Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of status of stock options and changes during the period

A summary of the status of stock options as of December 31, 2019 and June 30, 2020 and changes during the six months ended June 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		1,136,950			7.79
Exercised		(49,100	)		4.32
Cancelled		(98,214	)		11.76
Outstanding at June 30, 2020		5,608,057		$	8.88		7.6	$	12,864
Exercisable at June 30, 2020		2,921,724		$	9.24		6.6	$	6,342

Summary of status of restricted stock units and changes during the period

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

				Weighted
				Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2019		1,116,358		$	6.75
Granted		729,000			7.88
Vested		(103,462	)		6.86
Forfeited		(28,813	)		7.23
Outstanding at June 30, 2020		1,713,083		$	7.22

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,
	2020			2019			2020			2019
Weighted-average risk-free interest rate		0.36	%		1.97	%		1.33	%		2.47	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected option term (in years)		5.49			5.63			6.00			6.02
Volatility		79.70	%		90.33	%		78.18	%		91.51	%

Summary of stock-based compensation expense for stock options granted to employee and non-employees

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,
	2020			2019			2020		2019
Research and development		$	1,181		$	918	$	2,230		$	1,615
General and administrative			1,546			1,438		2,956			2,619
Total stock-based compensation expense		$	2,727		$	2,356	$	5,186		$	4,234