Stock-Based Compensation (Summary of Option Activity) (Details) - Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Thousands	Total
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning Balance, Outstanding, Number of Options	10,371,472
Granted, Number of Options	310,043
Exercised, Number of Options	(476,231)
Forfeited, Number of Options	(278,638)
Expired, Number of Options	(14,824)
Ending Balance, Outstanding, Number of Options	9,911,822
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning Balance, Outstanding, Weighted-Average Exercise Price	$ 4.59
Granted, Weighted-Average Exercise Price	18.73
Exercised, Weighted-Average Exercise Price	1.18
Forfeited, Weighted-Average Exercise Price	5.90
Expired, Weighted-Average Exercise Price	0.97
Ending Balance, Outstanding, Weighted-Average Exercise Price	$ 5.16
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted-Average Remaining Contractual Term	8 years 15 days
Outstanding, Aggregate Intrinsic Value	$ 67,820
Exercisable, Number of Options	3,769,311
Exercisable, Weighted-Average Exercise Price	$ 1.16
Exercisable, Weighted-Average Remaining Contractual Term	7 years 1 month 6 days
Exercisable, Aggregate Intrinsic Value	$ 39,645
Vested or expected to vest, Number of Options	9,431,273
Vested or expected to vest, Weighted-Average Exercise Price	$ 4.95
Vested or expected to vest, Weighted-Average Remaining Contractual Term	8 years 18 days
Vested or expected to vest, Aggregate Intrinsic Value	$ 65,494