Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-based compensation expense

Stock-based compensation expense recorded in the condensed consolidated statements of operations and comprehensive loss is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2023		2022		2023		2022
Research and development expenses	$	1,601	$	1,158	$	4,317	$	2,836
General and administrative expenses	1,795		1,549		4,953		4,177
Total	$	3,396	$	2,707	$	9,270	$	7,013

Schedule of assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted

The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted during the nine months ended September 30, 2023 and 2022:

	September 30, 2023		September 30, 2022
Risk‑free interest rate	4.09	%	2.11	%
Expected volatility	72	%	71	%
Expected dividend yield	—		—
Expected term (in years)	6.02		6.04

Summary of the stock option activity

The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2023:

	Number of Shares	Weighted‑ Average Exercise Price
Outstanding as of December 31, 2022	5,028,850	$	10.95
Granted	799,144	13.79
Exercised	(145,149)	5.20
Forfeited	(120,298)	15.16
Outstanding as of September 30, 2023	5,562,547	$	11.40
Exercisable as of September 30, 2023(1)	3,232,149	$	9.20

(1)This represents the number of vested and unvested options exercisable as of September 30, 2023.

Summary of unvested restricted stock

A summary of restricted stock activity during the nine months ended September 30, 2023 is as follows:

	Shares	Weighted‑ Average Grant‑Date Fair Value
Unvested as of December 31, 2022	463,964	$	12.26
Granted	890,647	$	14.22
Vested	(138,361)	$	12.30
Forfeited	(36,945)	$	12.27
Unvested as of September 30, 2023	1,179,305	$	13.74