outstanding on the final day of the immediately preceding calendar year or (ii) such number of shares as determined by the Company’s board of directors or an authorized committee of the board of directors. The Company recognized stock-based compensation expense related to the ESPP of $0.1 million and $0.3 million during the three and nine month periods ended September 30, 2024, respectively, and $0 during each of the three and nine months ended September 30, 2023. As of September 30, 2024, the unrecognized compensation cost related to the ESPP was $0.7 million and is expected to be recognized as expense over approximately 1.29 years. As of September 30, 2024, $0.2 million has been withheld on behalf of employees for future purchases under the ESPP and is included in accrued compensation on the condensed balance sheets. The Company did not issue or sell any shares under the ESPP during either of the three or nine months ended September 30, 2024 and 2023.

Lease Agreements

9 Months Ended

Sep. 30, 2024

Leases [Abstract]

Lease Agreements

2022 Lease

In March 2021, the Company entered into a non-cancelable operating lease for a facility in San Diego, California, which was amended in November 2021 (as amended, the 2022 Lease). The 2022 Lease had an initial term that ended in May 2024, which was amended such that the term now ends on the date occurring 14 days after the lease commencement date for the 2024 Lease (see below). The 2022 Lease provides for the rental of lab and office space, contains rent escalation provisions, and requires the Company to pay a portion of the operating costs related to the underlying multitenant facility. Rental payments under the 2022 Lease commenced in mid-January 2022. Based on information obtained from its landlord, the Company has recorded a right-of-use (ROU) asset and an associated lease obligation for the lab and office space leased under the 2022 Lease. The net ROU asset of $0.1 million and associated lease obligation of $0.1 million are reflected in the Company’s balance sheet as of September 30, 2024 and are estimates that will change should there be a change in the anticipated occupancy date of the property and associated campus underlying the 2024 Lease. The Company’s estimated incremental borrowing rate of approximately 8.0% was used in its present value calculation as the 2022 Lease does not have a stated rate and the implicit rate was not readily determinable.

The Company paid $2.1 million in cash for operating lease liabilities under the 2022 Lease, which is included in the operating activities section of the condensed statements of cash flows, during each of the nine-month periods ended September 30, 2024 and 2023. As of September 30, 2024, future minimum lease payments under the 2022 Lease are expected to total $0.1 million. All future payments under the 2022 Lease are expected to occur in 2024.

2024 Lease

In December 2021, the Company entered into a non-cancelable facility lease for approximately 80,000 square feet of lab and office space in La Jolla, California (the 2024 Lease). The facility to be occupied by the Company under the 2024 Lease will be built to the Company’s specifications; the 2024 Lease includes tenant improvement allowances totaling $22.0 million, repayment of which is included in the future minimum lease payments called for thereunder.

As of September 30, 2024, although construction of the property underlying the 2024 Lease was underway, the commencement date of the 2024 Lease had not yet been determined. The 2024 Lease has a 120-month term from the lease commencement date, with payments under the lease commencing after a six-month rent abatement period and continuing through the conclusion of the term. As of September 30, 2024, the landlord had advised the Company that this property would be available for occupancy in November 2024. For additional information, see Note 13. The 2024 Lease includes base lease payments totaling $71.9 million, as well as additional payment obligations for common area maintenance and property taxes. The Company has the right to extend the term of the 2024 Lease for an additional 60 months.

The Company made an upfront payment under the 2024 Lease of $0.5 million, which is included in prepaid expenses and other current assets on the balance sheet as of September 30, 2024 and December 31, 2023. Additionally, as a security deposit under the 2024 Lease, the Company is required to maintain a standby letter-of-credit in the amount of $0.5 million, which must remain in place until November 2034.

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Accounting Policies [Abstract]
Unaudited Condensed Interim Financial Information	Unaudited Condensed Interim Financial Information The condensed balance sheet as of September 30, 2024, the condensed statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023, the condensed statements of convertible preferred stock and stockholders’ equity / (deficit) for the three and nine months ended September 30, 2024 and 2023, and the condensed statements of cash flows for the nine months ended September 30, 2024 and 2023 are unaudited. These unaudited condensed financial statements have been prepared on the same basis as the Company's annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary to present fairly the Company’s financial position, results of operations, and cash flows for the interim period presented. The financial data and the other financial information contained in these notes to the condensed financial statements related to the three and nine months ended September 30, 2024 and 2023 are also unaudited. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period. The condensed balance sheet as of December 31, 2023 included herein was derived from the audited financial statements as of that date. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements included in the Company’s prospectus (the Prospectus) dated March 27, 2024 related to its IPO filed pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, with the SEC on March 28, 2024.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions. On an ongoing basis, management evaluates its estimates, primarily related to stock-based compensation, the fair value of its investments and common stock, and accrued research and development costs. These estimates are based on historical data and experience, as well as various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. The Company’s estimates relating to the valuation of stock options require the selection of appropriate valuation methodologies and models, and significant judgment in evaluating ranges of assumptions and financial inputs.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts. The balance reflected in these financial statements as restricted cash represents a deposit account pledged as collateral to secure a standby letter of credit required as a security deposit on one of the Company’s leased facilities. The Company has classified the restricted cash as a noncurrent asset on its balance sheets as of September 30, 2024 and December 31, 2023.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments, which potentially subject the Company to the concentration of credit risk, consist primarily of cash, cash equivalents, and investments. The Company maintains deposits in federally insured financial institutions which exceeded federally insured limits by $3.4 million as of September 30, 2024. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes its exposure to concentration of credit risk.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under U.S. GAAP. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement determined based on assumptions that market participants would use in pricing an asset or liability. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. Cash, cash equivalents, and short-term investments are carried at fair value, determined according to the fair value hierarchy described above. The carrying values of the Company’s prepaid expenses, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis.
Deferred Offering Costs and Common Stock Issuance Costs	Deferred Offering Costs and Common Stock Issuance Costs The Company capitalizes certain legal, professional, accounting, and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. As of September 30, 2024 and December 31, 2023, there were $0 and $2.2 million of deferred offering costs, respectively. At the closing of the IPO, the amounts recorded in deferred offering costs were reclassified to additional paid-in capital within stockholders' equity.
Segments	Segments Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment.
Convertible Preferred Stock	Convertible Preferred Stock The Company’s convertible preferred stock is classified as temporary equity in the accompanying balance sheet as of December 31, 2023 and excluded from stockholders’ equity / (deficit) as the potential redemption of such stock was outside the Company’s control and would have required the redemption of the then-outstanding convertible preferred stock. The convertible preferred stock was not redeemable except for in the event of a liquidation, dissolution, or winding up of the Company. Costs incurred in connection with the issuance of convertible preferred stock were recorded as a reduction of gross proceeds from issuance. The Company did not accrete the carrying values of the convertible preferred stock to the redemption values since the occurrence of these events was not considered probable as of December 31, 2023. Immediately prior to the closing of the IPO on April 2, 2024, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding.
Net Loss Per Share	Net Loss Per Share Basic net loss per common share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock and potentially dilutive securities outstanding during the period. The Company’s potentially dilutive securities, which include its options to purchase common stock, common stock subject to repurchase related to unvested restricted stock and options early exercised, and, for periods through April 2, 2024, convertible preferred stock, have been excluded from the calculation of diluted net loss per share as the effect would reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements As of September 30, 2024, several new accounting pronouncements had been issued by the FASB with future adoption dates. All applicable accounting pronouncements will be adopted by the Company by the date required. Management is reviewing the impact of adoption of all pending accounting pronouncements but is not yet in a position to determine their impact on the Company’s financial statements and the notes thereto.

Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Net loss	$ (48,915)	$ (37,290)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	5,508	2,425
Depreciation and amortization	790	710
Accretion of investments, net	(4,003)	(2,093)
Non-cash lease expense	1,894	1,673
Other		25
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,299)	(2)
Accounts payable and accrued liabilities	2,821	1,114
Operating lease liabilities	(2,074)	(1,731)
Net cash used in operating activities	(45,278)	(35,169)
Cash flows from investing activities
Purchases of investments	(161,029)	(132,703)
Maturities of investments	135,175	78,996
Purchases of property and equipment	(2,070)	(365)
Net cash used in investing activities	(27,924)	(54,072)
Cash flows from financing activities
Proceeds from the issuance of common stock from initial public offering, net of discounts	93,000
Payments of common stock offering costs	(3,349)	(533)
Proceeds from the issuance of convertible preferred stock		100,000
Convertible preferred stock issuance costs		(329)
Proceeds from the exercise of stock options	59	143
Net cash provided by financing activities	89,710	99,281
Net increase in cash and cash equivalents	16,508	10,040
Cash, cash equivalents, and restricted cash at beginning of period	24,266	11,484
Cash, cash equivalents, and restricted cash at end of period	40,774	21,524
Components of cash, cash equivalents, and restricted cash
Cash and cash equivalents	40,214	20,964
Restricted Cash	560	560
Cash, cash equivalents, and restricted cash at end of period	40,774	21,524
Non-cash investing and financing activities
Change in unpaid common stock issuance costs	(197)	1,304
Addition to ROU assets		282
Increase to ROU assets due to remeasurement of lease obligation		645
Vesting of early exercised stock options	5	91
Unpaid property and equipment purchases	$ 106	$ 65

Net Loss Per Common Share - Summary of Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	4,240,549	17,430,850
Conversion of Outstanding Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	0	14,740,840
Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	4,240,477	2,688,005
Options Early Exercised Subject to Future Vesting
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	72	2,005

Stock Options and Stock-Based Compensation - Schedule of Stock Option Activity Under the Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Beginning balance, Number	2,813,937
Granted	4,973,990
Exercise of stock options, shares	(15,211)
Forfeited and expired	(3,532,239)
Ending balance, Number	4,240,477	2,813,937
Vested and expected to vest	4,240,477
Exercisable	1,653,773
Beginning balance, Weighted-Average Exercise Price	$ 4.1
Weighted-Average Exercise Price, Granted	7.71
Weighted-Average Exercise Price, Exercised	3.9
Weighted-Average Exercise Price, Forfeited and expired	6.42
Ending balance, Weighted-Average Exercise Price	6.42	$ 4.1
Weighted-Average Exercise Price, Vested and expected to vest	6.42
Weighted-Average Exercise Price, Exercisable	$ 4.9
Weighted-Average Remaining Term (years)	8 years 4 months 24 days	7 years 9 months 18 days
Weighted-Average Remaining Term (years), Vested and expected to vest	8 years 4 months 24 days
Weighted-Average Remaining Term (years), Exercisable	7 years 4 months 24 days
Aggregate-Intrinsic Value	$ 75	$ 562
Aggregate-Intrinsic Value, Vested and expected to vest	75
Aggregate-Intrinsic Value, Exercisable	$ 75

Investments - Additional Information (Details) $ in Millions	Sep. 30, 2024 Securities	Dec. 31, 2023 USD ($) Securities
Investments, Debt and Equity Securities [Abstract]
Number of available-for-sale securities \| Securities	0	24
Estimated fair value of gross unrealized loss positions \| $		$ 40.3

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	$ 163,370	$ 118,783
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	28,991	21,737
U.S. Government Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	125,980	92,143
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	8,399	4,903
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	28,991	21,737
Level 1 \| Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	28,991	21,737
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	134,379	97,046
Level 2 \| U.S. Government Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	125,980	92,143
Level 2 \| Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	$ 8,399	$ 4,903

Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 40,214	$ 23,706
Short-term investments	126,921	97,046
Prepaid expenses and other current assets	3,314	3,452
Total current assets	170,449	124,204
Property and equipment, net	3,959	2,573
Right-of-use asset, net	109	2,002
Restricted cash	560	560
Other assets	16	555
Total assets	175,093	129,894
Current liabilities
Accounts payable and accrued liabilities	7,041	4,266
Accrued compensation	2,848	2,898
Lease liabilities, current portion	121	2,195
Total current liabilities	10,010	9,359
Commitments and contingencies (Notes 8)
Convertible preferred stock, $0.0001 par value; no shares authorized, issued, or outstanding as of September 30, 2024; 287,446,844 shares authorized, issued, and outstanding as of December 31, 2023; liquidation preference of $252.1 million as of December 31, 2023	0	247,617
Stockholders' equity / (deficit):
Preferred stock, $0.0001 par value; 70,000,000 shares authorized and no shares issued and outstanding as of September 30, 2024; no shares authorized and no shares issued and outstanding as of December 31, 2023	0	0
Common stock, $0.0001 par value; 700,000,000 shares authorized, 22,254,537 shares issued, and 22,254,465 shares outstanding as of September 30, 2024; 402,600,000 shares authorized, 1,248,493 shares issued, and 1,247,012 shares outstanding as of December 31, 2023	2	0
Additional paid-in-capital	349,869	8,987
Accumulated other comprehensive income	236	40
Accumulated deficit	(185,024)	(136,109)
Total stockholders' equity / (deficit)	165,083	(127,082)
Total liabilities, convertible preferred stock, and stockholders' equity / (deficit)	$ 175,093	$ 129,894

Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Common stock reserved for future issuance	6,699,612	18,415,932
Common Stock Options Issued and Outstanding
Class of Stock [Line Items]
Common stock reserved for future issuance	4,240,477	2,813,937
Equity Awards Available for Future Issuance
Class of Stock [Line Items]
Common stock reserved for future issuance	2,227,216	861,155
Shares Available for Purchase Under the ESPP
Class of Stock [Line Items]
Common stock reserved for future issuance	231,919
Conversion of Outstanding Convertible Preferred Stock
Class of Stock [Line Items]
Common stock reserved for future issuance		14,740,840

- 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/exampleRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 272
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483014/272-10-45-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 272
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482987/272-10-50-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(d))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-14

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(27)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(2)(i))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(2)(ii))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

+ Details

Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 0.3	$ 0.2	$ 0.8	$ 0.7

Stock Options and Stock-Based Compensation - Schedule of Stock-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]
Total stock-based compensation	$ 2,045	$ 883	$ 5,508	$ 2,425
Research and Development Expenses
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	801	378	2,214	1,045
General and Administrative Expenses
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 1,244	$ 505	$ 3,294	$ 1,380

Investments

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Investments

The following tables summarize investments accounted for as available-for-sale securities (in thousands):


	As of September 30, 2024
	Acquisition Cost		Unrealized Gain		Unrealized Loss		Estimated Fair Value
Money market funds	$	28,991	$	—	$	—	$	28,991
U.S. government obligations		125,751		229		—		125,980
Corporate debt securities		8,392		7		—		8,399
Total cash equivalents and investments	$	163,134	$	236	$	—	$	163,370
Classified as:
Cash equivalents							$	36,449
Short-term investments								126,921
Total cash equivalents and investments							$	163,370


	As of December 31, 2023
	Acquisition Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
Money market funds	$	21,737	$	—	$	—		$	21,737
U.S. government obligations		92,106		58		(21	)		92,143
Corporate debt securities		4,900		5		(2	)		4,903
Total cash equivalents and investments	$	118,743	$	63	$	(23	)	$	118,783
Classified as:
Cash equivalents								$	21,737
Short-term investments									97,046
Total cash equivalents and investments								$	118,783

On September 30, 2024 and December 31, 2023, the remaining contractual maturities of all the Company’s available-for-sale investments were less than 12 months. As of September 30, 2024 and December 31, 2023, the Company has not established an allowance for credit losses for any of its available-for-sale securities.

As of September 30, 2024, there were no available-for-sale securities in gross unrealized loss positions. As of December 31, 2023, there were 24 available-for-sale securities, with an estimated fair value of $40.3 million in gross unrealized loss positions. Based on its review of these investments as of December 31, 2023, the Company believed that the unrealized losses as of December 31, 2023 reflected the impact of the rising interest rate environment and were not other-than-temporary in nature.

Property and Equipment (Tables)

9 Months Ended

Sep. 30, 2024

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment, Net

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


	September 30,		December 31,
	2024		2023
Lab equipment	$	4,346	$	4,264
Computers and software		853		833
Leasehold improvements		697		46
Furniture and fixtures		1,580		157
Total property and equipment		7,476		5,300
Less accumulated depreciation and amortization		3,517		2,727
Property and equipment, net	$	3,959	$	2,573

Accounts Payable and Accrued Liabilities - Schedule of Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accounts payable	$ 2,542	$ 2,222
Accrued research and development costs	3,427	1,575
Other accrued liabilities	1,072	469
Total accounts payable and accrued liabilities	$ 7,041	$ 4,266

Lease Agreements - Additional Information (Details) $ in Thousands		9 Months Ended
	Dec. 31, 2021 USD ($) ft²	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Nov. 30, 2021
Lessee, Lease, Description [Line Items]
Net ROU asset		$ 109		$ 2,002
2022 Lease
Lessee, Lease, Description [Line Items]
Operating lease term					14 days
Net ROU asset		100
Lease obligation		100
Estimated incremental borrowing rate					8.00%
Future minimum lease payments		100
Cash paid for operating leases		2,100	$ 2,100
2024 Lease
Lessee, Lease, Description [Line Items]
Area of Square Feet \| ft²	80,000
Tenant improvement allowances	$ 22,000
Base lease payments		$ 71,900
Right to extend the term		60 months
Standby letter-of-credit		$ 500
Upfront payments under lease agreements		$ 500

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (16,509)	$ (13,173)	$ (48,915)	$ (37,290)

- Definition

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

+ References

+ Details

Investments (Tables)

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-Sale Securities

The following tables summarize investments accounted for as available-for-sale securities (in thousands):


	As of September 30, 2024
	Acquisition Cost		Unrealized Gain		Unrealized Loss		Estimated Fair Value
Money market funds	$	28,991	$	—	$	—	$	28,991
U.S. government obligations		125,751		229		—		125,980
Corporate debt securities		8,392		7		—		8,399
Total cash equivalents and investments	$	163,134	$	236	$	—	$	163,370
Classified as:
Cash equivalents							$	36,449
Short-term investments								126,921
Total cash equivalents and investments							$	163,370


	As of December 31, 2023
	Acquisition Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
Money market funds	$	21,737	$	—	$	—		$	21,737
U.S. government obligations		92,106		58		(21	)		92,143
Corporate debt securities		4,900		5		(2	)		4,903
Total cash equivalents and investments	$	118,743	$	63	$	(23	)	$	118,783
Classified as:
Cash equivalents								$	21,737
Short-term investments									97,046
Total cash equivalents and investments								$	118,783

Common Stock

9 Months Ended

Sep. 30, 2024

Equity [Abstract]

Common Stock

10.

Common Stock

Common Stock Rights

The holder of each outstanding share of common stock is entitled to one vote on all matters submitted to a vote of the holders of common stock. Subject to the rights of the holders of any class of the Company’s capital stock having any preference or priority over common stock, the holders of common stock are entitled to receive dividends that are declared by the Company’s board of directors out of legally available funds. In the event of a liquidation, dissolution or winding-up, the holders of common stock are entitled to share ratably in the net assets remaining after payment of liabilities and the liquidation value of any class of the Company’s capital stock having any preference or priority over the common stock then outstanding, if any. The common stock has no preemptive rights, conversion rights, redemption rights, preference rights, or exchange rights, or sinking fund provisions, and there are no dividends in arrears or default. All shares of common stock have equal distribution, liquidation and voting rights.

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following:


	As of September 30,		As of December 31,
	2024		2023
Conversion of outstanding convertible preferred stock		—		14,740,840
Common stock options issued and outstanding		4,240,477		2,813,937
Equity awards available for future issuance		2,227,216		861,155
Shares available for purchase under the ESPP		231,919		—
Total		6,699,612		18,415,932

Stock Options and Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Stock Option Activity Under the Plan

Stock option activity under the Plan and certain other related information is as follows:


	Number			Weighted- Average Exercise Price		Weighted- Average Remaining Term (years)		Aggregate- Intrinsic Value (in 000’s)
Balance as of December 31, 2023		2,813,937		$	4.10		7.8	$	562
Granted		4,973,990		$	7.71
Exercised		(15,211	)	$	3.90
Forfeited and expired		(3,532,239	)	$	6.42
Balance as of September 30, 2024		4,240,477		$	6.42		8.4	$	75
Vested and expected to vest at September 30, 2024		4,240,477		$	6.42		8.4	$	75
Exercisable as of September 30, 2024		1,653,773		$	4.90		7.4	$	75

Schedule of Stock-based Compensation Expense

Stock-based compensation expense was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2024		2023		2024		2023
Research and development expenses	$	801	$	378	$	2,214	$	1,045
General and administrative expenses		1,244		505		3,294		1,380
Total stock-based compensation	$	2,045	$	883	$	5,508	$	2,425

Schedule of Excluding Any Effect of the Option Repricing, Weighted-average Assumptions Used in the Black-Scholes Option Pricing Model to Determine the Fair Value of the Stock Options Granted


	Three Months Ended September 30,						Nine Months Ended September 30,
	2024			2023			2024			2023
Expected option life (in years)		6.0			6.1			6.0			6.0
Assumed volatility		90.8	%		95.7	%		90.9	%		92.2	%
Assumed risk-free interest rate		3.8	%		3.9	%		3.9	%		3.9	%
Expected dividend yield		—			—			—			—

Condensed Statements of Convertible Preferred Stock and Stockholders' Equity/(Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional paid-in-capital	Accumulated other comprehensive income/ (loss)	Accumulated deficit
Beginning balance, convertible preferred stock, (in shares) at Dec. 31, 2022		144,589,706
Beginning balance, convertible preferred stock at Dec. 31, 2022		$ 147,946
Beginning balance, (in shares) at Dec. 31, 2022			1,167,240
Beginning balance at Dec. 31, 2022	$ (81,696)			$ 5,377	$ (398)	$ (86,675)
Vesting of early exercised stock options, (in shares)			17,505
Vesting of early exercised stock options, value	52			52
Exercise of stock options Value	31			31
Exercise of stock options (in shares)			9,195
Stock-based compensation	615			615
Unrealized gain (loss) on short-term investments	278				278
Net loss	(11,719)					(11,719)
Ending balance, (in shares) at Mar. 31, 2023			1,193,940
Ending balance at Mar. 31, 2023	(92,439)			6,075	(120)	(98,394)
Ending balance, convertible preferred stock, (in shares) at Mar. 31, 2023		144,589,706
Ending balance, convertible preferred stock at Mar. 31, 2023		$ 147,946
Issuance of Series C convertible preferred stock, net of $329 in issuance costs (in shares)		142,857,138
Issuance of Series C convertible preferred stock, net of $329 in issuance costs		$ 99,671
Vesting of early exercised stock options, (in shares)			12,164
Vesting of early exercised stock options, value	36			36
Exercise of stock options Value	26			26
Exercise of stock options (in shares)			7,209
Stock-based compensation	927			927
Unrealized gain (loss) on short-term investments	(20)				(20)
Net loss	(12,398)					(12,398)
Ending balance, (in shares) at Jun. 30, 2023			1,213,313
Ending balance at Jun. 30, 2023	(103,868)			7,064	(140)	(110,792)
Ending balance, convertible preferred stock, (in shares) at Jun. 30, 2023		287,446,844
Ending balance, convertible preferred stock at Jun. 30, 2023		$ 247,617
Vesting of early exercised stock options, (in shares)			842
Vesting of early exercised stock options, value	3			3
Exercise of stock options Value	86			86
Exercise of stock options (in shares)			20,623
Stock-based compensation	883			883
Unrealized gain (loss) on short-term investments	26				26
Net loss	(13,173)					(13,173)
Ending balance, (in shares) at Sep. 30, 2023			1,234,778
Ending balance at Sep. 30, 2023	$ (116,043)			8,036	(114)	(123,965)
Ending balance, convertible preferred stock, (in shares) at Sep. 30, 2023		287,446,844
Ending balance, convertible preferred stock at Sep. 30, 2023		$ 247,617
Beginning balance, convertible preferred stock, (in shares) at Dec. 31, 2023	287,446,844	287,446,844
Beginning balance, convertible preferred stock at Dec. 31, 2023	$ 247,617	$ 247,617
Beginning balance, (in shares) at Dec. 31, 2023			1,247,012
Beginning balance at Dec. 31, 2023	(127,082)			8,987	40	(136,109)
Vesting of early exercised stock options, (in shares)			522
Vesting of early exercised stock options, value	2			2
Exercise of stock options Value	59			59
Exercise of stock options (in shares)			15,104
Stock-based compensation	1,328			1,328
Unrealized gain (loss) on short-term investments	(61)				(61)
Net loss	(15,430)					(15,430)
Ending balance, (in shares) at Mar. 31, 2024			1,262,638
Ending balance at Mar. 31, 2024	$ (141,184)			10,376	(21)	(151,539)
Ending balance, convertible preferred stock, (in shares) at Mar. 31, 2024		287,446,844
Ending balance, convertible preferred stock at Mar. 31, 2024		$ 247,617
Beginning balance, convertible preferred stock, (in shares) at Dec. 31, 2023	287,446,844	287,446,844
Beginning balance, convertible preferred stock at Dec. 31, 2023	$ 247,617	$ 247,617
Beginning balance, (in shares) at Dec. 31, 2023			1,247,012
Beginning balance at Dec. 31, 2023	$ (127,082)			8,987	40	(136,109)
Exercise of stock options (in shares)	15,211
Ending balance, (in shares) at Sep. 30, 2024			22,254,465
Ending balance at Sep. 30, 2024	$ 165,083		$ 2	349,869	236	(185,024)
Ending balance, convertible preferred stock, (in shares) at Sep. 30, 2024	0
Ending balance, convertible preferred stock at Sep. 30, 2024	$ 0
Beginning balance, convertible preferred stock, (in shares) at Mar. 31, 2024		287,446,844
Beginning balance, convertible preferred stock at Mar. 31, 2024		$ 247,617
Beginning balance, (in shares) at Mar. 31, 2024			1,262,638
Beginning balance at Mar. 31, 2024	(141,184)			10,376	(21)	(151,539)
Conversion of convertible preferred stock into common stock upon initial public offering, (in shares)		(287,446,844)
Conversion of convertible preferred stock into common stock upon initial public offering, value		$ (247,617)
Issuance of common stock in initial public offering, net of $12,305 in discounts and offering costs, (in shares)			6,250,000
Issuance of common stock in initial public offering, net of $12,305 in discounts and offering costs, value	87,695		$ 1	87,694
Conversion of convertible preferred stock into common stock upon initial public offering, (in shares)			14,740,840
Conversion of convertible preferred stock into common stock upon initial public offering, value	247,617		$ 1	247,616
Vesting of early exercised stock options, (in shares)			524
Vesting of early exercised stock options, value	2			2
Exercise of stock options (in shares)			100
Stock-based compensation	2,135			2,135
Unrealized gain (loss) on short-term investments	(43)				(43)
Net loss	(16,976)					(16,976)
Ending balance, (in shares) at Jun. 30, 2024			22,254,102
Ending balance at Jun. 30, 2024	179,246		$ 2	347,823	(64)	(168,515)
Vesting of early exercised stock options, (in shares)			363
Vesting of early exercised stock options, value	1			1
Stock-based compensation	2,045			2,045
Unrealized gain (loss) on short-term investments	300				300
Net loss	(16,509)					(16,509)
Ending balance, (in shares) at Sep. 30, 2024			22,254,465
Ending balance at Sep. 30, 2024	$ 165,083		$ 2	$ 349,869	$ 236	$ (185,024)
Ending balance, convertible preferred stock, (in shares) at Sep. 30, 2024	0
Ending balance, convertible preferred stock at Sep. 30, 2024	$ 0

Organization and Basis of Presentation

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Basis of Presentation

Description of Business

Boundless Bio, Inc. (the Company) is a clinical-stage precision oncology company dedicated to unlocking a new paradigm in cancer therapeutics to address the significant unmet need in patients with oncogene amplified tumors by targeting extrachromosomal DNA (ecDNA). The Company is focused on designing and developing small molecule drugs called ecDNA directed therapeutic candidates (ecDTx). The Company was incorporated in the state of Delaware on April 10, 2018 and is headquartered in San Diego, California.

Initial Public Offering

On April 2, 2024, the Company completed its initial public offering (IPO), pursuant to which it sold 6,250,000 shares of its common stock at a public offering price of $16.00 per share, resulting in net proceeds of approximately $87.7 million, after deducting underwriting discounts, commissions, and other offering expenses. Immediately prior to the closing of the IPO, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding.

In connection with the closing of its IPO, on April 2, 2024, the Company’s certificate of incorporation was amended and restated to authorize 700,000,000 shares of common stock, par value $0.0001 per share, and 70,000,000 shares of undesignated preferred stock, par value of $0.0001 per share.

Reverse Stock Split

On March 19, 2024, the Company effected a one-for-19.5 reverse stock split of its issued and outstanding shares of common stock. Accordingly, all share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustment of the conversion ratios for each series of the Company’s convertible preferred stock. The par value and the number of authorized shares of the convertible preferred stock and common stock were not adjusted in connection with the reverse stock split.

Liquidity

Since the Company commenced operations in 2018, it has devoted substantially all of its efforts and resources to organizing and staffing the Company, business planning, raising capital, building its proprietary Spyglass platform, discovering its ecDTx, developing its ecDNA diagnostic candidate, establishing its intellectual property portfolio, conducting research, preclinical studies, and clinical trials, establishing arrangements with third parties for the manufacture of its ecDTx and related raw materials, and providing other general and administrative support for these operations.

Since inception, the Company has incurred significant operating losses and negative cash flows from its operations and expects that it will continue to do so into the foreseeable future as it continues its development of, seeks regulatory approval for, and potentially commercializes any of its ecDTx and seeks to discover and develop additional ecDTx, utilizes third parties to manufacture its ecDTx and related raw materials, seeks to develop its ecDNA diagnostic candidate, hires additional personnel, and expands and protects its intellectual property. If the Company obtains regulatory approval for any of its ecDTx, it expects to incur significant commercialization expenses related to product sales, marketing, manufacturing, and distribution. As of September 30, 2024, the Company had an accumulated deficit of $185.0 million and cash, cash equivalents, and short-term investments of $167.1 million. The Company believes that its existing cash, cash equivalents, and short-term investments will be sufficient to fund its operations for at least 12 months from the issuance date of these unaudited condensed financial statements.

Basis of Presentation

The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) and the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. The financial statements are presented in U.S. dollars. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB).

Commitments and Contingencies

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Contracts

The Company enters into contracts in the normal course of business with various third parties for preclinical research studies, clinical trials, testing, manufacturing, and other services. These contracts generally provide for termination upon notice and are cancellable without significant penalty or payment and do not contain any minimum purchase commitments.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnification of varying scope 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 agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with officers and members of its 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 officers or directors. The maximum potential future payments the Company could be required to make under these indemnification arrangements is, in many cases, unlimited. To date, the Company has not incurred any material costs because of these indemnifications. The Company has not accrued any liabilities related to

such indemnification arrangements in its financial statements as of September 30, 2024 or December 31, 2023 because it determined the likelihood of incurring a payment obligation pursuant to such arrangements was not probable.

Litigation

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. There are no matters currently outstanding for which any liabilities have been accrued. The Company was not a defendant in any lawsuit for the nine months ended September 30, 2024 or the year ended December 31, 2023.

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Unaudited Condensed Interim Financial Information The condensed balance sheet as of September 30, 2024, the condensed statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023, the condensed statements of convertible preferred stock and stockholders’ equity / (deficit) for the three and nine months ended September 30, 2024 and 2023, and the condensed statements of cash flows for the nine months ended September 30, 2024 and 2023 are unaudited. These unaudited condensed financial statements have been prepared on the same basis as the Company's annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary to present fairly the Company’s financial position, results of operations, and cash flows for the interim period presented. The financial data and the other financial information contained in these notes to the condensed financial statements related to the three and nine months ended September 30, 2024 and 2023 are also unaudited. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period. The condensed balance sheet as of December 31, 2023 included herein was derived from the audited financial statements as of that date. These unaudited condensed financial statements should be read in conjunction with the Company’s audited financial statements included in the Company’s prospectus (the Prospectus) dated March 27, 2024 related to its IPO filed pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, with the SEC on March 28, 2024. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions. On an ongoing basis, management evaluates its estimates, primarily related to stock-based compensation, the fair value of its investments and common stock, and accrued research and development costs. These estimates are based on historical data and experience, as well as various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. The Company’s estimates relating to the valuation of stock options require the selection of appropriate valuation methodologies and models, and significant judgment in evaluating ranges of assumptions and financial inputs. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts. The balance reflected in these financial statements as restricted cash represents a deposit account pledged as collateral to secure a standby letter of credit required as a security deposit on one of the Company’s leased facilities. The Company has classified the restricted cash as a noncurrent asset on its balance sheets as of September 30, 2024 and December 31, 2023. Concentration of Credit Risk Financial instruments, which potentially subject the Company to the concentration of credit risk, consist primarily of cash, cash equivalents, and investments. The Company maintains deposits in federally insured financial institutions which exceeded federally insured limits by $3.4 million as of September 30, 2024. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes its exposure to concentration of credit risk. Fair Value Measurements Certain assets and liabilities are carried at fair value under U.S. GAAP. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement determined based on assumptions that market participants would use in pricing an asset or liability. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. Cash, cash equivalents, and short-term investments are carried at fair value, determined according to the fair value hierarchy described above. The carrying values of the Company’s prepaid expenses, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. Deferred Offering Costs and Common Stock Issuance Costs The Company capitalizes certain legal, professional, accounting, and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. As of September 30, 2024 and December 31, 2023, there were $0 and $2.2 million of deferred offering costs, respectively. At the closing of the IPO, the amounts recorded in deferred offering costs were reclassified to additional paid-in capital within stockholders' equity. Segments Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment. Convertible Preferred Stock The Company’s convertible preferred stock is classified as temporary equity in the accompanying balance sheet as of December 31, 2023 and excluded from stockholders’ equity / (deficit) as the potential redemption of such stock was outside the Company’s control and would have required the redemption of the then-outstanding convertible preferred stock. The convertible preferred stock was not redeemable except for in the event of a liquidation, dissolution, or winding up of the Company. Costs incurred in connection with the issuance of convertible preferred stock were recorded as a reduction of gross proceeds from issuance. The Company did not accrete the carrying values of the convertible preferred stock to the redemption values since the occurrence of these events was not considered probable as of December 31, 2023. Immediately prior to the closing of the IPO on April 2, 2024, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding. Net Loss Per Share Basic net loss per common share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock and potentially dilutive securities outstanding during the period. The Company’s potentially dilutive securities, which include its options to purchase common stock, common stock subject to repurchase related to unvested restricted stock and options early exercised, and, for periods through April 2, 2024, convertible preferred stock, have been excluded from the calculation of diluted net loss per share as the effect would reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same. Recently Adopted Accounting Pronouncements As of September 30, 2024, several new accounting pronouncements had been issued by the FASB with future adoption dates. All applicable accounting pronouncements will be adopted by the Company by the date required. Management is reviewing the impact of adoption of all pending accounting pronouncements but is not yet in a position to determine their impact on the Company’s financial statements and the notes thereto.