Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in Capital	Accumulated Deficit
Beginning balance (shares) at Dec. 31, 2019		58,877,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	32,749	32,000
Release of stock awards (shares)		300,000
Taxes paid related to net share settlement of equity awards (shares)		(84,000)
Ending balance (shares) at Jun. 30, 2020		59,125,000
Beginning balance at Dec. 31, 2019	$ 105,517	$ 6	$ 447,920	$ (342,409)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options	197		197
Employee stock-based compensation	4,104		4,104
Non-employee stock-based compensation	4		4
Taxes paid related to net share settlement of equity awards	(1,040)		(1,040)
Net income (loss)	(13,996)			(13,996)
Ending balance at Jun. 30, 2020	94,786	$ 6	451,185	(356,405)
Beginning balance (shares) at Mar. 31, 2020		59,017,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)		27,000
Release of stock awards (shares)		81,000
Ending balance (shares) at Jun. 30, 2020		59,125,000
Beginning balance at Mar. 31, 2020	99,066	$ 6	449,121	(350,061)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options	158		158
Employee stock-based compensation	1,935		1,935
Non-employee stock-based compensation	4		4
Taxes paid related to net share settlement of equity awards	(33)		(33)
Net income (loss)	(6,344)			(6,344)
Ending balance at Jun. 30, 2020	$ 94,786	$ 6	451,185	(356,405)
Beginning balance (shares) at Dec. 31, 2020		64,283,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	212,631	213,000
Release of stock awards (shares)		181,000
Taxes paid related to net share settlement of equity awards (shares)		(54,000)
Ending balance (shares) at Jun. 30, 2021		64,623,000
Beginning balance at Dec. 31, 2020	$ 170,103	$ 6	536,516	(366,419)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options	1,678		1,678
Employee stock-based compensation	5,405		5,405
Non-employee stock-based compensation	126		126
Taxes paid related to net share settlement of equity awards	(1,206)		(1,206)
Net income (loss)	(13,333)			(13,333)
Ending balance at Jun. 30, 2021	162,773	$ 6	542,519	(379,752)
Beginning balance (shares) at Mar. 31, 2021		64,488,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)		95,000
Release of stock awards (shares)		42,000
Taxes paid related to net share settlement of equity awards (shares)		(2,000)
Ending balance (shares) at Jun. 30, 2021		64,623,000
Beginning balance at Mar. 31, 2021	163,739	$ 6	539,220	(375,487)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options	455		455
Employee stock-based compensation	2,779		2,779
Non-employee stock-based compensation	65		65
Net income (loss)	(4,265)			(4,265)
Ending balance at Jun. 30, 2021	$ 162,773	$ 6	$ 542,519	$ (379,752)