Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2018	$ 39,001	$ 1,597	$ 314,907	$ (276,800)	$ (703)
Balance (in shares) at Dec. 31, 2018		159,721
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	7,781	$ 23	7,758
Issuance of common stock (in shares)		2,307
Common stock issued under equity compensation plan, net of shares withheld for taxes	(1,131)	$ 7	(1,138)
Common stock issued under equity compensation plan, net of shares withheld for taxes (in shares)		664
Exercise of options	4,405	$ 25	4,380
Exercise of options (in shares)		2,529
Share-based compensation	6,470		6,470
Net income (loss)	(2,027)			(2,027)
Other comprehensive income (loss)	1				1
Balance at Dec. 31, 2019	54,500	$ 1,652	332,377	(278,827)	(702)
Balance (in shares) at Dec. 31, 2019		165,221
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under equity compensation plan, net of shares withheld for taxes	(1,367)	$ 7	(1,374)
Common stock issued under equity compensation plan, net of shares withheld for taxes (in shares)		676
Exercise of options	1,814	$ 9	1,805
Exercise of options (in shares)		939
Share-based compensation	7,948		7,948
Net income (loss)	56,201			56,201
Other comprehensive income (loss)	19				19
Balance at Dec. 31, 2020	119,115	$ 1,668	340,756	(222,626)	(683)
Balance (in shares) at Dec. 31, 2020		166,836
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under equity compensation plan, net of shares withheld for taxes	(2,841)	$ 10	(2,851)
Common stock issued under equity compensation plan, net of shares withheld for taxes (in shares)		942
Exercise of options	5,182	$ 23	5,159
Exercise of options (in shares)		2,294
Share-based compensation	8,015		8,015
Net income (loss)	46,289			46,289
Other comprehensive income (loss)	(2)				(2)
Balance at Dec. 31, 2021	$ 175,758	$ 1,701	$ 351,079	$ (176,337)	$ (685)
Balance (in shares) at Dec. 31, 2021		170,072