Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Restricted Stock Unit Activity

A summary of the restricted stock unit activity under the Plans for the three months ended March 31, 2023 was as follows:

	Shares			Weighted- Average Grant Date Fair Value
Restricted stock units outstanding as of December 31, 2022		28,212		$	4.78
Granted		270,716		$	2.85
Vested		(7,041	)	$	4.78
Forfeited		(31,271	)	$	2.85
Restricted stock units outstanding as of March 31, 2023		260,616		$	3.01

Summary of Stock Option Activity Under Plans

A summary of the stock option activity under the Plans for the three months ended March 31, 2023 was as follows:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2022		4,311,333		$	7.07		8.2	$	378
Granted		1,424,630			2.75
Exercised		(2,115	)		2.10
Cancelled		(238,022	)		7.02
Outstanding at March 31, 2023		5,495,826		$	5.95		8.5	$	57

Schedule of Fair Value of Stock Option Estimated on Date of Grant Using Black-Scholes Option-Pricing Model in Case of Options Granted to Executive Officers

The fair value of each stock option granted to employees, directors and non-employees was estimated on the date of grant using the Black-Scholes option-pricing model in the case of the options granted to executive officers, with the following weighted-average assumptions for the three months ended March 31:

	Three Months Ended March 31,
	2023			2022
Risk-free interest rate		3.7	%		2.0	%
Expected dividend yield		—	%		—	%
Expected term (in years)		6.0			4.2
Expected volatility		83.3	%		80.8	%

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense included in the Company’s consolidated statements of operations and comprehensive loss was as follows (in thousands):

	Three Months Ended March 31,
	2023		2022
Research and development	$	284	$	227
General and administrative		1,326		617
Total	$	1,610	$	844