Stock-based compensation (Tables)

3 Months Ended

Mar. 31, 2025

Stock-based compensation

Summary of compensation cost recognized for all stock-based compensation awards

	Three Months Ended
	March 31,
	2025		2024
	(in thousands)
Research and development	$	1,485	$	1,280
General and administrative		2,188		2,293
Total stock-based compensation expense	$	3,673	$	3,573

Summary of stock-based compensation expense by type of award

	Three Months Ended
	March 31,
	2025		2024
	(in thousands)
Stock options	$	2,391	$	2,408
Restricted stock awards and units		1,205		1,090
Employee stock purchase plan awards		77		75
Total stock-based compensation expense	$	3,673	$	3,573

Summary of status and changes in unvested restricted stock

		Weighted
		Average
		Grant Date
		Fair Value
	Units	Per Unit
Unvested as of December 31, 2024	1,649,943	$	7.44
Granted	1,717,311		4.26
Vested	(450,556)		6.47
Forfeited	(67,420)		7.22
Outstanding as of March 31, 2025	2,849,278	$	5.68

Summary of stock option activity

		Weighted		Remaining	Aggregate
		Average		Contractual	Intrinsic
		Exercise		Life	Value
	Shares	Price		(in years)	(in thousands)
Outstanding as of December 31, 2024	8,800,464	$	8.10	7.3		3,462
Granted	1,911,670		4.27
Exercised	(27,613)		2.96
Cancelled or forfeited	(162,438)		7.41
Outstanding as of March 31, 2025	10,522,083	$	7.43	7.4	$	499
Exercisable as of March 31, 2025	5,065,944	$	8.41	6.1	$	406