Stock Based Awards - Summary of Stock Options Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shares Available for Grant
Shares Available for Grant, Beginning balance	1,350,543	991,401	9,533
Shares Available for Grant, Additional shares authorized	1,323,911	1,091,045	2,531,915
Shares Available for Grant, Options granted	(1,399,522)	(664,100)	(1,471,142)
Shares Available for Grant, Restricted stock units granted	(332,964)	(123,450)	(185,514)
Shares Available for Grant, Options cancelled	102,145	55,647	106,609
Shares Available for Grant, Ending balance	1,044,113	1,350,543	991,401
Number of shares
Number of Shares, Beginning balance	3,240,969	2,723,367	1,403,656
Number of Shares, Options granted	1,399,522	664,100	1,471,142
Number of Shares, Options exercised	(85,646)	(90,851)	(44,822)
Number of Shares, Options cancelled	(102,145)	(55,647)	(106,609)
Number of Shares, Ending balance	4,452,700	3,240,969	2,723,367
Number of Shares, Vested and expected to vest	4,323,511
Number of Shares, Exercisable	2,246,742
Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning balance	$ 11.51	$ 10.33	$ 1.90
Weighted Average Exercise Price, Options granted	10.04	15.34	18.68
Weighted Average Exercise Price, Options exercised	1.64	1.34	1.32
Weighted Average Exercise Price, Options cancelled	14.90	15.68	18.43
Weighted Average Exercise Price, Ending balance	11.16	$ 11.51	$ 10.33
Weighted Average Exercise Price, Vested and expected to vest	11.14
Weighted Average Exercise Price, Exercisable	$ 10.11
Weighted Average Remaining Contractual Life (in years)
Weighted Average Remaining Contractual Life, Options outstanding	7 years 9 months 18 days
Weighted Average Remaining Contractual Life, Vested and expected to vest	7 years 9 months 18 days
Weighted Average Remaining Contractual Life, Exercisable	7 years 2 months 12 days
Aggregate Intrinsic Value, Options outstanding	$ 25,162
Aggregate Intrinsic Value, Vested and expected to vest	24,632
Aggregate Intrinsic Value, Exercisable	$ 15,498