Stock-Based Compensation - Schedule of Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares Under Option
Granted	1,010,457
Exercised	(4,766)	0	0
Forfeited	(3,365)
Outstanding balance at December 31, 2015	1,397,511
Exercisable at December 31, 2015	384,087
Vested and expected to vest at December 31, 2015	1,254,325
Weighted Average Exercise Price
Outstanding balance at January 1, 2015	$ 5.40
Granted	16.30
Exercised	5.85
Forfeited	5.85
Outstanding balance at December 31, 2015	13.28	$ 5.40
Exercisable at December 31, 2015	6.71
Vested and expected to vest at December 31, 2015	$ 13.00
Weighted Average Remaining Contractual Term (years)
Outstanding balance	8 years 6 months 29 days	7 years 2 months 27 days
Exercisable at December 31, 2015	6 years 6 months 18 days
Vested and expected to vest at December 31, 2015	8 years 5 months 27 days
Aggregate Intrinsic Value
Options outstanding, Aggregate intrinsic value	$ 9,204,403	$ 1,275,980
Options exercisable, Aggregate intrinsic value	5,057,062
Options vested and expected to vest, Aggregate intrinsic value	$ 8,614,743