Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 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 Company’s equity incentive plan and employee stock purchase plan was recorded in the statements of operations and allocated as follows (in thousands):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2023		2022		2023		2022
Research and development	$	1,778	$	1,186	$	4,902	$	3,451
General and administrative		1,820		1,545	$	5,365		4,169
Total stock-based compensation expense	$	3,598	$	2,731	$	10,267	$	7,620

As of September 30, 2023, there was $30.1 million of total unrecognized stock-based compensation expense which is expected to be recognized over a weighted-average period of 2.4 years.

Summary of Stock Option Activity

The following table summarizes stock option activity:

	Outstanding Options
	Shares			Weighted- Average Exercise		Weighted- Average Remaining Contractual Term (Years)
Balance, December 31, 2022		5,341,975		$	8.79		8.6
Granted		2,304,295			10.54
Exercised		(99,554	)		7.65
Cancelled		(231,500	)		12.39
Balance, September 30, 2023		7,315,216			9.24		8.4
Exercisable, September 30, 2023		3,037,500		$	8.82		7.9

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

The Company estimates the fair value of stock options using the Black-Scholes option pricing model and the fair value of these stock options was estimated using the following weighted-average assumptions:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2023			2022			2023			2022
Expected term in years		6.0			6.0			6.0			6.0
Expected volatility		82	%		96	%		80	%		94	%
Risk-free interest rate		4.4	%		3.6	%		3.7	%		3.0	%
Dividend yield		—			—			—			—
Weighted average fair value of share-based awards granted	$	12.59		$	8.81		$	7.47		$	4.91

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		(135,237	)		4.02
Forfeited		—			—
Balance, September 30, 2023		156,999		$	4.05