Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2011	$ 299,084	$ 5	$ 259,315	$ 39,787	$ (23)
Balance, shares at Dec. 31, 2011		49,145
Net income	38,957
Unrealized gain (loss) on available-for-sale securities, net of tax	3				3
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances, shares		1,869
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances	3,154	0	3,154
Issuance of Common Stock Related to Business Acquisition	0
Issuance of restricted stock upon early exercise of options, shares		70
Vesting of stock options early exercised	105	0	105
Stock-based compensation	10,644		10,644
Tax benefit of equity award deductions	8,317		8,317
Other	(5)		(5)
Balance at Dec. 31, 2012	360,259	5	281,530	78,744	(20)
Balance, shares at Dec. 31, 2012		51,084
Net income	40,783
Unrealized gain (loss) on available-for-sale securities, net of tax	68				68
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances, shares		1,618
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances	5,223	0	5,223
Issuance of Common Stock Related to Business Acquisition	0
Vesting of stock options early exercised	66	0	66
Stock-based compensation	16,192		16,192
Tax benefit of equity award deductions	3,088		3,088
Repurchase of common stock, shares	(10)
Tax withholdings related to net share settlements of restricted stock units	(756)		(756)
Balance at Dec. 31, 2013	424,923	5	305,343	119,527	48
Balance, shares at Dec. 31, 2013		52,692
Net income	39,341			39,341
Unrealized gain (loss) on available-for-sale securities, net of tax	(156)				(156)
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances, shares	623	1,188
Issuance of common stock upon exercise of stock options, vesting of restricted stock units and other common stock issuances	3,163		3,163
Issuance of Common Stock Related to Business Acquisition, Shares		182
Issuance of Common Stock Related to Business Acquisition	3,156		3,156
Stock-based compensation	17,747		17,747
Tax benefit of equity award deductions	1,799		1,799
Tax withholdings related to net share settlements of restricted stock units	4,928		4,928
Balance at Dec. 31, 2014	$ 485,045	$ 5	$ 326,280	$ 158,868	$ (108)
Balance, shares at Dec. 31, 2014		54,062