Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Key Assumptions Used for Black-Scholes Option-pricing Model to Estimate the Fair Value of Stock Options

The key assumptions used to apply this pricing model during the nine months ended September 30, 2021 and 2020, were as follows:

	Nine Months Ended September 30,
	2021			2020
Risk free interest rate		0.76	%		0.91	%
Expected term (in years)		6.05			6.06
Expected dividend yield		0	%		0	%
Expected volatility of underlying common stock		75	%		71	%

Summary of Stock Option Activity

The following table summarizes the stock option activity under the 2018 Plan and 2021 Plan:

	Stock Options			Weighted Average Exercise Price		Weighted Average Remaining Life (in Years)		Intrinsic Value (in thousands)
Outstanding January 1, 2021		1,445,426		$	2.62		8.74	$	3,799
Granted		1,882,441			8.80
Exercised		(108,657	)		2.18
Canceled		(128,361	)		4.82
Outstanding September 30, 2021		3,090,849		$	6.40		8.91	$	9,452
Options vested or expected to vest as of September 30, 2021		3,090,849		$	6.40		8.91	$	9,452
Stock options exercisable as of September 30, 2021		558,385		$	2.44		7.76	$	3,302

Summary of Restricted Common Stock Activity

A summary of the activity for the nine months ended September 30, 2021 is as follows:

	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock as of January 1, 2021		438,280			-
Vested		(233,767	)		-
Unvested restricted stock as of September 30, 2021		204,513			-

Summary of Stock-based Compensation Expense

Stock-based compensation expense was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	270	$	61	$	626	$	173
General and administrative		615		67		1,106		192
Total stock-based compensation expense	$	885	$	128	$	1,732	$	365