Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock
Beginning balance at Dec. 31, 2015	$ 520,259	$ 994	$ 533,746	$ (58,276)	$ 171,788	$ (127,993)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,300)				(13,300)
Employee stock options, restricted stock and employee stock purchase plan	289	(1)	(248)			538
Stock-based compensation expense	2,974		2,974
Income tax effect, net, of employee stock related activity	(13)		(13)
Foreign currency translation	4,634			4,634
Ending balance at Mar. 31, 2016	514,843	993	536,459	(53,642)	158,488	(127,455)
Beginning balance at Dec. 31, 2016	500,543	998	558,966	(63,208)	129,873	(126,086)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(983)				(983)
Employee stock options, restricted stock and employee stock purchase plan	442	1	202		(186)	425
Stock-based compensation expense	2,836		2,836
Foreign currency translation	2,555			2,555
Ending balance at Mar. 31, 2017	$ 505,393	$ 999	$ 562,004	$ (60,653)	$ 128,704	$ (125,661)