Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Stock Option Activity

The following table summarizes stock option activity under our equity incentive plans during the three months ended March 31, 2022:

	Shares Available to Grant			Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)*
Outstanding at December 31, 2021		3,749,339			6,757,591		$	8.57		8.7	$	50,085
Addition to option pool		3,013,157
Options granted		(339,030	)		339,030			10.47
Options exercised		—			(389,855	)		1.61
Options cancelled or forfeited		420,224			(420,224	)		7.04
Outstanding at March 31, 2022		6,843,690			6,286,542		$	9.20		8.7	$	19,821
Exercisable at March 31, 2022					1,555,480		$	4.11		7.1	$	8,617
Vested and expected to vest at March 31, 2022					6,286,542		$	9.20		8.7	$	19,821

*The aggregate intrinsic value is calculated as the difference between the stock option exercise price and the estimated fair value of the underlying common stock at the end of each reporting period referenced above.

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

We estimated the fair value of each employee and non-employee stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions for the three months ended March 31, 2022 and 2021:

	Three Months Ended March 31,
	2022	2021
Volatility	71.7% - 72.0%	76.4% to 76.5%
Expected term (in years)	5.5 to 6.0	6.0 to 6.1
Risk-free interest rate	1.7% to 2.3%	1.1% to 1.2%
Expected dividend yield	0.0%	0.0%

Schedule of Restricted Stock Units Activity (RSUs)

A summary of the status of and change in unvested RSUs as of March 31, 2022 was as follows:

	Number of Shares Underlying Outstanding Restricted Stock		Weighted-Average Grant Date Fair Value per RSU
Unvested, January 1, 2022		-	$	-
Granted		60,000		10.64
Unvested, March 31, 2022		60,000	$	10.64

Schedule of Stock-Based Compensation Expenses Recorded in the Condensed Consolidated Statements of Operations and Comprehensive Loss

We recorded stock-based compensation expense related to employee and non-employee equity-based awards in our condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2022 and 2021 as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	1,100	$	197
General and administrative		1,924		146
Total	$	3,024	$	343

Schedule of Stock-Based Compensation Expense Related to Equity-Based Awards

The above stock-based compensation expense related to the following equity-based awards (in thousands):

	Three Months Ended March 31,
	2022		2021
Stock options	$	2,930	$	343
ESPP		63		-
RSUs		31		-
Total	$	3,024	$	343