Stock-Based Compensation Expense (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	209	$	146	$	436	$	288
General and administrative		898		510		1,515		967
Total	$	1,107	$	656	$	1,951	$	1,255

Schedule of Unrecognized Stock-Based Compensation

The following table summarizes the Company’s unrecognized stock-based compensation as of June 30, 2022:

	As of June 30, 2022
	Unrecognized Expense (in thousands)		Period of Recognition (years)
Restricted stock units	$	184		3.5
Stock options		11,444		2.2
Total	$	11,628

Schedule of Fair Value of Stock Option Estimated on Date of Grant Using Black-Scholes Option-Pricing Model or Monte Carlo Simulation in Case of Executive Options

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, or a Monte Carlo simulation in the case of the Executive Options, with the following weighted-average assumptions:

	Three Months Ended June 30,						Six Months Ended June 30,
	2022			2021			2022			2021
Risk-free interest rate		3.2	%		0.9	%		2.5	%		0.7	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected term (in years)		2.1			5.7			3.3			6.0
Expected volatility		80.6	%		84.7	%		80.7	%		85.3	%

Summary of Restricted Stock Unit Activity

A summary of the restricted stock unit activity under the Plans for the six months ended June 30, 2022 was as follows:

	Shares			Weighted- Average Grant Date Fair Value
Restricted stock units outstanding as of December 31, 2021		—		$	—
Granted		45,483		$	4.79
Vested		(1,302	)	$	4.89
Forfeited		(1,828	)	$	4.78
Restricted stock units outstanding as of June 30, 2022		42,353		$	4.78

Summary of Stock Option Activity Under Plans

A summary of the stock option activity under the Plans for the six months ended June 30, 2022 was as follows:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding December 31, 2021		1,662,861		$	10.34		7.6	$	918
Granted		2,381,749			5.07
Exercised		(2,718	)		2.76
Cancelled		(24,166	)		7.10
Outstanding at June 30, 2022		4,017,726		$	7.24		8.7	$	3,544
Exercisable at June 30, 2022		1,118,220		$	9.79		6.8	$	1,371
Vested and expected to vest at June 30, 2022		4,017,726		$	7.24		8.7	$	3,544