Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit
Beginning balance, stockholders' equity at Dec. 31, 2012	$ 43,292	$ 63	$ 652,041	$ 21,007	$ (37,986)	$ (591,833)
Beginnng balance, stockholders' equity (in shares) at Dec. 31, 2012		62,908			(4,181)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(10,975)
Other comprehensive loss, net of tax	(177)			(177)
Shares issued under employee stock plan, net	445		445
Shares issued under employee stock plan, net (in shares)		413
Shares issued under employee stock purchase plan	131		131
Shares issued under employee stock purchase plan (in shares)		63
Stock-based compensation expense	1,433		1,433
Ending balance, stockholders' equity at Dec. 31, 2013	34,149	$ 63	654,050	20,830	$ (37,986)	(602,808)
Ending balance, stockholders' equity (in shares) at Dec. 31, 2013		63,384			(4,181)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,881
Other comprehensive loss, net of tax	(2,659)			(2,659)
Shares issued under employee stock plan, net	307	$ 1	403		$ (97)
Shares issued under employee stock plan, net (in shares)		718			(77)
Shares issued under employee stock purchase plan	181		181
Shares issued under employee stock purchase plan (in shares)		83
Shares issued in connection with public offering, net of offering costs	31,725	$ 14	31,711
Shares issued in connection with public offering, net of offering costs (in shares)		14,082
Stock-based compensation expense	1,526		1,526
Ending balance, stockholders' equity at Dec. 31, 2014	75,110	$ 78	687,871	18,171	$ (38,083)	(592,927)
Ending balance, stockholders' equity (in shares) at Dec. 31, 2014		78,267			(4,258)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	10,315					10,315
Other comprehensive loss, net of tax	(1,882)			(1,882)
Shares issued under employee stock plan, net	1,384	$ 2	1,939		$ (557)
Shares issued under employee stock plan, net (in shares)		1,479			(152)
Shares issued under employee stock purchase plan	317		317
Shares issued under employee stock purchase plan (in shares)		107
Stock-based compensation expense	2,280		2,280
Ending balance, stockholders' equity at Dec. 31, 2015	$ 87,524	$ 80	$ 692,407	$ 16,289	$ (38,640)	$ (582,612)
Ending balance, stockholders' equity (in shares) at Dec. 31, 2015		79,853			(4,410)