Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of shares under stock option, Beginning balance	4,246,525	3,561,304	3,202,335
Number of shares Granted	1,454,626	1,035,459	791,865
Number of shares Option assumed from acquisition		221,759
Number of shares Exercised	(650,185)	(385,238)	(201,200)
Number of shares forfeited/cancelled	(470,591)	(186,669)	(231,696)
Number of shares under stock option, Ending balance	4,580,375	4,246,525	3,561,304
Weighted average exercise price, Beginning balance	$ 5.99	$ 4.62	$ 3.77
Number of stock options, Vested and exercisable	2,854,734
Weighted average exercise price, Stock options granted	$ 13.43	11.13	7.74
Number of stock options, Vested or expected to vest	4,250,315
Weighted average exercise price, Option assumed from acquisition		1.65
Weighted average exercise price, Stock options exercised	$ 4.43	3.50	2.41
Weighted average exercise price, Stock options forfeited/cancelled	9.65	8.33	5.45
Weighted average exercise price, Ending balance	8.20	$ 5.99	$ 4.62
Weighted average exercise price, Vested and exercisable	5.60
Weighted average exercise price, Vested and expected to vest	$ 7.83
Weighted Average Remaining Contractual Life, Outstanding	7 years 2 months 12 days
Weighted Average Remaining Contractual Life, Vested and exercisable	6 years 3 months 18 days
Weighted Average Remaining Contractual Life, Vested and expected to vest	7 years 1 month 6 days
Stock options aggregate intrinsic value, Exercised	$ 6,409	$ 3,472	$ 1,069
Stock options aggregate intrinsic value, Outstanding	20,626
Stock options aggregate intrinsic value, Exercisable	19,131
Stock options aggregate intrinsic value, Vested and expected to vest	$ 20,454