Stockholder's Equity (Tables)

6 Months Ended

Jun. 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		524,583			10.89
Options cancelled		(245,179	)		18.66
Options exercised		(19,489	)		4.51
Balances, June 30, 2020		2,080,075		$	9.87		5.6	$	15,846
Outstanding and expected to vest as of June 30, 2020		2,001,581		$	9.90		5.5	$	15,609
Exercisable as of June 30, 2020		1,606,343		$	10.26		4.6	$	14,242

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:

	June 30,			June 30,
	2020			2019
Expected volatility		78.1	%		111.0	%
Risk-free interest rate		0.8	%		2.5	%
Dividend yield		0.0	%		0.0	%
Expected life (in years)		3.9			6.0