Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

A summary of the status of stock options as of December 31, 2019 and September 30, 2020 and changes during the nine months ended September 30, 2020 is presented below:

								Aggregate
				Weighted		Remaining		Intrinsic
				Average		Contractual		Value
	Shares			Exercise Price		Life (in years)		(in thousands)
Outstanding at December 31, 2019		4,618,421		$	9.16	7.5		$	2,525
Granted		1,190,050			7.84
Exercised		(95,647	)		5.32
Cancelled		(163,534	)		10.88
Outstanding at September 30, 2020		5,549,290		$	8.89		7.3	$	6,624
Exercisable at September 30, 2020		3,061,426		$	9.30		6.4	$	3,936

Summary of Status of Restricted Stock Units

A summary of the status of restricted stock units as of December 31, 2019 and September 30, 2020 and changes during the nine months ended September 30, 2020 is presented below:

				Weighted
				Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2019		1,116,358		$	6.75
Granted		816,300			8.05
Vested		(105,912	)		6.88
Forfeited		(132,113	)		7.25
Outstanding at September 30, 2020		1,694,633		$	7.33

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,
	2020			2019			2020			2019
Weighted-average risk-free interest rate		0.46	%		1.88	%		1.29	%		2.46	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected option term (in years)		5.89			6.08			5.99			6.02
Volatility		79.96	%		89.91	%		78.26	%		91.49	%

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,
	2020		2019		2020		2019
Research and development	$	1,229	$	874	$	3,459	$	2,490
General and administrative		1,494		1,515		4,450		4,133
Total stock-based compensation expense	$	2,723	$	2,389	$	7,909	$	6,623