Stock-Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended	12 Months Ended
	Jun. 13, 2012	Sep. 30, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares subject to options, Beginning Balance		4,166,214
Number of shares subject to options, Granted		1,041,400
Number of shares subject to options, Exercised	(573,941)	(769,070)
Number of shares subject to options, Forfeited		(409,631)
Number of shares subject to options, Expired		(283)
Number of shares subject to options, Ending Balance		4,028,630	4,166,214
Number of shares subject to options, Exercisable		1,236,482
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price per share, Beginning Balance		$ 12.70
Weighted average exercise price per share, Granted		27.10
Weighted average exercise price per share, Exercised		2.75
Weighted average exercise price per share, Forfeited		20.87
Weighted average exercise price per share, Expired		5.95
Weighted average exercise price per share, Ending Balance		17.50	$ 12.70
Weighted average exercise price per share, Exercisable		$ 3.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term, Beginning Balance		7 years 8 months 9 days	7 years 6 months 22 days
Weighted average remaining contractual term, Ending Balance		7 years 8 months 9 days	7 years 6 months 22 days
Weighted average remaining contractual term, Exercisable		5 years 3 months 22 days
Aggregate intrinsic value, Beginning Balance		$ 63,186
Aggregate intrinsic value, Ending Balance		65,121	$ 63,186
Aggregate intrinsic value, Exercisable		$ 37,859