Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2023

Retirement Benefits [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 2023, is presented below (in thousands, except per share and contractual life data).

	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in Years)
Options outstanding as of December 31, 2022		5,272		$	3.07		7.15
Granted		993		$	1.22
Exercised		(91	)	$	0.43
Forfeited or expired		(119	)	$	2.93
Options outstanding, vested and expected to vest as of March 31, 2023		6,055		$	2.81		7.26
Options exercisable as of March 31, 2023		3,784		$	3.30		6.16

Summary of Restricted Stock Unit

The following table summarizes restricted stock unit (“RSU”) activity for the three months ended March 31, 2023 (in thousands, except per share data):

	Number of Shares		Weighted Average Grant Date Fair Value Per Share
Outstanding as of December 31, 2022		—	$	—
Awarded		403		0.93
Vested and released		—		—
Forfeited/canceled		—		—
Outstanding as of March 31, 2023		403	$	0.93

Stock-based Compensation Expense

Stock-based compensation expense recognized for stock-based awards in the condensed consolidated statements of operations for the three months ended March 31, 2023, and 2022 was as follows (in thousands):

	Three Months Ended March 31,
	2023		2022
Research and development	$	248	$	190
General and administrative		121		150
Total	$	369	$	340