Stock-Based Compensation - Stock Option Activity and Related Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares outstanding, beginning balance	3,294,822
Shares, granted	1,455,150
Shares, cancelled	(45,939)
Shares, forfeited	(335,449)
Shares, exercised	(201,622)
Shares outstanding, ending balance	4,166,962	3,294,822
Shares, options vested and expected to vest	4,117,768
Shares, options exercisable	2,108,076
Outstanding weighted-average exercise price per share, beginning balance	$ 9.98
Weighted-average exercise price per share, granted	12.94
Weighted-average exercise price per share, cancelled	14.97
Weighted-average exercise price per share, forfeited	14.00
Weighted-average exercise price per share, exercised	3.58
Weighted-average exercise price per share, ending balance	10.94	$ 9.98
Options vested and expected to vest	10.93
Options exercisable	$ 8.37
Outstanding weighted-average remaining contractual life	7 years 9 months 22 days	8 years 29 days
Weighted-average remaining contractual term, options vested and expected to vest	7 years 9 months 18 days
Weighted-average remaining contractual term, options exercisable	6 years 11 months 9 days
Outstanding aggregate intrinsic value, ending balance	$ 19,163	$ 17,985
Aggregate intrinsic value, options vested and expected to vest	19,074
Aggregate intrinsic value, options exercisable	$ 15,006