Stockholders' Equity - Summary of Stock Option Activity Under the 2010 Stock Plan and the 2013 Stock Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding, beginning balance			1,267,329
Number of Shares, Granted	0	0	0
Number of Shares, Exercised			(366,044)
Number of Shares, Cancelled			(51,332)
Number of Shares, Outstanding, ending balance	849,953		849,953	1,267,329
Number of Shares, Exercisable as of June 30, 2017	746,590		746,590
Weighted-Average Exercise Price, Outstanding, beginning balance			$ 16.22
Weighted-Average Exercise Price, Exercised			11.28
Weighted-Average Exercise Price, Cancelled			24.39
Weighted- Average Exercise Price, Outstanding, ending balance	$ 17.86		17.86	$ 16.22
Weighted-Average Exercise Price, Exercisable as of June 30, 2017	$ 16.43		$ 16.43
Weighted-Average Remaining Contractual Term, Outstanding			5 years 10 months 24 days	6 years 7 months 6 days
Weighted-Average Remaining Contractual Term, Exercisable as of June 30, 2017			5 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 19,500		$ 19,500	$ 8,355
Aggregate Intrinsic Value, Exercisable as of June 30, 2017	$ 18,061		$ 18,061