Stockholder's Equity (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity

Activity under the Company’s stock option plan is set forth below:

						Weighted
						Average
				Weighted		Remaining		Aggregate
				Average		Contractual		Intrinsic
	Number of			Exercise		Life		Value
	Shares			Price		(in years)		(in thousands)
Balances, January 1, 2020		1,820,160		$	10.70
Options granted		779,460			9.28
Options cancelled		(284,901	)		17.65
Options exercised		(110,578	)		2.65
Balances, September 30, 2020		2,204,141		$	9.70		6.0	$	4,757
Outstanding and expected to vest as of September 30, 2020		2,100,932		$	9.79		5.9	$	4,756
Exercisable as of September 30, 2020		1,546,264		$	10.61		4.7	$	4,737

Summary of Fair Value of Employee Stock Options

The fair value of employee stock options was estimated using the Black-Scholes model with the following weighted-average assumptions:

	September 30,			September 30,
	2020			2019
Expected volatility		112.3	%		111.0	%
Risk-free interest rate		0.97	%		2.4	%
Dividend yield		0.0	%		0.0	%
Expected life (in years)		6.0			6.0