Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [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 March 31,
	2021		2020
Research and development	$	142	$	40
General and administrative		457		94
Total	$	599	$	134

Schedule of Fair Value of Stock Option Estimated on Date of Grant Using Black-Scholes Option-Pricing Model

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, with the following weighted-average assumptions:

	Three Months Ended March 31,
	2021			2020
Risk-free interest rate		0.6	%		1.5	%
Expected dividend yield		—	%		—	%
Expected term (in years)		6.0			6.0
Expected volatility		85.4	%		78.0	%

Summary of Stock Option Activity Under Plans

A summary of the stock option activity under the Plans for the three months ended March 31, 2021 was as follows:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding December 31, 2020		1,428,886		$	10.41		7.7	$	5,165
Granted		365,700			10.75
Exercised		(30,391	)		8.63
Cancelled		(1,590	)		11.70
Outstanding at March 31, 2021		1,762,605		$	10.51		8.1	$	5,540
Exercisable at March 31, 2021		665,936		$	9.39		6.3	$	3,349
Vested and expected to vest at March 31, 2021		1,762,605		$	10.51		8.1	$	5,540