Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Summary of stock option activity

		Options Outstanding
			Weighted-		Weighted-
	Options and		Average		Average
	Awards		Exercise		Remaining	Aggregate
	Available for	Number of	Price Per		Contractual	Intrinsic
	Grant	Options	Share		Life (years)	Value
						(In thousands)
Balance—December 31, 2019	638,227	1,931,903	$	7.17	6.5	$	188
Authorized	542,452	—
RSUs granted	(469,304)	—
RSUs cancelled/forfeited	56,562	—
Options granted	(894,955)	894,955	$	2.74
Options exercised	—	(223,463)	$	5.23		$	355
Options cancelled/forfeited	306,237	(330,490)	$	7.45
Balance—December 31, 2020	179,219	2,272,905	$	5.58	7.9	$	1,640
Options exercisable—December 31, 2020		1,048,021	$	7.28	6.8	$	13

Schedule of restricted stock unit activity

	RSUs Outstanding
		Weighted-
		Average
	Number of	Grant Date
	Restricted Stock	Fair Value Per
	Units	Share
Balance—December 31, 2019	211,962	$	6.97
Granted	469,304		4.52
Vested	(207,962)		6.10
Cancelled/forfeited	(56,562)		5.18
Balance—December 31, 2020	416,742	$	4.89

Employee

Schedule of fair value assumptions

	Year Ended
	December 31,
	2020		2019
Expected volatility	74.4 - 79.3	%	65.1 - 74.4	%
Risk-free interest rate	0.22 - 1.63	%	1.46 - 2.52	%
Expected term (in years)	6.07 - 6.08		5.3 - 6.1
Dividend yield	—	%	—	%

2016 Employee Stock Purchase Plan

Schedule of fair value assumptions

	Year Ended
	December 31,
	2020		2019
Expected volatility	44.7 - 100.7	%	39.6 - 74.2	%
Risk-free interest rate	0.12 - 1.68	%	1.67 - 2.66	%
Expected term (in years)	0.5 - 1.0		0.5 - 1.0
Dividend yield	—	%	—	%