Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Treasury Stock	Accumulated Deficit
Beginning balance, stockholders' equity at Dec. 31, 2011	$ 60,145	$ 63	$ 650,110	$ 20,472	$ (37,986)	$ (572,514)
Beginnng balance, stockholders' equity (in shares) at Dec. 31, 2011		62,547			(4,181)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(19,319)					(19,319)
Other comprehensive loss, net of tax	535			535
Shares issued under employee stock plan, net	238		238
Shares issued under employee stock plan, net (in shares)		256
Shares issued under employee stock purchase plan	128		128
Shares issued under employee stock purchase plan (in shares)		105
Stock-based compensation expense	1,565		1,565
Ending balance, stockholders' equity at Dec. 31, 2012	43,292	63	652,041	21,007	(37,986)	(591,833)
Ending 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)