CONSOLIDATED STATEMENTS OF STOCKHOLDERS DEFICIT (USD $) In Thousands, except Share data	Total	Series G Preferred Stock	Series H Preferred Stock	Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Loss
Temporary Equity, Balance at Dec. 31, 2011		$ 59,059	$ 63,819
Balance at Dec. 31, 2011	(29,280)			35,440	(64,550)	(170)
Temporary Equity, Balance, shares at Dec. 31, 2011		5,391,441	4,124,986
Balance, shares at Dec. 31, 2011				8,398,712
Net income	31,832				31,832
Other comprehensive loss	(25)					(25)
Issuance of common stock from vested restricted stock units, (in shares)				75,992
Issuance of common stock from exercise of stock options	5,391			5,391
Issuance of common stock from exercise of stock options, (in shares)				2,858,784
Repurchase of common stock	(2,683)				(2,683)
Repurchase of common stock, shares				(624,264)
Stock-based compensation expense	4,360			4,360
Excess tax benefit from equity incentive plan activity	297			297
Special dividend	(75,450)				(75,450)
Temporary Equity, Balance at Dec. 31, 2012		59,059	63,819
Balance at Dec. 31, 2012	(65,558)			45,488	(110,851)	(195)
Temporary Equity, Balance, shares at Dec. 31, 2012		5,391,441	4,124,986
Balance, shares at Dec. 31, 2012				10,709,224
Net income	13,147				13,147
Other comprehensive loss	4					4
Issuance of common stock from vested restricted stock units, (in shares)				36,512
Issuance of common stock from exercise of stock options	7,109			7,109
Issuance of common stock from exercise of stock options, (in shares)				5,730,544
Repurchase of common stock	(11,985)				(11,985)
Repurchase of common stock, shares				(1,216,740)
Stock-based compensation expense	5,953			5,953
Excess tax benefit from equity incentive plan activity	15,610			15,610
Special dividend	(357,520)				(357,520)
Balance at Dec. 31, 2013	(393,240)			74,160	(467,209)	(191)
Balance, shares at Dec. 31, 2013				15,259,540
Temporary Equity, Balance at Dec. 31, 2013		59,059	63,819
Temporary Equity, Balance, shares at Dec. 31, 2013		5,391,441	4,124,986
Net income	15,497				15,497
Other comprehensive loss	(123)					(123)
Issuance of common stock from vested restricted stock units, (in shares)				4,250
Issuance of common stock for employee stock purchase plan	3,393			3,393
Issuance of common stock for employee stock purchase plan (in shares)				249,494
Conversion of preferred stock	122,878	(59,059)	(63,819)	122,878
Conversion of preferred stock (in shares)		(5,391,441)	(4,124,986)	38,065,708
Issuance of common stock from exercise of stock options	2,193			2,193
Issuance of common stock from exercise of stock options, (in shares)	1,712,278			1,712,278
Issuance of common stock, net of initial public offering costs	217,796			217,796
Issuance of common stock, net of initial public offering costs (in shares)				15,091,074
Repurchase of common stock	(16,440)				(16,440)
Repurchase of common stock, shares	(490,419)			(571,018)
Stock-based compensation expense	10,660			10,660
Excess tax benefit from equity incentive plan activity	9,663			9,663
Excess tax benefit from initial public offering	1,939			1,939
Special dividend forfeited	25				25
Balance at Dec. 31, 2014	$ (25,759)			$ 442,682	$ (468,127)	$ (314)
Balance, shares at Dec. 31, 2014				69,811,326