Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total USD ($)	Convertible notes payable USD ($)	Convertible Preferred Stock USD ($)	Convertible Preferred Stock USD ($)	Convertible Preferred Stock USD ($)	Common Stock USD ($)	Common Stock Convertible notes payable	Common Stock Convertible Preferred Stock USD ($)	Additional Paid-In Capital USD ($)	Additional Paid-In Capital Convertible notes payable USD ($)	Additional Paid-In Capital Convertible Preferred Stock USD ($)	Retained Earnings USD ($)	Accumulated Other Comprehensive Income USD ($)
Beginning balance at Dec. 31, 2013	$ 77,732			$ 5,992		$ 3			$ 28,737			$ 42,964	$ 36
Beginning balance, shares at Dec. 31, 2013				24,000,000		31,927,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	55,813											55,813
Other comprehensive income, net of tax	(84)
Issuance of common stock from initial public offering, net of offering costs, shares						6,038,000
Issuance of common stock from initial public offering, net of offering costs	238,904					1			238,903
Shares issued upon conversion					(24,000,000)		1,543,000	24,000,000
Conversion of convertible preferred stock and notes payable into common stock upon initial public offering		66,338	0		(5,992)			3		66,338	5,989
Conversion of notes payable and accrued interest, related party, into common stock upon initial public offering, shares							701,000
Conversion of notes payable and accrued interest, related party, into common stock upon initial public offering	30,153								30,153
Tax benefit for equity incentive plans	844								844
Stock-based compensation	19,569								19,569
Vesting of stock options and restricted stock	3,111								3,111
Exercise of stock options, net of repurchases, shares						216,000
Exercise of stock options, net of repurchases	542								542
Ending balance at Sep. 30, 2014	$ 492,922			$ 0		$ 7			$ 394,186			$ 98,777	$ (48)
Ending balance, shares at Sep. 30, 2014				0		64,425,000