Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense Recorded in Statements of Operations and Allocated

Total stock-based compensation expense related to the 2020 Plan, 2021 Plan, and ESPP was recorded in the statements of operations and allocated as follows (in thousands):

	Year Ended December 31,
	2023		2022		2021
Research and development	$	6,933	$	4,678	$	2,637
General and administrative		7,198		5,658		3,597
Total stock-based compensation expense	$	14,131	$	10,336	$	6,234

As of December 31, 2023, there was $27.6 million of total unrecognized compensation cost related to stock options, restricted stock awards, and ESPP under the Plans. The unrecognized stock-based compensation cost is expected to be recognized over a weighted-average period of 2.3 years.

Summary of Stock Option Activity

The following table summarizes stock option activity:

	Number of Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Balance as of December 31, 2022		5,341,975		$	8.79		8.6	$	6,875
Granted		2,441,795			10.66
Exercised		(125,192	)		7.48
Cancelled		(300,971	)		11.14
Balance as of December 31, 2023		7,357,607		$	9.34		8.1	$	42,071
Options exercisable as of December 31, 2023		3,471,556		$	8.87		7.7	$	20,783

Summary of Fair Value of Stock Options Estimated using Weighted-Average Assumptions

The fair value of stock options was estimated using the following weighted-average assumptions:

	Year Ended December 31,
	2023			2022			2021
Expected term in years		6.0			6.0			6.0
Expected volatility		79.9	%		93.1	%		91.0	%
Risk-free interest rate		3.8	%		3.1	%		1.1	%
Dividend yield		—			—			—
Weighted average fair value of options granted	$	7.57		$	5.25		$	7.28

Summary of Fair Value of ESPP Estimated using Weighted-Average Assumptions

The fair value of ESPP was estimated using the following weighted-average assumptions:

	Year Ended December 31,
	2023			2022			2021
Expected term in years		1.3			1.3			1.3
Expected volatility		80.9	%		95.2	%		91.3	%
Risk-free interest rate		4.9	%		2.5	%		0.3	%
Dividend yield		—			—			—

Summary of Restricted Stock Activity

The following table summarizes the restricted stock activity:

	Number of Restricted Stock Awards			Weighted-Average Grant Date Fair Value
Balance, December 31, 2022		292,236		$	4.04
Granted		—			—
Released		(180,316	)		4.02
Forfeited		—			—
Balance, December 31, 2023		111,920		$	4.06