Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, Number of shares, beginning balance	623,936
Granted, Number of shares	2,610,174
Exercised, Number of share	(23,822)	0	0
Forfeited or expired, Number of share	(72,759)
Outstanding, Number of shares, ending balance	3,137,529	623,936
Outstanding as of December 31, 2015	3,137,529
Exercisable, Number of shares	276,909
Outstanding, Weighted Average Exercise Price, beginning balance	$ 13.69
Granted, Weighted Average Exercise Price	28.95
Exercised, Weighted Average Exercise Price	18.44
Forfeited or expired, Weighted Average Exercise price	37.11
Outstanding, Weighted Average Exercise Price, ending balance	25.81	$ 13.69
Stock options vested and expected to vest, Weighted Average Exercise Price	25.81
Exercisable, Weighted Average Exercise Price	$ 17.75
Outstanding, Weighted Average Remaining Contractual Term	6 years 5 months 1 day
Stock options vested and expected to vest, Weighted Average Remaining Contractual Term	6 years 5 months 1 day
Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months
Aggregate intrinsic value	$ 12,978
Vested and expected to vest, Aggregate Intrinsic Value	12,978
Exercisable, Aggregate Intrinsic Value	$ 2,470