Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Retained earnings [Member]
Beginning Balance at Dec. 31, 2013	$ 223,779	$ 34	$ 201,021	$ 18	$ 22,706
Beginning Balance, shares at Dec. 31, 2013		34,073
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under equity compensation plans	5,471	$ 0	5,471	0
Issuance of common stock under equity compensation plans, shares		428
Issuance of common stock under equity compensation plans	29,758		29,758	0	0
Tax impact from the issuance of convertible senior notes	(11,362)		(11,362)
Tax impact from the issuance of convertible senior notes	6,442		6,442
Stock-based compensation expense	(1,956)		(1,956)
Repurchase of common stock, shares		(68)
Repurchases of common stock	(47)			(47)
Net loss	(7,074)				(7,074)
Ending Balance at Dec. 31, 2014	245,011	$ 34	229,374	(29)	15,632
Ending Balance, shares at Dec. 31, 2014		34,433
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under equity compensation plans	3,318	$ 0	3,318
Issuance of common stock under equity compensation plans, shares		308
Tax impact from the issuance of convertible senior notes	6,791		6,791
Convertible senior notes, equity portion, net of tax and issuance costs	571		571
Stock-based compensation expense	(30,934)	$ 1	(30,933)
Repurchase of common stock, shares		(1,418)
Repurchases of common stock	(2)			(2)
Net loss	(6,079)				(6,079)
Ending Balance at Dec. 31, 2015	218,676	$ 33	209,121	(31)	9,553
Ending Balance, shares at Dec. 31, 2015		33,323
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under equity compensation plans	9,365		9,365
Issuance of common stock under equity compensation plans, shares		755
Tax impact from the issuance of convertible senior notes	7,134		7,134
Stock-based compensation expense	(20,168)	$ 0	(20,168)
Repurchase of Convertible Senior Notes	(547)
Repurchase of common stock, shares		(1,181)
Repurchases of common stock	(22)			(22)
Net loss	(13,808)				(13,808)
Ending Balance at Dec. 31, 2016	$ 200,630	$ 33	$ 204,905	$ (53)	$ (4,255)
Ending Balance, shares at Dec. 31, 2016		32,897