Share-Based Compensation - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Options, Granted	596,995
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Options, Outstanding, Beginning balance	3,168,067
Number of Options, Granted	596,995
Number of Options, Exercised	(31,168)
Number of Options, Forfeited	(2,200)
Number of Options, Outstanding, Ending balance	3,731,694
Exercisable at June 30, 2015	607,118
Weighted-average Exercise Price, Outstanding, Beginning balance | $ / shares	$ 12.61
Weighted-average Exercise Price, Granted | $ / shares	23.36
Weighted average Exercise Price, Exercised | $ / shares	10.53
Weighted-average Exercise Price, Forfeited | $ / shares	17.65
Weighted-average Exercise Price, Outstanding, Ending balance | $ / shares	14.34
Weighted-average Exercise Price, Exercisable | $ / shares	$ 8.97
Weighted-average Remaining Contractual Term in Years, Outstanding	7 years 11 days
Weighted-average Remaining Contractual Term in Years, Exercisable	4 years 6 months 4 days
Aggregate Intrinsic Value, Exercised | $	$ 455
Aggregate Intrinsic Value, Outstanding | $	42,392
Aggregate Intrinsic Value, Exercisable | $	$ 10,165