Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)

9 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

A summary of the status of stock options as of December 31, 2020 and September 30, 2021 and changes during the nine months ended September 30, 2021 is presented below:

								Aggregate
				Weighted		Remaining		Intrinsic
				Average		Contractual		Value
	Shares			Exercise Price		Life (in years)		(in thousands)
Outstanding at December 31, 2020		5,468,605		$	8.90	7.2		$	13,124
Granted		1,647,000			9.17
Exercised		(20,134	)		7.77
Cancelled		(831,121	)		9.92
Outstanding at September 30, 2021		6,264,350		$	8.84		6.7	$	931
Exercisable at September 30, 2021		3,872,773		$	9.06		5.4	$	931

Summary of Status of Restricted Stock Units

A summary of the status of restricted stock units as of December 31, 2020 and September 30, 2021 and changes during the nine months ended September 30, 2021 is presented below:

				Weighted
				Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2020		1,734,383		$	7.40
Granted		800,454			9.26
Vested		(267,012	)		7.70
Forfeited		(416,863	)		7.92
Outstanding at September 30, 2021		1,850,962		$	8.04

Schedule of Weighted-Average Assumptions used in Black-Scholes Option-Pricing Model

The fair value of each stock option granted was estimated on the date of grant using the Black-Scholes option-pricing model based on the following weighted-average assumptions:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
Weighted-average risk-free interest rate		1.12	%		0.46	%		0.87	%		1.29	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected option term (in years)		6.06			5.89			6.01			5.99
Volatility		81.24	%		79.96	%		81.88	%		78.26	%

Summary of Stock-based Compensation Expense for Stock Options and Restricted Stock Units

The following table summarizes the stock-based compensation expense for stock options and restricted stock units granted to employees and non-employees recorded in the Company’s condensed consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	1,485	$	1,229	$	4,260	$	3,459
General and administrative		611		1,494		3,219		4,450
Total stock-based compensation expense	$	2,096	$	2,723	$	7,479	$	7,909