Stock incentive plans (Tables)

6 Months Ended

Jun. 30, 2022

Stock incentive plans

Allocation of stock-based compensation expenses

Non-cash stock-based compensation expense recognized in the accompanying condensed statements of operations relating to stock options, restricted stock awards, and restricted stock units for the three and six months ended June 30, 2022 and 2021, was as follows (in thousands):

	Three months ended				Six months ended
	June 30,				June 30,
	2022		2021		2022		2021
Research and development	$	444	$	676	$	819	$	1,413
General and administrative		1,837		1,802		3,812		3,720
Total stock‑based compensation expense	$	2,281	$	2,478	$	4,631	$	5,133

Summary of stock option activity

The table below summarizes activity related to stock options (in thousands, except per share amounts):

				Weighted‑
		Weighted‑		average
		average		remaining	Aggregate
		exercise		contractual	intrinsic
Options	Shares	price		term	value
Outstanding, December 31, 2021	10,713	$	5.36	8.07	$	718
Granted	2,286		2.98
Exercised	—		—
Forfeited and canceled	(383)		3.97
Outstanding, June 30, 2022	12,616	$	4.97	7.82	$	19
Vested and expected to vest at June 30, 2022	12,616	$	4.97	7.82	$	19
Exercisable at June 30, 2022	6,282	$	6.64	6.61	$	2