Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based Compensation Expense Recognized

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

	Three Months Ended March 31,
	2022		2021
Research and development	$	785	$	260
General and administrative		1,946		714
Total stock-based compensation expense	$	2,731	$	974

Weighted-Average Assumptions used in Estimating Fair Value of each Stock Options using Black-Scholes Option-Pricing Model

The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions:

	Three Months Ended March 31,
	2022			2021
Risk-free interest rate		1.73	%		0.79	%
Expected volatility		92.65	%		89.13	%
Expected term (in years)		6.01			6.17
Expected dividend yield		—			—

Summary of Option Activity Changes in Shares Available for Grant under the 2020 Plan

Changes in shares available for grant under the 2020 Plan during the three months ended March 31, 2022 were as follows:

	Shares Available for Grant
Shares available for grant at December 31, 2021		4,442,315
2020 Plan reserve increase on January 1, 2022		1,868,953
Options and restricted stock units granted		(1,522,614	)
Options and restricted stock units forfeited,    cancelled, or expired		124,835
Shares available for grant at March 31, 2022		4,913,489

Summary of Option Activity under the 2020 Plan

A summary of stock option activity under the 2020 Plan for the three months ended March 31, 2022 was as follows:

	Shares			Weighted- Average Exercise price per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Balance at December 31, 2021		2,270,896		$	12.76	7.22		$	8,306
Granted		1,510,364			10.44
Exercised		(244,981	)		0.86
Forfeited/expired		(110,835	)		17.12
Balance at March 31, 2022		3,425,444		$	12.44		8.88	$	10,137
Expected to vest		2,721,431		$	13.05		9.33	$	6,035
Options exercisable		704,013		$	10.11		7.14	$	4,102

Summary of Stock Options Outstanding and Exercisable under the 2020 Plan

Stock options outstanding and exercisable under the 2020 Plan consisted of the following at March 31, 2022:

Exercise Price ($)	Shares Outstanding		Shares Exercisable
0.16 to 1.35		439,813		312,133
9.91 to 19.94		2,602,710		288,677
20.55 to 29.41		382,921		103,203
Total		3,425,444		704,013

Restricted Stock Units (RSUs)

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Restricted Stock Activity

A summary of RSU activity for the three months ended March 31, 2022 is as follows:

	Share Equivalent			Weighted- Average Grant Date Fair Value
Non-vested at December 31, 2021		361,500		$	15.32
Granted		12,250			10.54
Cancelled		(14,000	)		15.34
Vested		—			—
Non-vested at March 31, 2022		359,750		$	15.15