0000950170-24-033492 | 10-K | XBRL Viewer

Stockholders Deficit

12 Months Ended

Dec. 31, 2023

8. Stockholders’ Deficit

Shelf Registration Statement

In April 2022, the Company filed a shelf registration statement on Form S-3 ( the “2022 Shelf Registration Statement”), which became effective in May 2022. The 2022 Shelf Registration Statement permits: (i) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $300.0 million of common stock, preferred stock, debt securities and warrants in one or more offerings and in any combination; and (ii) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $100.0 million of our common stock that may be issued and sold under an "at-the-market” sales agreement ( the “ATM Program”). The $100.0 million of common stock that may be issued and sold under the ATM Program is included in the $300.0 million of securities that may be issued and sold under the 2022 Shelf Registration Statement. As of December 31, 2023, the Company has not sold any shares of its common stock under the ATM Program.

Shares Subject to Repurchase

Pursuant to the 2018 Plan, the Company issued shares of restricted common stock to employees, consultants and members of its board of directors. Additionally, certain stock options granted pursuant to the 2018 Plan provide

for the right to elect to exercise unvested options early in exchange for restricted shares of common stock. These restricted shares of common stock generally vest over a four-year period and are subject to repurchase by the Company at the original purchase price or, in certain instances the fair market value if such fair market value is lower than the purchase price, in the event the recipient’s service is terminated either voluntarily or involuntarily prior to vesting.

A summary of the Company’s restricted shares of common stock and unvested stock liability, which is included in accrued expenses and other current liabilities on the Company’s balance sheets, is as follows (in thousands, except share data):


	Shares			Liability
Balance at December 31, 2021		239,826		$	23
Vested shares		(192,108	)		(14	)
Balance at December 31, 2022		47,718			9
Vested shares		(47,718	)		(9	)
Balance at December 31, 2023		—		$	—

- Definition

The entire disclosure for equity.

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+ Details

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2023

Consulting Agreements

Summary of Expenses Recognized under Various Agreements

Expenses recognized by the Company under the 2020 Consulting Agreement during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
General and administrative	$	240	$	240
Total expenses	$	240	$	240

Research Consulting Agreements

Summary of Expenses Recognized under Various Agreements

Expenses recognized by the Company under the Research Consulting Agreement during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	146	$	180
Total expenses	$	146	$	180

Lease Agreement

Summary of Expenses Recognized under Various Agreements

Expenses recognized by the Company under the Lease and Lease Amendment during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	845	$	780
General and administrative		298		290
Total expenses	$	1,143	$	1,070

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 21,200	$ 26,500
Investment securities	260,598	303,887
Prepaid expenses and other current assets	2,786	4,732
Total current assets	284,584	335,119
Property and equipment, net	1,691	1,947
Right-of-use asset, related party	2,938	3,612
Other assets	430	459
Total assets	289,643	341,137
Current liabilities:
Accounts payable	1,940	3,025
Accrued expenses and other current liabilities (including related party amounts of $716 and $640, respectively)	7,682	7,751
Total current liabilities	9,622	10,776
Operating lease liability, net, related party	2,334	3,051
Total liabilities	11,956	13,827
Commitments and contingencies (See Note 11)
Stockholders' equity:
Common stock: $0.0001 par value; 200,000,000 shares authorized, 56,473,598 and 55,943,314 shares issued, and 56,473,598 and 55,895,596 shares outstanding at December 31, 2023 and 2022, respectively	6	6
Additional paid-in capital	455,245	441,424
Accumulated deficit	(177,626)	(110,764)
Accumulated other comprehensive loss	62	(3,356)
Total stockholders' equity	277,687	327,310
Total liabilities and stockholders' equity	$ 289,643	$ 341,137

Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
Statements of Comprehensive Loss - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (66,862)	$ (63,308)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities	3,418	(3,112)
Comprehensive loss	$ (63,444)	$ (66,420)

- Definition

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

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+ Details

Stock-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	12 Months Ended
	Mar. 25, 2021 shares	Aug. 31, 2023 StockOption $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares	Jan. 01, 2024 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Type of stock options granted to purchase common stock \| StockOption		2
Weighted-average grant date fair value per share of options granted \| $ / shares			$ 3.45	$ 8.63
Stock-based compensation expense \| $			$ 13,088	$ 10,925
Aggregate intrinsic value of options exercised \| $			700	4,000
Cash received from options exercised \| $			$ 419	$ 323
Expected dividend yield			0.00%	0.00%
Unrecognized compensation expense \| $			$ 26,800
Weighted-average period in expense expected to be recognized			1 year 6 months
Stock Option One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted to each type of incentive plans to purchase common stock		525,000
Weighted-average grant date fair value per share of options granted \| $ / shares		$ 1.64
Stock-based compensation expense \| $			$ 100
Stock Option Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options granted to each type of incentive plans to purchase common stock		525,000
Weighted-average grant date fair value per share of options granted \| $ / shares		$ 1.64
2021 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock remained available for issuance			5,102,732
Common stock issuance, description and terms			the number of shares of common stock available for issuance under the 2021 Plan will automatically increase on January 1 of each calendar year through January 1, 2031 in an amount equal to 5% of the total number of shares outstanding of the Company’s common stock on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Company’s board of directors.
2021 Equity Incentive Award Plan \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance					7,926,411
Number of shares available for future issuance increased					2,823,679
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance			1,583,474
Common stock remained available for issuance	1,200,000
Common stock issuance, description and terms			the number of shares of common stock available for issuance under the ESPP will automatically increase on January 1 of each calendar year through January 1, 2031 in an amount equal to the lesser of (i) 1% of the total number of shares outstanding of the Company’s common stock on the last day of the calendar month before the date of each automatic increase and (ii) 1,200,000 shares; provided that before the date of any such increase, the Company’s board of directors may determine that such increase will be less than the amount set forth in clauses (i) and (ii).
Expected dividend yield			0.00%	0.00%
Maximum percentage of eligible earnings withheld to participate in offering	15.00%
Price of common stock purchased	85.00%
Issuance of common stock under employee stock purchase plan, Shares			132,776
Unrecognized compensation expense \| $			$ 500
Weighted-average period in expense expected to be recognized			1 year 9 months 18 days
2021 Employee Stock Purchase Plan \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance					2,148,209
Number of shares available for future issuance increased					564,735

Stock-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

9. Stock-Based Compensation

Equity Incentive Award Plans

In March 2021, the Company’s board of directors and stockholders adopted the 2021 Plan, which became effective on March 25, 2021, the date of the underwriting agreement related to the Company’s initial public offering (“IPO”). Upon adoption of the 2021 Plan, the Company restricted future grants from its 2018 Plan.

Under the 2021 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, performance stock awards, performance cash awards and other forms of stock awards to employees, directors and consultants, including employees and consultants of the Company’s affiliates. As of December 31, 2023, the Company had 5,102,732 shares available for grant under the 2021 Plan. In addition, the number of shares of common stock available for issuance under the 2021 Plan will automatically increase on January 1 of each calendar year through January 1, 2031 in an amount equal to 5% of the total number of shares outstanding of the Company’s common stock on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Company’s board of directors. Effective January 1, 2024, the number of shares available for future issuance was increased by 2,823,679 shares so that the total available for future issuance as of January 1, 2024 was 7,926,411 shares.

In August 2023, the Company granted two stock options, each to purchase up to 525,000 shares of the Company's common stock, which contain both time-based and performance-based conditions. The options have a weighted average grant date fair value of $1.64 per share. Stock-based compensation expense for awards with performance conditions is recognized ratably over the expected performance period when the achievement of such performance conditions is determined to be probable. During the year-ended December 31, 2023, the Company

assessed the probability of achieving the performance-based conditions and recorded approximately $0.1 million in general and administrative stock-based compensation expense.

A summary of the Company's stock option activity for the periods presented was as follows (in thousands, except year, share and per share data):


						Weighted-
						Average
	Number of			Weighted-		Remaining
	Options and			Average		Contractual		Aggregate
	Awards			Exercise		Term		Intrinsic
	Outstanding			Price		(Years)		Value
Outstanding at December 31, 2021		2,673,775		$	8.49		9.12	$	35,343
Granted		3,132,283		$	13.50
Exercised		(226,128	)	$	1.43
Canceled/Expired		(183,211	)	$	9.81
Outstanding at December 31, 2022		5,396,719		$	11.64		8.75	$	10,533,451
Granted		5,299,250		$	5.26
Exercised		(444,398	)	$	0.94
Canceled/Expired		(1,689,818	)	$	9.51
Outstanding at December 31, 2023		8,561,753		$	8.67		8.46	$	1,115,560
Vested and expected to vest at December 31, 2023		7,911,753		$	9.18		8.36	$	1,008,810
Exercisable at December 31, 2023		2,296,750		$	12.47		6.95	$	538,297

The weighted-average grant date fair value per share of options granted was $3.45 and $8.63 for the years ended December 31, 2023 and 2022, respectively. The aggregate intrinsic value of options exercised was $0.7 million and $4.0 million for the years ended December 31, 2023 and 2022, respectively, and the cash received from options exercised was $0.4 million and $0.3 million for the years ended December 31, 2023 and 2022, respectively.

The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants for the periods presented were as follows:


	Year Ended December 31,
	2023			2022
Expected term (years)		6.10			6.10
Expected volatility		70.0	%		70.4	%
Risk-free interest rate		3.87	%		2.01	%
Expected dividend yield		0.0	%		0.0	%

The Company determines the assumptions used in the option pricing model in the following manner:

Expected Term—The expected term of stock options represents the period of time that the awards are expected to be outstanding. Because the Company does not have sufficient historical exercise behavior, it determines the expected term assumption using the simplified method for employees and board members, which calculates the expected term as the average time-to-vesting and the contractual life of the award. The expected term for non-employees is generally the contractual term.

Expected Volatility—Given the Company's limited historical stock price volatility data, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available.

Risk-Free Interest Rate—The risk-free rate assumption is based on the U.S. Treasury yield in effect at the time of the grant with maturities consistent with the expected term of the awards.

Expected Dividend Yield—The expected dividend yield assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends and, therefore, used an expected dividend yield of zero.

2021 Employee Stock Purchase Plan

In March 2021, the Company’s board of directors and stockholders adopted the ESPP, which became effective on March 25, 2021, the date of the underwriting agreement related to the Company’s IPO. The ESPP permits eligible employees who elect to participate in an offering under the ESPP to have up to 15% of their eligible earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the ESPP. The price of common stock purchased under the ESPP is equal to 85% of the lower of the fair market value of the common stock at the commencement date of each offering period or the relevant date of purchase.

As of December 31, 2023, the Company had issued 132,776 shares of the Company's common stock under the ESPP and had 1,583,474 shares available for future issuance. In addition, the number of shares of common stock available for issuance under the ESPP will automatically increase on January 1 of each calendar year through January 1, 2031 in an amount equal to the lesser of (i) 1% of the total number of shares outstanding of the Company’s common stock on the last day of the calendar month before the date of each automatic increase and (ii) 1,200,000 shares; provided that before the date of any such increase, the Company’s board of directors may determine that such increase will be less than the amount set forth in clauses (i) and (ii). Effective January 1, 2024, the number of shares available for issuance was increased by 564,735 shares so that the total available for future issuance as of January 1, 2024 was 2,148,209 shares.

In determining the grant date fair value of shares to be issued under the ESPP, the Company uses the Black-Scholes option pricing model. The Black-Scholes inputs are determined in the same manner as for stock option awards. The weighted average inputs used for the ESPP for the year ended December 31, 2023, were as follows:


	Year Ended December 31,
	2023			2022
Expected term (years)		1.51			1.26
Expected volatility		85.4	%		78.0	%
Risk-free interest rate		4.44	%		2.78	%
Expected dividend yield		0.0	%		0.0	%

Stock-based compensation expense for all equity awards has been reported in the statements of operations and comprehensive loss as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	6,152	$	4,827
General and administrative		6,936		6,098
Total	$	13,088	$	10,925

As of December 31, 2023, unrecognized compensation expense related to unvested stock option awards was $26.8 million, which is expected to be recognized in expense over a weighted-average period of 1.5 years. As of December 31, 2023, unrecognized compensation expense related to ESPP rights was $0.5 million, which is expected to be recognized over a remaining period of 1.8 years.

Organization

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Organization

1. Organization

Design Therapeutics, Inc. (the “Company”) was incorporated in Delaware in December 2017 and is based in Carlsbad, California. The Company is a biopharmaceutical company pioneering the research and development of GeneTACTM molecules, which are a novel class of small-molecule gene targeted chimera therapeutic candidates designed to be disease-modifying by addressing the underlying cause of diseases caused by inherited nucleotide repeat expansion mutations. The Company’s lead product candidate is in Friedreich ataxia (“FA”), its second product candidate is in Fuchs endothelial corneal dystrophy (“FECD”), and it is also advancing its GeneTACTM program to address other serious nucleotide repeat-driven monogenic diseases.

Liquidity and Capital Resources

The accompanying financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has incurred net operating losses since inception and had an accumulated deficit of $177.6 million as of December 31, 2023. The Company had cash, cash equivalents and investment securities of $281.8 million as of December 31, 2023, and has not generated positive cash flow from operations.

Management expects to incur net losses for the foreseeable future. There can be no assurance that the Company will ever earn revenues or achieve profitability, or if achieved, that they will be sustained on a continuing basis. In addition, the research, product development, and clinical development activities as well as the commercialization of the Company’s products, if approved, will require significant additional financing. The Company may be unable to secure such financing when needed, or if available, such financings may be under terms that are unfavorable to the Company or the current stockholders. If the Company is unable to raise additional funds when needed, it may be required to delay, reduce the scope of, or eliminate development programs, which may adversely affect its business and operations. The Company’s currently available cash and cash equivalents as of December 31, 2023 are sufficient to meet its anticipated cash requirements for more than 12 months following the date the financial statements are issued.

Stock-Based Compensation - Stock-Based Compensation Expense for Equity Awards Reported in Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 13,088	$ 10,925
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	6,152	4,827
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,936	$ 6,098

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Section 50
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-Subparagraph (c)(1)(ii)
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
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-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Section 50
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-Subparagraph (c)(2)(i)
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 21: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2003/role/disclosureRef
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Reference 27: http://www.xbrl.org/2003/role/disclosureRef
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Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Income Taxes - Summary of Changes to Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 929	$ 418
Increase related to prior year tax positions	87
Increase to current year tax positions	783	511
Balance at end of period	$ 1,799	$ 929

Fair Value Measurements - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 280,217	$ 324,782
Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	19,619	20,895
Certificates of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	14,336	7,929
U.S. Treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	221,304	265,966
U.S. Government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	24,958	29,992
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	255,259	294,790
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Money market funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	19,619	20,895
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Certificates of deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	14,336	7,929
Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Treasury securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	221,304	265,966
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	24,958	29,992
Significant Other Observable Inputs (Level 2) \| U.S. Government agency securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investments, fair value disclosure	$ 24,958	$ 29,992

Balance Sheet Details (Tables)

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Prepaid expenses	$	1,354	$	3,617
Interest receivable		1,432		1,115
Total	$	2,786	$	4,732

Summary of Property and Equipment

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


	December 31, 2023			December 31, 2022
Laboratory equipment	$	1,976		$	1,695
Computer equipment and software		102			102
Furniture and fixtures		521			521
Leasehold improvements		151			151
Construction in progress		—			—
		2,750			2,469
Less accumulated depreciation		(1,059	)		(522	)
Total	$	1,691		$	1,947

Summary of Accrued Expenses and Other Current Liabilities

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


	December 31, 2023		December 31, 2022
Accrued personnel costs	$	4,034	$	3,543
Accrued research and development costs		2,350		2,983
Current portion of operating lease liability, related party		716		640
Accrued other		582		585
Total	$	7,682	$	7,751

Leases - Additional Information (Details) $ in Millions	1 Months Ended	12 Months Ended
Leases - Additional Information (Details) $ in Millions	Feb. 28, 2021 ft²	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($)
Lessee, Lease, Description [Line Items]
Rent expense \| $		$ 0.9	$ 0.9
Crossing Holdings, LLC
Lessee, Lease, Description [Line Items]
Area of lease space \| ft²	12,370	4,900
Lease commencement date	2021-09
Lease term	72 months
Option to renew lease term ends, year	2027	2027
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Lease term, option to extend period	three years
Percentage of annual increase in lease payments	3.00%
Weighted average operating lease remaining lease term		3 years 8 months 12 days
Weighted average operating lease right-of-use asset discount rate		7.37%

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded in Calculation of Diluted Net Loss Per Share

The following table sets forth the outstanding, potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive:


	December 31, 2023		December 31, 2022
Stock options		8,561,753		5,396,719
Shares subject to repurchase		—		47,718
Employee stock purchase plan		19,907		7,096
Total		8,581,660		5,451,533

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation and Use of Estimates

The financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and anticipated actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and investment securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institution in which those deposits are held. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities at the date of acquisition of three months or less to be cash equivalents. These investments may include money market accounts, money market funds, U.S. Government agency securities, corporate debt securities and commercial paper. The carrying amounts approximate fair value due to the short maturities of these instruments. The Company’s cash reserves are in a readily available checking account.

Investment Securities

Investments in securities with maturities at the date of acquisition of more than three months are considered marketable securities. These investments may include money market accounts, money market funds, certificates of deposits, U.S. Treasury securities and high quality, marketable debt instruments of corporations and government sponsored enterprises. The Company determines the appropriate classification of its investments at the time of acquisition and reevaluates such determination at each balance sheet date. The Company has classified its investment holdings as available-for-sale, as the sale of such securities may be required prior to maturity to implement management strategies. Further, the Company classifies its available-for-sale investment securities, including those with maturities beyond one year, as current assets on its balance sheets based on the highly liquid nature of the securities and because these investments are considered available for use in current operations. The Company’s investment policy sets minimum credit quality criteria and maximum maturity limits on its investments to provide for safety of principle, liquidity and a reasonable rate of return. Available-for-sale securities are recorded at fair value, based on current market valuations. Unrealized holding gains and losses on available-for-sale securities are excluded from earnings and are reported as a separate component of other comprehensive income (loss) until realized. Allowances for credit losses are reported on the balance sheet, if any.

The cost of available-for-sale investment securities is adjusted for amortization of premiums and accretion of discounts until the securities mature. Such amortization and accretion is included in other income, net on the statements of operations. Realized gains and losses, if any, are also included in other income, net on the statement of operations and are derived using the specific identification method for determining the cost of the securities sold. During the periods presented, no realized gains or losses were recorded on the sale of investment securities and no impairments to reduce the value of any security was taken. See Note 5 for further discussion.

Property and Equipment, Net

Property and equipment generally consist of laboratory equipment, computer equipment and software, and furniture and fixtures and are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three years to five years). Leasehold improvements are recorded at cost and are depreciated on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful lives of the assets. Repairs and maintenance costs are charged as incurred.

An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. The Company has not recognized any impairment losses for the years ended December 31, 2023 and 2022.

Leases

Leases consist of an operating lease the Company has related to its facility. At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term. The expected lease term includes noncancelable lease periods and, when applicable, periods covered by an option to extend the lease if the Company is reasonably certain to exercise that option, as well as periods covered by an option to terminate the lease if the Company is reasonably certain not to exercise the option. For those leases where the implicit rate is not provided, the Company calculates the present value of lease payments using an incremental borrowing rate. The Company's incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use (“ROU”) lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (“Short-Term

Leases”). For any Short-Term leases, the Company records the rent expense on a straight-line basis and ROU asset and lease obligations are not recognized.

After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement and (ii) the ROU asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term.

Research and Development Expenses

Research and development expenses are charged to expense in the period in which they are incurred and are comprised of the following types of costs incurred in connection with research and development activities and clinical trials: lab supplies and outside services incurred in connection with the Company’s early discovery efforts, contract services for clinical trials and related clinical manufacturing costs, salaries and benefits including share-based compensation expense, costs for allocated facilities and depreciation of equipment.

Patent Costs

Costs related to filing and pursuing patent applications are recorded as general and administrative expenses in the statements of operations and expensed as incurred since recoverability of such expenditures is uncertain.

Stock-Based Compensation

Stock options and restricted stock issued pursuant to the Company’s 2021 Equity Incentive Plan (the “2021 Plan”) and 2018 Equity Incentive Plan (the “2018 Plan”), and option features associated with the rights to purchase shares pursuant to the Company’s 2021 Employee Stock Purchase Plan (the “ESPP”) are valued using the Black-Scholes option pricing model on the date of grant or subscription period. This option pricing model involves a number of estimates, including the expected lives of the stock options or subscription period, the Company's anticipated stock volatility and interest rates. The Company recognizes the expense for equity awards on a ratable basis over the requisite service periods of the awards or the number of shares estimated to be issued pursuant to the ESPP. Forfeitures are recognized as they occur.

Income Taxes

The Company uses the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.

The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.

Recent Accounting Pronouncements

In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2023-07, Accounting Standards Codification (ASC) Topic 280, Segment Reporting: Improvements to Reportable Segment Disclosures, which expands annual and interim disclosure requirements for reportable segments, primarily through enhanced disclosures about significant segment expenses. The ASU also requires public entities with a single reportable segment to provide all segment disclosures under ASC 280, including the new disclosures under the ASU. Annual disclosures are required for fiscal years beginning after December 15, 2023 and for interim disclosures within fiscal years beginning after December 15, 2024. Retrospective application is required

and early adoption is permitted. The Company is currently evaluating the impact that the updated standard will have on its financial statement disclosures.

In December 2023, the FASB issued ASU 2023-09, ASC Topic 740, Income Taxes: Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact that the updated standard will have on its financial statement disclosures.

Balance Sheet Details - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses	$ 1,354	$ 3,617
Interest receivable	1,432	1,115
Total	$ 2,786	$ 4,732

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Expected tax benefit at federal statutory rate	$ (14,042)	$ (13,295)
State income taxes, net of federal benefit	(37)	(15)
Research and development credits	(3,722)	(2,075)
Stock-based compensation	906	697
Other	515	(200)
Change in valuation allowance	$ 16,380	$ 14,888

Stockholders Deficit - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2022	Dec. 31, 2023
Maximum
Stockholders Deficit [Line Items]
Aggregate offering price	$ 300.0
Common Stock \| 2018 Equity Incentive Plan \| Restricted Shares
Stockholders Deficit [Line Items]
Vesting period		4 years
ATM Program
Stockholders Deficit [Line Items]
Number of shares sold		0
ATM Program \| Maximum
Stockholders Deficit [Line Items]
Aggregate offering price	$ 100.0

Income Taxes - Schedule of Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating losses	$ 15,074	$ 12,240
Capitalized research costs	16,635	8,396
Research and development credits	6,996	3,274
Lease liability	641	776
Stock-based compensation	3,255	1,740
Other	810	1,519
Total gross deferred tax assets	43,411	27,945
Valuation allowance	(42,436)	(26,777)
Total deferred tax assets	975	1,168
Deferred tax liabilities:
Right of use asset	(618)	(759)
Other	(357)	(409)
Total deferred tax liabilities	$ (975)	$ (1,168)

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and anticipated actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions.
Concentration of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and investment securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institution in which those deposits are held. Additionally, the Company has established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities at the date of acquisition of three months or less to be cash equivalents. These investments may include money market accounts, money market funds, U.S. Government agency securities, corporate debt securities and commercial paper. The carrying amounts approximate fair value due to the short maturities of these instruments. The Company’s cash reserves are in a readily available checking account.
Investment Securities	Investment Securities Investments in securities with maturities at the date of acquisition of more than three months are considered marketable securities. These investments may include money market accounts, money market funds, certificates of deposits, U.S. Treasury securities and high quality, marketable debt instruments of corporations and government sponsored enterprises. The Company determines the appropriate classification of its investments at the time of acquisition and reevaluates such determination at each balance sheet date. The Company has classified its investment holdings as available-for-sale, as the sale of such securities may be required prior to maturity to implement management strategies. Further, the Company classifies its available-for-sale investment securities, including those with maturities beyond one year, as current assets on its balance sheets based on the highly liquid nature of the securities and because these investments are considered available for use in current operations. The Company’s investment policy sets minimum credit quality criteria and maximum maturity limits on its investments to provide for safety of principle, liquidity and a reasonable rate of return. Available-for-sale securities are recorded at fair value, based on current market valuations. Unrealized holding gains and losses on available-for-sale securities are excluded from earnings and are reported as a separate component of other comprehensive income (loss) until realized. Allowances for credit losses are reported on the balance sheet, if any. The cost of available-for-sale investment securities is adjusted for amortization of premiums and accretion of discounts until the securities mature. Such amortization and accretion is included in other income, net on the statements of operations. Realized gains and losses, if any, are also included in other income, net on the statement of operations and are derived using the specific identification method for determining the cost of the securities sold. During the periods presented, no realized gains or losses were recorded on the sale of investment securities and no impairments to reduce the value of any security was taken. See Note 5 for further discussion.
Property and Equipment, Net	Property and Equipment, Net Property and equipment generally consist of laboratory equipment, computer equipment and software, and furniture and fixtures and are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three years to five years). Leasehold improvements are recorded at cost and are depreciated on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful lives of the assets. Repairs and maintenance costs are charged as incurred. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. The Company has not recognized any impairment losses for the years ended December 31, 2023 and 2022.
Leases	Leases Leases consist of an operating lease the Company has related to its facility. At lease commencement, the Company records a lease liability based on the present value of lease payments over the expected lease term. The expected lease term includes noncancelable lease periods and, when applicable, periods covered by an option to extend the lease if the Company is reasonably certain to exercise that option, as well as periods covered by an option to terminate the lease if the Company is reasonably certain not to exercise the option. For those leases where the implicit rate is not provided, the Company calculates the present value of lease payments using an incremental borrowing rate. The Company's incremental borrowing rate for a lease is the rate of interest it would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. At the lease commencement date, the Company records a corresponding right-of-use (“ROU”) lease asset based on the lease liability, adjusted for any lease incentives received and any initial direct costs paid to the lessor prior to the lease commencement date. The Company may enter into leases with an initial term of 12 months or less (“Short-Term Leases”). For any Short-Term leases, the Company records the rent expense on a straight-line basis and ROU asset and lease obligations are not recognized. After lease commencement, the Company measures its leases as follows: (i) the lease liability based on the present value of the remaining lease payments using the discount rate determined at lease commencement and (ii) the ROU asset based on the remeasured lease liability, adjusted for any unamortized lease incentives received, any unamortized initial direct costs and the cumulative difference between rent expense and amounts paid under the lease agreement. Any lease incentives received and any initial direct costs are amortized on a straight-line basis over the expected lease term. Rent expense is recorded on a straight-line basis over the expected lease term.
Research and Development Expenses	Research and Development Expenses Research and development expenses are charged to expense in the period in which they are incurred and are comprised of the following types of costs incurred in connection with research and development activities and clinical trials: lab supplies and outside services incurred in connection with the Company’s early discovery efforts, contract services for clinical trials and related clinical manufacturing costs, salaries and benefits including share-based compensation expense, costs for allocated facilities and depreciation of equipment.
Patent Costs	Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expenses in the statements of operations and expensed as incurred since recoverability of such expenditures is uncertain.
Stock-Based Compensation	Stock-Based Compensation Stock options and restricted stock issued pursuant to the Company’s 2021 Equity Incentive Plan (the “2021 Plan”) and 2018 Equity Incentive Plan (the “2018 Plan”), and option features associated with the rights to purchase shares pursuant to the Company’s 2021 Employee Stock Purchase Plan (the “ESPP”) are valued using the Black-Scholes option pricing model on the date of grant or subscription period. This option pricing model involves a number of estimates, including the expected lives of the stock options or subscription period, the Company's anticipated stock volatility and interest rates. The Company recognizes the expense for equity awards on a ratable basis over the requisite service periods of the awards or the number of shares estimated to be issued pursuant to the ESPP. Forfeitures are recognized as they occur.
Income Taxes	Income Taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made. The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) No. 2023-07, Accounting Standards Codification (ASC) Topic 280, Segment Reporting: Improvements to Reportable Segment Disclosures, which expands annual and interim disclosure requirements for reportable segments, primarily through enhanced disclosures about significant segment expenses. The ASU also requires public entities with a single reportable segment to provide all segment disclosures under ASC 280, including the new disclosures under the ASU. Annual disclosures are required for fiscal years beginning after December 15, 2023 and for interim disclosures within fiscal years beginning after December 15, 2024. Retrospective application is required and early adoption is permitted. The Company is currently evaluating the impact that the updated standard will have on its financial statement disclosures. In December 2023, the FASB issued ASU 2023-09, ASC Topic 740, Income Taxes: Improvements to Income Tax Disclosures, which requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact that the updated standard will have on its financial statement disclosures.

Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning Balance at Dec. 31, 2021	$ 382,130	$ 6	$ 429,824	$ (244)	$ (47,456)
Beginning Balance, Shares at Dec. 31, 2021		55,441,926
Exercises of stock options and vesting of restricted stock	336		336
Exercises of stock options and vesting of restricted stock, Shares		418,236
Issuance of common stock under employee stock purchase plan	339		339
Issuance of common stock under employee stock purchase plan, Shares		35,434
Stock-based compensation	10,925		10,925
Unrealized gain (loss) on investments	(3,112)			(3,112)
Net loss	(63,308)				(63,308)
Ending Balance at Dec. 31, 2022	327,310	$ 6	441,424	(3,356)	(110,764)
Ending Balance, Shares at Dec. 31, 2022		55,895,596
Exercises of stock options and vesting of restricted stock	428		428
Exercises of stock options and vesting of restricted stock, Shares		492,116
Issuance of common stock under employee stock purchase plan	305		305
Issuance of common stock under employee stock purchase plan, Shares		85,886
Stock-based compensation	13,088		13,088
Unrealized gain (loss) on investments	3,418			3,418
Net loss	(66,862)				(66,862)
Ending Balance at Dec. 31, 2023	$ 277,687	$ 6	$ 455,245	$ 62	$ (177,626)
Ending Balance, Shares at Dec. 31, 2023		56,473,598

- Definition

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

+ References

+ Details

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

+ References

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+ Details

License Agreement - Additional Information (Details) - License Agreement - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Schedule Of License Agreement [Line Items]
Milestone payment		$ 100,000
Written notice period for termination of agreement	90 days
Termination period Description	WARF may terminate the License Agreement with 90 days written notice if first commercial sale does not occur before December 31, 2031. Unless terminated earlier by the parties, the term of the License Agreement will continue until the last licensed patent expires in all countries.
Investigation New Drug (IND) \| Maximum
Schedule Of License Agreement [Line Items]
Expected milestone payment on achieving certain regulatory and commercial milestones		17,500,000
Investigation New Drug (IND) \| Minimum
Schedule Of License Agreement [Line Items]
Expected royalty payments upon first commercial product sale		$ 100,000
Research and Development
Schedule Of License Agreement [Line Items]
Upfront payment upon execution of agreement	$ 300,000

Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Contributions made under plan	$ 0.5	$ 0.3

Related Party Transactions - Additional Information (Details)	1 Months Ended				12 Months Ended
	Nov. 30, 2023 $ / shares shares	Mar. 31, 2020 USD ($)	Jan. 31, 2019 ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($) $ / shares
Related Party Transaction [Line Items]
Accrued expenses and other current liabilities, related party amounts					$ 716,000	$ 640,000
Grant date fair value \| $ / shares					$ 3.45	$ 8.63
Stock-based compensation expense					$ 13,088,000	$ 10,925,000
Consulting Agreements
Related Party Transaction [Line Items]
Accrued expenses and other current liabilities, related party amounts					0	$ 15,000
Marlinspike Group, LLC \| 2020 Consulting Agreement
Related Party Transaction [Line Items]
Monthly fee for consultancy services		$ 20,000
Termination fee		$ 240,000
Marlinspike Group, LLC \| Carlsbad, California \| 2019 Consulting Agreement
Related Party Transaction [Line Items]
Area of office space \| ft²			2,120
Aseem Z. Ansari, Ph.D. \| Consulting Agreements
Related Party Transaction [Line Items]
Monthly fee for services				$ 15,000
Option to purchase \| shares	100,000
Grant date fair value \| $ / shares	$ 1.72
Stock-based compensation expense					$ 11,000

Net Loss Per Share

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Net Loss Per Share

3. Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of stock options outstanding under the Company’s equity incentive plans, restricted common stock subject to repurchase, and employee stock purchase rights under the Company’s ESPP, as applicable. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company's net loss position.


	December 31, 2023		December 31, 2022
Stock options		8,561,753		5,396,719
Shares subject to repurchase		—		47,718
Employee stock purchase plan		19,907		7,096
Total		8,581,660		5,451,533

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Impairment losses	$ 0	$ 0
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	5 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives	3 years

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Significant Components of Net Deferred Tax Assets

Significant components of the Company's net deferred tax assets at December 31, 2023 and 2022 were as follows (in thousands):


	December 31, 2023			December 31, 2022
Deferred tax assets:
Net operating losses	$	15,074		$	12,240
Capitalized research costs		16,635			8,396
Research and development credits		6,996			3,274
Lease liability		641			776
Stock-based compensation		3,255			1,740
Other		810			1,519
Total gross deferred tax assets		43,411			27,945
Valuation allowance		(42,436	)		(26,777	)
Total deferred tax assets		975			1,168
Deferred tax liabilities:
Right of use asset		(618	)		(759	)
Other		(357	)		(409	)
Total deferred tax liabilities		(975	)		(1,168	)
Net deferred tax assets	$	—		$	—

Schedule of Reconciliation of Income Tax Expense (Benefit)

A reconciliation of the Company's income tax expense (benefit) to the amount computed by applying the federal statutory income tax rate for the periods presented were as follows (in thousands):


	December 31, 2023			December 31, 2022
Expected tax benefit at federal statutory rate	$	(14,042	)	$	(13,295	)
State income taxes, net of federal benefit		(37	)		(15	)
Research and development credits		(3,722	)		(2,075	)
Stock-based compensation		906			697
Other		515			(200	)
Change in valuation allowance		16,380			14,888
Provision for income taxes	$	—		$	—

Summary of Changes to Unrecognized Tax Benefits

The following table summarizes the changes to the Company's unrecognized tax benefits for the periods presented (in thousands):


	December 31, 2023		December 31, 2022
Balance at beginning of period	$	929	$	418
Increase related to prior year tax positions		87		—
Increase to current year tax positions		783		511
Balance at end of period	$	1,799	$	929

Stockholders Deficit - Summary of Restricted Shares of Common Stock and Unvested Stock Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Liabilities And Stockholders Equity [Line Items]
Beginning Balance, Unvested stock liability	$ 9	$ 23
Vested shares, Unvested stock liability	$ (9)	$ (14)
Restricted Shares
Liabilities And Stockholders Equity [Line Items]
Beginning Balance	47,718	239,826
Vested shares	(47,718)	(192,108)
Ending Balance		47,718

Organization - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Accumulated deficit	$ (177,626)	$ (110,764)
Cash, cash equivalents and investment securities	$ 281,800

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

License Agreement

12 Months Ended

Dec. 31, 2023

License Agreement [Abstract]

License Agreement

12. License Agreement

In February 2019, the Company entered into a Human Therapeutics Exclusive License Agreement (the “License Agreement”) with the Wisconsin Alumni Research Foundation (“WARF”). Under the License Agreement, the Company licensed the exclusive, worldwide, royalty-bearing, sublicensable rights to certain WARF patents and the nonexclusive worldwide rights to certain know-how to develop and commercialize products for the prevention, diagnosis and treatment of disease. As consideration for the license, the Company agreed to pay an upfront fee of $0.3 million, which the Company immediately expensed as research and development expense in its statements of operations as there was no alternative future use for the license.

In 2022, pursuant to the License Agreement, the Company paid $0.1 million upon the acceptance of an Investigational New Drug Application (“IND”) in the U.S. The Company will be required to make further aggregate milestone payments of up to $17.5 million upon achievement of certain other regulatory and commercial milestones. The Company may also be required to pay royalties based on annual net product sales in the low single digits on its or its sublicensees’ net product sales on a country-by-country and product-by-product basis, and is subject to a minimum royalty of $0.1 million per calendar year upon first commercial product sale. Further, the Company may be required to pay sublicense fees in the mid-single digits percentage for fees, royalties or other payments earned from the granting of sublicenses to the WARF patents and know-how.

The Company is responsible for reimbursing WARF for costs incurred in connection with prosecuting and maintaining patent rights that are specific to the License Agreement. Expenses recognized in connection with legal patent fees under this License Agreement were immaterial for the years ended December 31, 2023 and 2022.

The Company may terminate the License Agreement with 90 days written notice or for certain breaches of the agreement. WARF may terminate the License Agreement with 90 days written notice if first commercial sale does not occur before December 31, 2031. Unless terminated earlier by the parties, the term of the License Agreement will continue until the last licensed patent expires in all countries.

Statements of Operations (Parenthetical) - Related Party - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Research and development expenses related party amount	$ 991	$ 960
General and administrative expenses related party amount	$ 538	$ 530

Balance Sheet Details - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Accrued personnel costs	$ 4,034	$ 3,543
Accrued research and development costs	2,350	2,983
Current portion of operating lease liability, related party	$ 716	$ 640
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Other Accrued Liabilities, Current	Accounts Payable and Other Accrued Liabilities, Current
Accrued other	$ 582	$ 585
Total	$ 7,682	$ 7,751

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Summary of Stock Option Activity

A summary of the Company's stock option activity for the periods presented was as follows (in thousands, except year, share and per share data):


						Weighted-
						Average
	Number of			Weighted-		Remaining
	Options and			Average		Contractual		Aggregate
	Awards			Exercise		Term		Intrinsic
	Outstanding			Price		(Years)		Value
Outstanding at December 31, 2021		2,673,775		$	8.49		9.12	$	35,343
Granted		3,132,283		$	13.50
Exercised		(226,128	)	$	1.43
Canceled/Expired		(183,211	)	$	9.81
Outstanding at December 31, 2022		5,396,719		$	11.64		8.75	$	10,533,451
Granted		5,299,250		$	5.26
Exercised		(444,398	)	$	0.94
Canceled/Expired		(1,689,818	)	$	9.51
Outstanding at December 31, 2023		8,561,753		$	8.67		8.46	$	1,115,560
Vested and expected to vest at December 31, 2023		7,911,753		$	9.18		8.36	$	1,008,810
Exercisable at December 31, 2023		2,296,750		$	12.47		6.95	$	538,297

Weighted-Average Assumptions Used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants

The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants for the periods presented were as follows:


	Year Ended December 31,
	2023			2022
Expected term (years)		6.10			6.10
Expected volatility		70.0	%		70.4	%
Risk-free interest rate		3.87	%		2.01	%
Expected dividend yield		0.0	%		0.0	%

Stock-Based Compensation Expense for Equity Awards Reported in Statements of Operations and Comprehensive Loss

Stock-based compensation expense for all equity awards has been reported in the statements of operations and comprehensive loss as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	6,152	$	4,827
General and administrative		6,936		6,098
Total	$	13,088	$	10,925

2021 Employee Stock Purchase Plan

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Weighted-Average Assumptions Used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants


	Year Ended December 31,
	2023			2022
Expected term (years)		1.51			1.26
Expected volatility		85.4	%		78.0	%
Risk-free interest rate		4.44	%		2.78	%
Expected dividend yield		0.0	%		0.0	%

- Definition

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

+ References

+ Details

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Summary of Maturities of Operating Lease Liabilities, Related Party

Maturities of operating lease liabilities, related party as of December 31, 2023 are as follows (in thousands):


2024	$	918
2025		945
2026		973
2027		663
Thereafter		—
Total future minimum lease payments		3,499
Less: Present value adjustment		(449	)
Operating lease liabilities, related party	$	3,050

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (66,862)	$ (63,308)
Reconciliation of net loss to net cash used in operating activities:
Depreciation	537	406
Stock-based compensation	13,088	10,925
Amortization of premiums on investment securities, net	(6,084)	(1,396)
Non-cash lease expense	33	60
Other		4
Change in operating assets and liabilities:
Prepaid expense and other assets	1,974	(3,393)
Accounts payable and other liabilities	(1,246)	5,400
Accounts payable and other liabilities related-party		(15)
Net cash used in operating activities	(58,560)	(51,317)
Cash flows from investing activities
Purchases of investment securities	(224,703)	(312,998)
Proceeds from maturities of investment securities	277,495	92,890
Proceeds from sale of asset		39
Purchases of property and equipment	(256)	(918)
Net cash provided by (used) in investing activities	52,536	(220,987)
Cash flows from financing activities
Proceeds from the exercise of stock options	419	323
Issuance of common stock through employee stock purchase plan	305	339
Payment of deferred issuance costs		(427)
Net cash provided by financing activities	724	235
Net decrease in cash and cash equivalents	(5,300)	(272,069)
Cash and cash equivalents at beginning of period	26,500	298,569
Cash and cash equivalents at end of period	21,200	26,500
Supplemental disclosures
Initial recognition of operating lease right-of-use asset and operating lease liability		$ 590
Purchases of property and equipment included in accrued expenses	$ 25

Stockholders Deficit (Tables)

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Summary of Restricted Shares of Common Stock and Unvested Stock Liability


	Shares			Liability
Balance at December 31, 2021		239,826		$	23
Vested shares		(192,108	)		(14	)
Balance at December 31, 2022		47,718			9
Vested shares		(47,718	)		(9	)
Balance at December 31, 2023		—		$	—

Related Party Transactions

12 Months Ended

Dec. 31, 2023

Related Party Transactions

13. Related Party Transactions

Lease Agreement

In February 2021, the Company entered into the Lease with Crossing Holdings, LLC to rent laboratory and office space. In March 2022, the Company entered into the Lease Amendment with Crossing Holdings, LLC amending the Lease for additional space in the same building. Dr. Pratik Shah and entities that he controls are the sole members of Crossing Holdings, LLC.

Expenses recognized by the Company under the Lease and Lease Amendment during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	845	$	780
General and administrative		298		290
Total expenses	$	1,143	$	1,070

Consulting Agreements

In January 2019, the Company entered into an agreement with the Marlinspike Group, LLC (“Marlinspike Group”) for research support, management, and business consulting services (the “2019 Consulting Agreement”). Further, Marlinspike Group provides the use of approximately 2,120 square feet of its office space in Carlsbad, California to the Company on an as-available basis from time to time pursuant to the agreement. The Company’s Chief Executive Officer and Chairperson of its board of directors is an executive officer of Marlinspike Group.

The term of the 2019 Consulting Agreement was for a one-year period, subject to automatic one-month renewals unless terminated upon 14 days’ written notice. In March 2020, the Consulting Agreement was terminated and replaced with an amended consulting agreement (the “2020 Consulting Agreement”), which provides for the similar services and use of office space for a monthly fee of $20,000. Pursuant to the terms of the 2020 Consulting Agreement, it shall remain in effect until otherwise terminated. Termination may occur at any time upon mutual agreement or unilaterally upon 30 days’ written notice. If the Company unilaterally terminates the 2020 Consulting Agreement for any reason other than cause, it would be subject to a $240,000 termination fee. The Company cannot determine when, or if, such a termination will occur and hence has not recorded a liability for the fee.

Expenses recognized by the Company under the 2020 Consulting Agreement during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
General and administrative	$	240	$	240
Total expenses	$	240	$	240

In December 2017, the Company entered into a consulting agreement with Aseem Z. Ansari, Ph.D. Dr. Ansari, a co-founder, provides consulting services and advises on certain research and development activities (the “Research Consulting Agreement”). Pursuant to the Research Consulting Agreement, as amended, Dr. Ansari performed these services for a monthly fee of $15,000. In November 2023, the Company further amended the Research Consulting Agreement, discontinued the monthly fee effective October 1, 2023 and granted Dr. Ansari an option to purchase 100,000 shares of the Company's common stock. The option has a grant date fair value of $1.72 per share and is being expensed to research and development over a four-year service period. During the year ended December 31, 2023, the Company recorded approximately $11,000 in related stock-based compensation expense.

Expenses recognized by the Company under the Research Consulting Agreement during the periods presented were as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	146	$	180
Total expenses	$	146	$	180

The Company had accrued expenses and other current liabilities of zero and $15,000 as of December 31, 2023 and 2022, pursuant to its related party consulting agreements.

- Definition

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

+ References

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

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

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

The Company is subject to taxation in the United States and various state jurisdictions. All of the Company’s tax years are subject to examination by federal and state tax authorities due to the carryforward of unutilized net operating losses and research and development credits. The Company’s policy is to recognize interest and penalties related to income tax matters as tax expense. The Company had no accrued interest or penalties related to income tax matters on its balance sheets at December 31, 2023 or 2022, and has not recognized interest or penalties in its statements of operations and comprehensive loss for the years ended December 31, 2023 and 2022, respectively. Further, the Company is not currently under examination by any federal, state or local tax authority.

At December 31, 2023, the Company had federal and state net operating loss (“NOL”) carryforwards of $68.2 million and $10.9 million, respectively. Federal NOL carryforwards totaling $0.1 million begin to expire in 2037, unless previously utilized. Federal and state NOL carryforwards of $68.2 million and $0.5 million generated after 2017, may be carryforward indefinitely but can only be utilized to offset 80% of future taxable income. State NOL carryforwards totaling $10.4 million begin to expire in 2037, unless previously utilized. In addition, the Company has federal and state research and development (“R&D”) credit carryforwards totaling $6.9 million and $2.3 million, respectively. The federal R&D credit carryforwards will begin to expire in 2038 unless previously utilized. The state R&D credit carryforwards do not expire.

Utilization of the Company’s NOL and R&D credit carryforwards may be subject to substantial annual limitations in the event a cumulative ownership change has occurred, or that could occur in the future, as required by Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”). In general, an “ownership change,” as defined by Section 382 of the Code, results from a transaction, or series of transactions over a three-year period, resulting in an ownership change of more than 50% of the outstanding common stock of a company by certain stockholders or public groups. Such an ownership change may limit the amount of NOL and R&D credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company completed a study to assess whether an ownership change had occurred from the Company's formation through December 31, 2021. Based upon the study, the Company determined that it had experienced multiple ownership changes during 2020, causing the annual utilization of the NOL and credit carryforwards to be limited. The Company does not believe any of the NOL and credit carryforwards generated through December 31, 2023 would expire solely as a result of annual limitations on the utilization of those attributes. If ownership changes occur in the future, the amount of remaining tax attribute carryforwards available to offset taxable income and income tax expense in future years may be restricted or eliminated. If eliminated, the related asset would be removed from deferred tax assets with a corresponding reduction in the valuation allowance. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, will not impact the Company’s effective tax rate.

Significant components of the Company's net deferred tax assets at December 31, 2023 and 2022 were as follows (in thousands):


	December 31, 2023			December 31, 2022
Deferred tax assets:
Net operating losses	$	15,074		$	12,240
Capitalized research costs		16,635			8,396
Research and development credits		6,996			3,274
Lease liability		641			776
Stock-based compensation		3,255			1,740
Other		810			1,519
Total gross deferred tax assets		43,411			27,945
Valuation allowance		(42,436	)		(26,777	)
Total deferred tax assets		975			1,168
Deferred tax liabilities:
Right of use asset		(618	)		(759	)
Other		(357	)		(409	)
Total deferred tax liabilities		(975	)		(1,168	)
Net deferred tax assets	$	—		$	—

A reconciliation of the Company's income tax expense (benefit) to the amount computed by applying the federal statutory income tax rate for the periods presented were as follows (in thousands):


	December 31, 2023			December 31, 2022
Expected tax benefit at federal statutory rate	$	(14,042	)	$	(13,295	)
State income taxes, net of federal benefit		(37	)		(15	)
Research and development credits		(3,722	)		(2,075	)
Stock-based compensation		906			697
Other		515			(200	)
Change in valuation allowance		16,380			14,888
Provision for income taxes	$	—		$	—

The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination by tax authorities. The Company does not expect that there will be a significant change in the unrecognized tax benefits over the next twelve months. Further, due to the existence of the valuation allowance, future changes in the Company's unrecognized tax benefits will not impact the effective tax rate.

The following table summarizes the changes to the Company's unrecognized tax benefits for the periods presented (in thousands):


	December 31, 2023		December 31, 2022
Balance at beginning of period	$	929	$	418
Increase related to prior year tax positions		87		—
Increase to current year tax positions		783		511
Balance at end of period	$	1,799	$	929

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2023	Mar. 14, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	DSGN
Entity Registrant Name	Design Therapeutics, Inc.
Entity Central Index Key	0001807120
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		56,494,271
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Entity File Number	001-40288
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-3929248
Entity Address, Address Line One	6005 Hidden Valley Road
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Carlsbad
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92011
City Area Code	858
Local Phone Number	293-4900
Document Transition Report	false
Document Annual Report	true
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 163,518,409
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	Portions of the registrant's definitive proxy statement for its 2024 Annual Meeting of Stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission no later than April 29, 2024, are incorporated by reference into Part III of this Annual Report on Form 10-K

Investment Securities - Summary of Available-for-Sale Investments in an Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Market Value, Less than 12 Months	$ 65,344	$ 217,710
Unrealized Losses, Less than 12 Months	(132)	(2,108)
Estimated Fair Market Value, 12 Months or Greater	60,908	66,551
Unrealized Losses, 12 Months or Greater	(304)	(1,261)
Estimated Fair Market Value	126,252	284,261
Unrealized Losses	(436)	(3,369)
Certificates of deposit
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Market Value, Less than 12 Months	8,514	2,648
Unrealized Losses, Less than 12 Months	(14)	(47)
Estimated Fair Market Value, 12 Months or Greater	1,456	2,824
Unrealized Losses, 12 Months or Greater	(14)	(43)
Estimated Fair Market Value	9,970	5,472
Unrealized Losses	(28)	(90)
U.S. Treasury securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Market Value, Less than 12 Months	44,346	187,570
Unrealized Losses, Less than 12 Months	(102)	(1,890)
Estimated Fair Market Value, 12 Months or Greater	51,979	63,727
Unrealized Losses, 12 Months or Greater	(263)	(1,218)
Estimated Fair Market Value	96,325	251,297
Unrealized Losses	(365)	(3,108)
U.S. Government agency securities
Debt Securities, Available-for-Sale [Line Items]
Estimated Fair Market Value, Less than 12 Months	12,484	27,492
Unrealized Losses, Less than 12 Months	(16)	(171)
Estimated Fair Market Value, 12 Months or Greater	7,473
Unrealized Losses, 12 Months or Greater	(27)
Estimated Fair Market Value	19,957	27,492
Unrealized Losses	$ (43)	$ (171)

Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accrued expenses and other current liabilities, related party amounts	$ 716	$ 640
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	56,473,598	55,943,314
Common stock, shares outstanding	56,473,598	55,895,596

Leases - Summary of Maturities of Operating Lease Liabilities, Related Party (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 918
2025	945
2026	973
2027	663
Total future minimum lease payments	3,499
Less: Present value adjustment	(449)
Operating lease liabilities, related party	$ 3,050

Statements of Operations - USD ($) $ in Thousands	12 Months Ended
Statements of Operations - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development (including related party amounts of $991 and $960, respectively)	$ 57,063	$ 48,613
General and administrative (including related party amounts of $538 and $530, respectively)	21,127	18,980
Total operating expenses	78,190	67,593
Loss from operations	(78,190)	(67,593)
Other income, net	11,328	4,285
Net loss	$ (66,862)	$ (63,308)
Net loss per share, basic	$ (1.19)	$ (1.14)
Net loss per share, diluted	$ (1.19)	$ (1.14)
Weighted-average shares of common stock outstanding, basic	55,984,670	55,707,517
Weighted-average shares of common stock outstanding, diluted	55,984,670	55,707,517

Stock-Based Compensation - Weighted-Average Assumptions Used in Black-Scholes Option Pricing Model to Determine Fair Value of Stock Option Grants (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 years 1 month 6 days	6 years 1 month 6 days
Expected volatility	70.00%	70.40%
Risk-free interest rate	3.87%	2.01%
Expected dividend yield	0.00%	0.00%
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	1 year 6 months 3 days	1 year 3 months 3 days
Expected volatility	85.40%	78.00%
Risk-free interest rate	4.44%	2.78%
Expected dividend yield	0.00%	0.00%

- Definition

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

+ References

+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. Fair Value Measurements

Accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. 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 that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level 1: Observable inputs such as quoted prices in active markets.

Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The carrying value of the Company’s cash, accounts payable and accrued liabilities are considered to be representative of their respective fair values due to the short-term nature of those instruments. The Company’s investment securities, which may include money market accounts, money market funds, certificates of deposits, U.S. Treasury securities, and high quality, marketable debt instruments of corporations and government sponsored enterprises, are measured at fair value in accordance with the fair value hierarchy. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis and no transfers between levels have occurred during the periods presented.

The following table summarizes the Company’s financial instruments measured at fair value on a recurring basis at December 31, 2023 and 2022 (in thousands):


	Fair Value Measurement at End of Period Using:
			Quoted Prices
			In Active
			Markets		Significant
			For		Other		Significant
			Identical		Observable		Unobservable
			Assets		Inputs		Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
As of December 31, 2023:
Assets:
Money market funds(1)	$	19,619	$	19,619	$	—	$	—
Certificates of deposit		14,336		14,336		—		—
U.S. Treasury securities		221,304		221,304		—		—
U.S. Government agency securities		24,958		—		24,958		—
Total	$	280,217	$	255,259	$	24,958	$	—
As of December 31, 2022:
Assets:
Money market funds(1)	$	20,895	$	20,895	$	—	$	—
Certificates of deposit		7,929		7,929		—		—
U.S. Treasury securities		265,966		265,966		—		—
U.S. Government agency securities		29,992		—		29,992		—
Total	$	324,782	$	294,790	$	29,992	$	—

(1)

Included in cash and cash equivalents on the accompanying balance sheets.

Interest bearing money market accounts and certificates of deposit are valued at amortized cost, which approximates fair value. The carrying value of the Company’s cash, accounts payable and accrued liabilities are considered to be representative of their respective fair values due to the short-term nature of those instruments. The Company’s investment securities, which may include money market accounts, money market funds, certificates of deposits, U.S. Treasury securities, and high quality, marketable debt instruments of corporations and government sponsored enterprises, are measured at fair value in accordance with the fair value hierarchy. The Company obtains the fair value of its available-for-sale debt securities from a professional pricing service. Level II securities are valued using quoted market prices for similar instruments, non-binding market prices that are corroborated by observable market data and include our investments in marketable debt instruments of government sponsored enterprises. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis and no transfers between levels have occurred during the periods 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 + Details

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Accrued interest or penalties	$ 0	$ 0
Recognized interest or penalties	0	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	68,200,000
Net operating loss carryforwards, subject to expiration	100,000
Net operating loss carryforwards, not subject to expiration	$ 68,200,000
Net operating loss carryforward, expiration year	2037
NOL, percent of taxable income	80.00%
Federal \| Research and Development Credit Carryforwards
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 6,900,000
Tax credit carryforwards, expiration year	2038
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 10,900,000
Net operating loss carryforwards, subject to expiration	10,400,000
Net operating loss carryforwards, not subject to expiration	$ 500,000
Net operating loss carryforward, expiration year	2037
State \| Research and Development Credit Carryforwards
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 2,300,000

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Contingencies

From time to time, the Company may become subject to claims or suits arising in the ordinary course of business. The Company accrues a liability for such matters when it is probable that the future expenditures will be made and such expenditures can be reasonably estimated. The Company had no such contingent liabilities as of December 31, 2023 or December 31, 2022.

Related Party Transactions - Summary of Expenses Recognized under Consulting Agreement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Research and development	$ 57,063	$ 48,613
General and administrative	21,127	18,980
Lease Agreement
Related Party Transaction [Line Items]
Research and development	845	780
General and administrative	298	290
Total expenses	1,143	1,070
Research Consulting Agreements
Related Party Transaction [Line Items]
Research and development	146	180
Total expenses	146	180
Marlinspike Group, LLC \| Consulting Agreements
Related Party Transaction [Line Items]
General and administrative	240	240
Total expenses	$ 240	$ 240

Investment Securities (Tables)

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost, Unrealized Gains and Losses, Allowances for Credit Losses and Fair Value of Available-for-Sale Investments Aggregated by Maturity and Security Type

The amortized cost, unrealized gains, unrealized losses, allowances for credit losses and fair value of available-for-sale investments aggregated by maturity and security type at December 31, 2023 and 2022 consisted of the following (in thousands):


		As of December 31, 2023
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	10,488	$	2	$	(23	)	$	—	$	10,467
U.S. Treasury securities	Within 1 year		162,746		70		(349	)		—		162,467
U.S. Government agency securities	Within 1 year		12,499		—		(29	)		—		12,470
Certificates of deposits	1 year to 2 years		3,862		12		(5	)		—		3,869
U.S. Treasury securities	1 year to 2 years		58,441		412		(16	)		—		58,837
U.S. Government agency securities	1 year to 2 years		12,500		2		(14	)		—		12,488
Total		$	260,536	$	498	$	(436	)	$	—	$	260,598

		As of December 31, 2022
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	4,092	$	—	$	(57	)	$	—	$	4,035
U.S. Treasury securities	Within 1 year		200,938		4		(2,182	)		—		198,760
U.S. Government agency securities	Within 1 year		22,663		—		(84	)		—		22,579
Certificates of deposits	1 year to 2 years		3,920		7		(33	)		—		3,894
U.S. Treasury securities	1 year to 2 years		68,130		2		(926	)		—		67,206
U.S. Government agency securities	1 year to 2 years		7,500		—		(87	)		—		7,413
Total		$	307,243	$	13	$	(3,369	)	$	—	$	303,887

Summary of Available-for-Sale Investments in an Unrealized Loss Position

The following tables present available-for-sale investments that were in an unrealized loss position as of December 31, 2023 and 2022, aggregated by security type and length of time in a continuous unrealized loss position (in thousands):


	As of December 31, 2023
	Less than 12 Months					12 Months or Greater					Total
	Estimated					Estimated					Estimated
	Fair					Fair					Fair
	Market		Unrealized			Market		Unrealized			Market		Unrealized
	Value		Losses			Value		Losses			Value		Losses
Certificates of deposits	$	8,514	$	(14	)	$	1,456	$	(14	)	$	9,970	$	(28	)
U.S. Treasury securities		44,346		(102	)		51,979		(263	)		96,325		(365	)
U.S. Government agency securities		12,484		(16	)		7,473		(27	)		19,957		(43	)
Total	$	65,344	$	(132	)	$	60,908	$	(304	)	$	126,252	$	(436	)

	As of December 31, 2022
	Less than 12 Months					12 Months or Greater					Total
	Estimated					Estimated					Estimated
	Fair					Fair					Fair
	Market		Unrealized			Market		Unrealized			Market		Unrealized
	Value		Losses			Value		Losses			Value		Losses
Certificates of deposits	$	2,648	$	(47	)	$	2,824	$	(43	)	$	5,472	$	(90	)
U.S. Treasury securities		187,570		(1,890	)		63,727		(1,218	)		251,297		(3,108	)
U.S. Government agency securities		27,492		(171	)		—		—			27,492		(171	)
Total	$	217,710	$	(2,108	)	$	66,551	$	(1,261	)	$	284,261	$	(3,369	)

Investment Securities - Summary of Amortized Cost, Unrealized Gains and Losses, Allowances for Credit Losses and Fair Value of Available-for-Sale Investments Aggregated by Maturity and Security Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Amortized Cost	$ 260,536	$ 307,243
Debt securities, Unrealized Gains	498	13
Debt securities, Unrealized Losses	(436)	(3,369)
Debt securities, Estimated Fair Value	$ 260,598	$ 303,887
Certificates of Deposit \| Within 1 Year
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	Within 1 year	Within 1 year
Debt securities, Amortized Cost	$ 10,488	$ 4,092
Debt securities, Unrealized Gains	2
Debt securities, Unrealized Losses	(23)	(57)
Debt securities, Estimated Fair Value	$ 10,467	$ 4,035
Certificates of Deposit \| 1 Year to 2 Years
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	1 year to 2 years	1 year to 2 years
Debt securities, Amortized Cost	$ 3,862	$ 3,920
Debt securities, Unrealized Gains	12	7
Debt securities, Unrealized Losses	(5)	(33)
Debt securities, Estimated Fair Value	$ 3,869	$ 3,894
U.S. Treasury Securities \| Within 1 Year
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	Within 1 year	Within 1 year
Debt securities, Amortized Cost	$ 162,746	$ 200,938
Debt securities, Unrealized Gains	70	4
Debt securities, Unrealized Losses	(349)	(2,182)
Debt securities, Estimated Fair Value	$ 162,467	$ 198,760
U.S. Treasury Securities \| 1 Year to 2 Years
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	1 year to 2 years	1 year to 2 years
Debt securities, Amortized Cost	$ 58,441	$ 68,130
Debt securities, Unrealized Gains	412	2
Debt securities, Unrealized Losses	(16)	(926)
Debt securities, Estimated Fair Value	$ 58,837	$ 67,206
U.S. Government agency securities \| Within 1 Year
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	Within 1 year	Within 1 year
Debt securities, Amortized Cost	$ 12,499	$ 22,663
Debt securities, Unrealized Losses	(29)	(84)
Debt securities, Estimated Fair Value	$ 12,470	$ 22,579
U.S. Government agency securities \| 1 Year to 2 Years
Schedule Of Available For Sale Securities [Line Items]
Debt securities, Maturity	1 year to 2 years	1 year to 2 years
Debt securities, Amortized Cost	$ 12,500	$ 7,500
Debt securities, Unrealized Gains	2
Debt securities, Unrealized Losses	(14)	(87)
Debt securities, Estimated Fair Value	$ 12,488	$ 7,413

Investment Securities

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Investment Securities

5. Investment Securities

The Company’s investment policy defines allowable investment securities and establishes guidelines relating to credit quality, diversification, and maturities of its investments to preserve principal and maintain liquidity. The amortized cost, unrealized gains, unrealized losses, allowances for credit losses and fair value of available-for-sale

investments aggregated by maturity and security type at December 31, 2023 and 2022 consisted of the following (in thousands):


		As of December 31, 2023
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	10,488	$	2	$	(23	)	$	—	$	10,467
U.S. Treasury securities	Within 1 year		162,746		70		(349	)		—		162,467
U.S. Government agency securities	Within 1 year		12,499		—		(29	)		—		12,470
Certificates of deposits	1 year to 2 years		3,862		12		(5	)		—		3,869
U.S. Treasury securities	1 year to 2 years		58,441		412		(16	)		—		58,837
U.S. Government agency securities	1 year to 2 years		12,500		2		(14	)		—		12,488
Total		$	260,536	$	498	$	(436	)	$	—	$	260,598

		As of December 31, 2022
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	4,092	$	—	$	(57	)	$	—	$	4,035
U.S. Treasury securities	Within 1 year		200,938		4		(2,182	)		—		198,760
U.S. Government agency securities	Within 1 year		22,663		—		(84	)		—		22,579
Certificates of deposits	1 year to 2 years		3,920		7		(33	)		—		3,894
U.S. Treasury securities	1 year to 2 years		68,130		2		(926	)		—		67,206
U.S. Government agency securities	1 year to 2 years		7,500		—		(87	)		—		7,413
Total		$	307,243	$	13	$	(3,369	)	$	—	$	303,887

The Company reviews its investments at each reporting date to identify and evaluate whether a decline in fair value below the amortized cost basis of available-for-sale securities is due to credit-related factors and determines if such unrealized losses are the result of credit losses that require impairment. Factors considered in determining whether an unrealized loss is the result of a credit loss or other factors include the extent to which the fair value is less than the cost basis, any changes to the rating of the security by a rating agency, the financial condition and near-term prospects of the issuer, any historical failure of the issuer to make scheduled interest or principal payments, any adverse legal or regulatory events affecting the issuer or issuer’s industry, any significant deterioration in economic condition and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value.

There were 71 and 77 securities in an unrealized loss position at December 31, 2023 and 2022, respectively. The Company determined that unrealized losses on its available-for-sale investment securities were primarily attributable to changes in interest rates. Each security remained at a high credit quality rating. Further, there had been no adverse conditions noted for any of the issuers and the Company does not intend to sell any of the securities prior to maturity. As such, an allowance for credit losses has not been recognized as of December 31, 2023 or 2022.


	As of December 31, 2023
	Less than 12 Months					12 Months or Greater					Total
	Estimated					Estimated					Estimated
	Fair					Fair					Fair
	Market		Unrealized			Market		Unrealized			Market		Unrealized
	Value		Losses			Value		Losses			Value		Losses
Certificates of deposits	$	8,514	$	(14	)	$	1,456	$	(14	)	$	9,970	$	(28	)
U.S. Treasury securities		44,346		(102	)		51,979		(263	)		96,325		(365	)
U.S. Government agency securities		12,484		(16	)		7,473		(27	)		19,957		(43	)
Total	$	65,344	$	(132	)	$	60,908	$	(304	)	$	126,252	$	(436	)

	As of December 31, 2022
	Less than 12 Months					12 Months or Greater					Total
	Estimated					Estimated					Estimated
	Fair					Fair					Fair
	Market		Unrealized			Market		Unrealized			Market		Unrealized
	Value		Losses			Value		Losses			Value		Losses
Certificates of deposits	$	2,648	$	(47	)	$	2,824	$	(43	)	$	5,472	$	(90	)
U.S. Treasury securities		187,570		(1,890	)		63,727		(1,218	)		251,297		(3,108	)
U.S. Government agency securities		27,492		(171	)		—		—			27,492		(171	)
Total	$	217,710	$	(2,108	)	$	66,551	$	(1,261	)	$	284,261	$	(3,369	)

As of December 31, 2023, the Company held 59 domestic certificates of deposit with amortized costs below the Federal Deposit Insurance Corporation (“FDIC”) insured limit. Accrued interest receivable on available-for-sale investment securities, included in “Prepaid expenses and other current assets” on the Company’s balance sheets, was $1.4 million and $1.1 million at December 31, 2023 and 2022, respectively.

Balance Sheet Details

12 Months Ended

Dec. 31, 2023

Balance Sheet Component [Abstract]

Balance Sheet Details

6. Balance Sheet Details

Prepaid expenses and other current assets consisted of the following (in thousands):


	December 31, 2023		December 31, 2022
Prepaid expenses	$	1,354	$	3,617
Interest receivable		1,432		1,115
Total	$	2,786	$	4,732

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


	December 31, 2023			December 31, 2022
Laboratory equipment	$	1,976		$	1,695
Computer equipment and software		102			102
Furniture and fixtures		521			521
Leasehold improvements		151			151
Construction in progress		—			—
		2,750			2,469
Less accumulated depreciation		(1,059	)		(522	)
Total	$	1,691		$	1,947

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


	December 31, 2023		December 31, 2022
Accrued personnel costs	$	4,034	$	3,543
Accrued research and development costs		2,350		2,983
Current portion of operating lease liability, related party		716		640
Accrued other		582		585
Total	$	7,682	$	7,751

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefit Plans	14. Employee Benefit Plans The Company maintains a retirement plan, which is qualified under section 401(k) of the Internal Revenue Code of 1986, as amended, for the Company's U.S. employees. The plan allows eligible employees to defer, at the employee's discretion, pretax compensation up to the IRS annual limits. The Company is not required to make matching contributions under the plan; however, in 2022, the Company began making matching contributions. The Company voluntarily contributed $0.5 million and $0.3 million to the plan for the years ended December 31, 2023 and 2022, respectively.

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of Options and Awards Outstanding, Beginning Balance	5,396,719	2,673,775
Number of Options and Awards Outstanding, Granted	5,299,250	3,132,283
Number of Options and Awards Outstanding, Exercised	(444,398)	(226,128)
Number of Options and Awards Outstanding, Canceled/Expired	(1,689,818)	(183,211)
Number of Options and Awards Outstanding, Ending Balance	8,561,753	5,396,719	2,673,775
Number of Options and Awards Outstanding, Vested and expected to vest at December 31, 2023	7,911,753
Number of Options and Awards Outstanding, Exercisable at December 31, 2023	2,296,750
Weighted Average Exercise Price, Beginning Balance	$ 11.64	$ 8.49
Weighted Average Exercise Price, Granted	5.26	13.50
Weighted Average Exercise Price, Exercised	0.94	1.43
Weighted Average Exercise Price, Cancelled/Expired	9.51	9.81
Weighted Average Exercise Price, Ending Balance	8.67	$ 11.64	$ 8.49
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2023	9.18
Weighted Average Exercise Price, Exercisable at December 31, 2023	$ 12.47
Weighted Average Remaining Contractual Term (Years)	8 years 5 months 15 days	8 years 9 months	9 years 1 month 13 days
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest at December 31, 2023	8 years 4 months 9 days
Weighted Average Remaining Contractual Term (Years), Exercisable at December 31, 2023	6 years 11 months 12 days
Aggregate Intrinsic Value	$ 1,115,560	$ 10,533,451	$ 35,343
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2023	1,008,810
Aggregate Intrinsic Value, Exercisable at December 31, 2023	$ 538,297

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Summary of Company's Financial Instruments Measured at Fair Value on a Recurring Basis

The following table summarizes the Company’s financial instruments measured at fair value on a recurring basis at December 31, 2023 and 2022 (in thousands):


	Fair Value Measurement at End of Period Using:
			Quoted Prices
			In Active
			Markets		Significant
			For		Other		Significant
			Identical		Observable		Unobservable
			Assets		Inputs		Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
As of December 31, 2023:
Assets:
Money market funds(1)	$	19,619	$	19,619	$	—	$	—
Certificates of deposit		14,336		14,336		—		—
U.S. Treasury securities		221,304		221,304		—		—
U.S. Government agency securities		24,958		—		24,958		—
Total	$	280,217	$	255,259	$	24,958	$	—
As of December 31, 2022:
Assets:
Money market funds(1)	$	20,895	$	20,895	$	—	$	—
Certificates of deposit		7,929		7,929		—		—
U.S. Treasury securities		265,966		265,966		—		—
U.S. Government agency securities		29,992		—		29,992		—
Total	$	324,782	$	294,790	$	29,992	$	—

(1)

Included in cash and cash equivalents on the accompanying balance sheets.

Balance Sheet Details - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment	$ 2,750	$ 2,469
Less accumulated depreciation	(1,059)	(522)
Total	1,691	1,947
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment	1,976	1,695
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	102	102
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment	521	521
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	$ 151	$ 151

Net Loss Per Share - Schedule of Antidilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net loss per share	8,581,660	5,451,533
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net loss per share	8,561,753	5,396,719
Shares Subject to Repurchase
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net loss per share		47,718
Employee Stock Purchase Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of diluted net loss per share	19,907	7,096

Investment Securities - Additional Information (Details)	Dec. 31, 2023 USD ($) Security	Dec. 31, 2022 USD ($) Security
Investments, Debt and Equity Securities [Abstract]
Number of available-for-sale investment securities in continuous unrealized loss position	71	77
Number of domestic certificates of deposit held	59
Accrued interest receivable on available-for-sale investment securities \| $	$ 1,400,000	$ 1,100,000

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

7. Leases

In February 2021, the Company entered into a lease agreement with Crossing Holdings, LLC to rent approximately 12,370 square feet of laboratory and office space (the “Lease”). Dr. Pratik Shah and entities that he controls are the sole members of Crossing Holdings, LLC. The lease commenced in September 2021 with a term of 72 months and an option to extend the lease term for a period of three years; however, it is not reasonably certain the Company will exercise the option to renew when the lease term ends in 2027, and thus, the incremental term was excluded from the calculation of the ROU asset or lease liability. Lease payments are subject to annual increases of 3% and the Company is responsible for its share of operating expenses and taxes, which are expensed as incurred. In March 2022, the Company entered into an amendment (the “Lease Amendment”) to its Lease with Crossing Holdings, LLC to rent approximately 4,900 square feet of additional office space in the same building. The Lease Amendment commenced in June 2022 and the term of the additional premises under the Lease Amendment will coincide with the term of the Lease and end in 2027. As of December 31, 2023, the weighed-average remaining lease term for the Company's leases was 3.7 years and the weighted-average discount rate used to determine the right-of-use asset and corresponding operating lease liability was 7.37%.

Maturities of operating lease liabilities, related party as of December 31, 2023 are as follows (in thousands):


2024	$	918
2025		945
2026		973
2027		663
Thereafter		—
Total future minimum lease payments		3,499
Less: Present value adjustment		(449	)
Operating lease liabilities, related party	$	3,050

Rent expense was $0.9 million for each of the years ended December 31, 2023 and 2022.