CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock and Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock
Beginning balance (in shares) at Dec. 31, 2016		35,555,562			6,638,003
Beginning balance at Dec. 31, 2016	$ 55,340	$ 221,098	$ 115	$ (119,329)	$ (46,544)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(45,291)			(45,291)
Unrealized loss on available-for-sale securities, net of taxes	$ (16)		(16)
Stock repurchase (in shares)	48,687				48,687
Stock repurchase	$ (328)				$ (328)
Exercise of stock options, net of shares withheld for employee taxes (in shares)		70,608
Exercise of stock options, net of shares withheld for employee taxes	518	$ 518
Release of restricted stock units and awards (in shares)		275,598
Release of restricted stock units and awards	2,661	$ 2,661
Issuance of stock for ESPP purchase (in shares)		48,750
Issuance of stock for ESPP purchase	328	$ 328
Stock based compensation	3,441	$ 3,441
Ending balance (in shares) at Dec. 31, 2017		35,950,518			6,686,690
Ending balance at Dec. 31, 2017	9,657	$ 228,046	99	(171,616)	$ (46,872)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	54,343			54,343
Unrealized loss on available-for-sale securities, net of taxes	$ 17		17
Stock repurchase (in shares)	0
Exercise of stock options, net of shares withheld for employee taxes (in shares)		1,452,306			136,457
Exercise of stock options, net of shares withheld for employee taxes	$ 7,987	$ 9,465			$ (1,478)
Release of restricted stock units and awards (in shares)		222,985
Release of restricted stock units and awards	2,806	$ 2,806
Issuance of stock for ESPP purchase (in shares)		26,689
Issuance of stock for ESPP purchase	218	$ 218
Stock based compensation	5,880	$ 5,880
Ending balance (in shares) at Dec. 31, 2018		37,652,498			6,823,147
Ending balance at Dec. 31, 2018	99,660	$ 246,415	116	(98,521)	$ (48,350)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(20,044)			(20,044)
Unrealized loss on available-for-sale securities, net of taxes	$ 8		8
Stock repurchase (in shares)	387,309				387,309
Stock repurchase	$ (2,741)				$ (2,741)
Exercise of stock options, net of shares withheld for employee taxes (in shares)		173,993
Exercise of stock options, net of shares withheld for employee taxes	1,245	$ 1,245
Release of restricted stock units and awards (in shares)		776,552
Release of restricted stock units and awards	0	$ 0
Issuance of stock for ESPP purchase (in shares)		21,741
Issuance of stock for ESPP purchase	165	$ 165
Stock based compensation	5,464	$ 5,464
Ending balance (in shares) at Dec. 31, 2019		38,624,784			7,210,456
Ending balance at Dec. 31, 2019	$ 83,757	$ 253,289	$ 124	$ (118,565)	$ (51,091)