Stock-based Compensation - Summary of Stock Option Activity (Detail) - 2014 and 2015 Equity Incentive Plan [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Shares Outstanding, Beginning Balance	3,684
Shares, Granted	1,796
Shares, Exercised	(163)
Shares, Cancelled or forfeited	(199)
Shares Outstanding, Ending Balance	5,118	3,684
Shares, Exercisable	2,147
Shares, Vested and expected to vest	5,118
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-average Exercise Price Outstanding, Beginning Balance	$ 5.52
Weighted-average Exercise Price, Granted	12.58
Weighted-average Exercise Price, Exercised	1.10
Weighted-average Exercise Price, Cancelled or forfeited	15.04
Weighted-average Exercise Price, Outstanding, Ending Balance	7.77	$ 5.52
Weighted-average Exercise Price, Exercisable	3.90
Weighted-average Exercise Price, Vested and expected to vest	$ 7.77
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average Remaining Contractual Life (Years) Outstanding	8 years 6 months	9 years 1 month 6 days
Weighted-average Remaining Contractual Life (Years), Exercisable	8 years
Weighted-average Remaining Contractual Life (Years), Vested and expected to vest	8 years 6 months
Aggregate Intrinsic Value Outstanding	$ 57,400	$ 44,472
Aggregate Intrinsic Value, Exercisable	32,198
Aggregate Intrinsic Value, Vested and expected to vest	$ 57,400