CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2018	$ 1,048,231	$ 702	$ 632,235	$ 863,768	$ (355,857)	$ (92,617)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(20,238)			(20,238)
Other comprehensive income (loss)	(409)					(409)
Stock-based compensation	20,957		20,957
Shares issued and forfeited, net, under stock plans	7,476		(2,395)		9,871
Repurchase of common stock	(631)				(631)
Repurchase of stock-based compensation awards for tax withholdings	(2,809)				(2,809)
Ending balance at Jun. 30, 2019	1,052,577	702	650,797	843,530	(349,426)	(93,026)
Beginning balance at Mar. 31, 2019	1,032,584	702	636,960	837,805	(351,587)	(91,296)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	5,725			5,725
Other comprehensive income (loss)	(1,730)					(1,730)
Stock-based compensation	14,372		14,372
Shares issued and forfeited, net, under stock plans	1,811		(535)		2,346
Repurchase of stock-based compensation awards for tax withholdings	(185)				(185)
Ending balance at Jun. 30, 2019	1,052,577	702	650,797	843,530	(349,426)	(93,026)
Beginning balance at Dec. 31, 2019	1,129,968	702	667,658	930,830	(377,639)	(91,583)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(10,352)			(10,352)
Other comprehensive income (loss)	(6,751)					(6,751)
Stock-based compensation	14,882		14,882
Shares issued and forfeited, net, under stock plans	2,995		(14,986)		17,981
Repurchase of common stock	(28,881)				(28,881)
Repurchase of stock-based compensation awards for tax withholdings	(11,124)				(11,124)
Ending balance at Jun. 30, 2020	1,090,737	702	667,554	920,478	(399,663)	(98,334)
Beginning balance at Mar. 31, 2020	1,067,798	702	656,723	906,403	(398,278)	(97,752)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	14,075			14,075
Other comprehensive income (loss)	(582)					(582)
Stock-based compensation	7,932		7,932
Shares issued and forfeited, net, under stock plans	1,665		2,899		(1,234)
Repurchase of stock-based compensation awards for tax withholdings	(151)				(151)
Ending balance at Jun. 30, 2020	$ 1,090,737	$ 702	$ 667,554	$ 920,478	$ (399,663)	$ (98,334)