Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of Outstanding Stock Options

Total outstanding stock options as of June 30, 2022 was as follows:

	2022
	Number of shares			Weighted average exercise price
Outstanding at beginning of period		5,322,591		$	14.76
Granted		2,883,567		$	14.54
Exercised		(56,503	)	$	4.12
Cancelled or forfeited		(175,252	)	$	19.00
Outstanding at end of period		7,974,403		$	14.66

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

The fair value of stock options, and the assumptions used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted to employees and non-employees were as follows, presented on a weighted average basis:

	Three Months Ended June 30,						Six Months Ended June 30,
	2022			2021			2022			2021
Risk-free interest rate		2.92	%		0.92	%		2.00	%		0.72	%
Expected terms (in years)		5.59			5.59			5.97			5.99
Expected volatility		78.85	%		76.44	%		78.55	%		75.59	%
Expected dividend yield		0.00	%		0.00	%		0.00	%		0.00	%

Schedule of Share-based Compensation Expense

Share-based compensation expense was allocated as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(in thousands)
Research and development	$	2,440	$	1,441	$	4,751	$	2,428
General and administrative		2,305		1,742		4,749		2,812
Total share-based compensation expense	$	4,745	$	3,183	$	9,500	$	5,240

Share-based compensation expense by type of award was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
	(in thousands)
Stock options	$	4,695	$	3,122	$	9,407	$	5,148
ESPP		50		61		93		92
Total share-based compensation expense	$	4,745	$	3,183	$	9,500	$	5,240