Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

A summary of the status of stock options as of December 31, 2020 and June 30, 2021 and changes during the six months ended June 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		1,231,900			10.63
Exercised		(20,134	)		7.77
Cancelled		(265,341	)		9.57
Outstanding at June 30, 2021		6,415,030		$	9.21		6.9	$	1,297
Exercisable at June 30, 2021		3,971,194		$	9.20		5.8	$	1,290

Summary of Status of Restricted Stock Units

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

				Weighted
				Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2020		1,734,383		$	7.40
Granted		687,554			9.98
Vested		(244,312	)		7.57
Forfeited		(206,670	)		8.00
Outstanding at June 30, 2021		1,970,955		$	8.22

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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Weighted-average risk-free interest rate		0.88	%		0.36	%		0.79	%		1.33	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected option term (in years)		5.46			5.49			5.99			6.00
Volatility		82.05	%		79.70	%		82.10	%		78.18	%

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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	1,451	$	1,181	$	2,775	$	2,230
General and administrative		1,002		1,546		2,608		2,956
Total stock-based compensation expense	$	2,453	$	2,727	$	5,383	$	5,186