Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional paid-in capital	Treasury Stock	Accumulated other comprehensive income (loss)	Accumulated deficit	Total
Beginning balance at Dec. 31, 2014	$ 2	$ 497,809	$ (30,767)	$ (76)	$ (352,126)	$ 114,842
Beginning balance (in shares) at Dec. 31, 2014	19,741
Issuance of stock under employee stock awards and other		464				464
Issuance of stock under employee stock awards and other (in shares)	290
Issuance of stock for acquisition holdback	123
Tax withholdings related to vesting of share-based payments		(668)				(668)
Stock-based compensation expense		7,998				7,998
Foreign currency translation adjustment				(15)		(15)
Net loss					(43,501)	(43,501)
Ending balance at Dec. 31, 2015	$ 2	505,603	(30,767)	(91)	(395,627)	79,120
Ending balance (in shares) at Dec. 31, 2015	20,154
Issuance of stock under employee stock awards and other		580				580
Issuance of stock under employee stock awards and other (in shares)	453
Repurchases of common stock to be held in treasury			(4,874)			(4,874)
Repurchases of common stock to be held in treasury (in shares)	(844)
Tax withholdings related to vesting of share-based payments		(1,246)				(1,246)
Stock-based compensation expense		8,202				8,202
Foreign currency translation adjustment				(21)		(21)
Net loss					(2,011)	(2,011)
Ending balance at Dec. 31, 2016	$ 2	513,139	(35,641)	(112)	(397,638)	$ 79,750
Ending balance (in shares) at Dec. 31, 2016	19,763					19,763
Issuance of stock under employee stock awards and other		2,597				$ 2,597
Issuance of stock under employee stock awards and other (in shares)	1,063
Repurchases of common stock to be held in treasury			(65)			(65)
Repurchases of common stock to be held in treasury (in shares)	(10)
Issuance of common stock for acquisitions		1,603				1,603
Issuance of common stock for acquisitions (in shares)	215
Tax withholdings related to vesting of share-based payments		(3,284)				(3,284)
Stock-based compensation expense		8,957				8,957
Foreign currency translation adjustment				95		95
Net loss					(31,133)	(31,133)
Ending balance at Dec. 31, 2017	$ 2	$ 523,012	$ (35,706)	$ (17)	$ (428,771)	$ 58,520
Ending balance (in shares) at Dec. 31, 2017	21,031					21,031