Stock-Based Compensation - Schedule of the Stock Option Activity and Schedule of Grant Date Fair Value and Grant Date Intrinsic Value (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning (in shares)	1,572,626
Options (in shares)	984,159
Options exercised (in shares)	(652,605)
Options forfeited (in shares)	(22,811)
Options outstanding, ending (in shares)	1,881,369	1,572,626
Options vested and expected to vest (in shares)	1,778,371	1,519,889
Options exercisable (in shares)	786,473	1,223,533
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price - Shares Outstanding, Beginning (in dollars per share)	$ 6.17
Weighted Average Exercise Price - Shares Granted (in dollars per share)	$ 30.39
Weighted Average Exercise Price - Shares Exercised (in dollars per share)	$ 3.62
Weighted Average Exercise Price - Shares Forfeited (in dollars per share)	$ 26.59
Weighted Average Exercise Price - Shares Outstanding, Ending (in dollars per share)	$ 19.30	$ 6.17
Weighted Average Exercise Price - Shares Vested and expected to vest (in dollars per share)	$ 19.30	$ 6.17
Weighted Average Exercise Price - Shares Exercisable (in dollars per share)	$ 8.94	$ 3.65
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Term - Shares Outstanding	8 years 2 months 16 days	7 years 2 months 1 day
Weighted Average Remaining Contractual Term - Shares Outstanding	8 years 2 months 16 days	7 years 2 months 1 day
Weighted Average Remaining Contractual Term - Shares Vested and expected to vest	8 years 2 months 16 days	7 years 2 months 1 day
Weighted Average Remaining Contractual Term - Shares Exercisable	8 years 2 months 16 days	7 years 2 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Aggregate Intrinsic Value - Outstanding	$ 27,413
Aggregate Intrinsic Value - Outstanding	26,484	27,413
Aggregate Intrinsic Value - Options Vested and expected to vest	25,502	26,716
Aggregate Intrinsic Value - Options Exercisable	18,898	24,306
Weighted-average grant date fair value per share of options granted during the period (in dollars per share)	$ 15.16	$ 7.08
Aggregate intrinsic value of options exercised during the period	$ 17,465	$ 307