Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2010	$ 205,567	$ 106	$ 493,967	$ (1,218)	$ (293,520)	$ 6,232
Balance (in shares) at Dec. 31, 2010		105,906
Increase (Decrease) in Stockholders' Equity
Net income (loss)	5,077				5,077
Foreign currency translation adjustments	(1,465)					(1,465)
Change in pension	10					10
Exercise of stock options	288		288
Exercise of stock options (in shares)		372
Issuance of shares under Employee Stock Purchase Plan	503	1	502
Issuance of shares under Employee Stock Purchase Plan (in shares)		398
Issuance of restricted common shares	(112)		(112)
Issuance of restricted common shares (in shares)		133
Stock-based compensation expense	4,687		4,687
Balance at Dec. 31, 2011	214,555	107	499,332	(1,218)	(288,443)	4,777
Balance (in shares) at Dec. 31, 2011		106,809
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(34,034)				(34,034)
Foreign currency translation adjustments	642					642
Change in pension	(399)					(399)
Exercise of stock options	968	1	967
Exercise of stock options (in shares)		1,148
Issuance of shares under Employee Stock Purchase Plan	390		390
Issuance of shares under Employee Stock Purchase Plan (in shares)		306
Issuance of restricted common shares	(22)		(22)
Issuance of restricted common shares (in shares)		30
Stock-based compensation expense	3,976		3,976
Balance at Dec. 31, 2012	186,076	108	504,643	(1,218)	(322,477)	5,020
Balance (in shares) at Dec. 31, 2012		108,293
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(17,144)				(17,144)
Foreign currency translation adjustments	695					695
Change in pension	24					24
Exercise of stock options	1,669	2	1,667
Exercise of stock options (in shares)		1,511
Issuance of shares under Employee Stock Purchase Plan	436		436
Issuance of shares under Employee Stock Purchase Plan (in shares)		206
Issuance of restricted common shares	(26)		(26)
Issuance of restricted common shares (in shares)		215
Stock-based compensation expense	4,272		4,272
Balance at Dec. 31, 2013	$ 176,002	$ 110	$ 510,992	$ (1,218)	$ (339,621)	$ 5,739
Balance (in shares) at Dec. 31, 2013		110,225