Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

Summary of Weighted-Average Assumptions Used Principally in Determining Fair Value of Options Granted

The weighted-average assumptions used principally in determining the fair value of options granted were as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
Fair value of common stock	$	13.12		$	2.87		$	20.27		$	2.73
Expected term (in years)		6.0			6.0			6.0			6.0
Expected volatility		76.0	%		77.2	%		78.8	%		77.0	%
Risk-free interest rate		0.9	%		0.4	%		0.8	%		0.4	%
Dividend yield		—			—			—			—

Summary of Stock-Based Compensation Expense

Stock-based compensation expense was allocated as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2021		2020		2021		2020
Research and development	$	630	$	254	$	1,621	$	374
General and administrative		524		229		1,491		374
Total stock-based compensation expense	$	1,154	$	483	$	3,112	$	748