Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Outstanding Options, Beginning Balance	1,514,471
Number of Outstanding Options, Granted	1,715,028
Number of Outstanding Options, Exercised	(197,253)
Number of Outstanding Options, Canceled	(406,966)
Number of Outstanding Options, Ending Balance	2,625,280	1,514,471
Number of Outstanding Options, Vested and Expected to Vest, Ending Balance	2,625,280
Number of Outstanding Options, Exercisable, Ending Balance	899,931
Weighted Average Price	$ 8.83	$ 4.60
Weighted Average Price, Granted	11.29
Weighted Average Price, Exercised	2.78
Weighted Average Price, Canceled	6.37
Weighted Average Price, Options Vested and Expected to Vest, Ending Balance	8.83
Weighted Average Price, Options Exercisable, Ending Balance	$ 4.91
Weighted Average Contractual Term, Outstanding	8 years 7 days
Weighted Average Contractual Term, Options Vested and Expected to Vest	8 years 7 days
Weighted Average Contractual Term, Options Exercisable	6 years 7 months 21 days
Aggregate Intrinsic Value, Outstanding	$ 6,684
Aggregate Intrinsic Value, Options Vested and Expected to Vest	6,684
Aggregate Intrinsic Value, Options Exercisable	$ 5,063