Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments (Tables)

Stock-Based Payments (Tables)

6 Months Ended

Jun. 30, 2019

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, 2018 and June 30, 2019 and changes during the six months ended June 30, 2019 is presented below:

								Aggregate
				Weighted		Remaining		Intrinsic
				Average		Contractual		Value
	Shares			Exercise Price		Life (in years)		(in thousands)
Outstanding at December 31, 2018		3,732,643		$	9.88	7.9		$	1,694
Granted		1,096,500			6.73
Exercised		(2,300	)		2.93
Cancelled		(85,843	)		11.38
Outstanding at June 30, 2019		4,741,000		$	9.12		8.0	$	6,966
Exercisable at June 30, 2019		1,919,931		$	8.97		6.9	$	3,601

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, 2018 and June 30, 2019 and changes during the six months ended June 30, 2019 is presented below:

				Weighted
				Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2018		—		$	—
Granted		1,133,924			6.77
Vested		—			—
Forfeited		(11,900	)		6.71
Outstanding at June 30, 2019		1,122,024		$	6.77

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,
	2019			2018			2019			2018
Weighted-average risk-free interest rate		1.97	%		2.79	%		2.47	%		2.47	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected option term (in years)		5.63			5.74			6.02			6.03
Volatility		90.33	%		91.16	%		91.51	%		90.37	%

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,
	2019		2018		2019		2018
Research and development	$	918	$	670	$	1,615	$	1,235
General and administrative		1,438		1,074		2,619		2,205
Total stock-based compensation expense	$	2,356	$	1,744	$	4,234	$	3,440