Consolidated Statements of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Earnings (Deficit) [Member]	Accumulated Other Comprehensive Income [Member]
Stockholders' Equity, Beginning of period at Dec. 31, 2011	$ 282,914	$ 38	$ (77,637)	$ 362,154	$ (1,642)	$ 1
Shares of Treasury Stock, Beginning of period at Dec. 31, 2011			(5,054)
Shares of Common Stock, Beginning of period at Dec. 31, 2011		38,236
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,178				16,178
Other comprehensive income	130					130
Shares repurchased (in shares)	(898)		(898)
Stock repurchases	(12,363)		(12,363)
Share-based compensation	9,214			9,214
Issuance of common stock under employee stock plans (in shares)		1,258
Issuance of common stock under employee stock plans	10,191	1		10,190
Tax payments related to restricted stock units	(1,241)			(1,241)
Income tax benefits from employee stock plans	2,527			2,527
Stockholders' Equity, End of period at Dec. 31, 2012	307,550	39	(90,000)	382,844	14,536	131
Shares of Treasury Stock, End of period at Dec. 31, 2012			(5,952)
Shares of Common Stock, Beginning of period at Dec. 31, 2012		39,493
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,979				23,979
Other comprehensive income	40					40
Shares repurchased (in shares)	(885)		(885)
Stock repurchases	(20,962)		(20,962)
Share-based compensation	11,151			11,151
Issuance of common stock under employee stock plans (in shares)		2,349
Issuance of common stock under employee stock plans	26,886	2		26,884
Tax payments related to restricted stock units	(2,223)			(2,223)
Income tax benefits from employee stock plans	2,576			2,576
Stockholders' Equity, End of period at Dec. 31, 2013	348,997	41	(110,962)	421,232	38,515	171
Shares of Treasury Stock, End of period at Dec. 31, 2013	(6,837)		(6,837)
Shares of Common Stock, Beginning of period at Dec. 31, 2013		41,842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	30,518				30,518
Other comprehensive income	(1,532)					(1,532)
Shares repurchased (in shares)	(884)		(884)
Stock repurchases	(24,091)		(24,091)
Share-based compensation	12,785			12,785
Issuance of common stock under employee stock plans (in shares)		1,695
Issuance of common stock under employee stock plans	21,795	2		21,793
Tax payments related to restricted stock units	(3,744)			(3,744)
Income tax benefits from employee stock plans	5,370			5,370
Stockholders' Equity, End of period at Dec. 31, 2014	$ 390,098	$ 43	$ (135,053)	$ 457,436	$ 69,033	$ (1,361)
Shares of Treasury Stock, End of period at Dec. 31, 2014	(7,721)		(7,721)
Shares of Common Stock, Beginning of period at Dec. 31, 2014		43,537