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	Dec. 31, 2012
2009 Non-Employee Director Grants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option Outstanding Beginning Balance	3,200	3,200	3,200
Options Granted, Options Outstanding	0	0	0
Options Canceled, Options Outstanding	0	0	0
Options Exercised, Options Outstanding	0	0	0
Option Outstanding Ending Balance	3,200	3,200	3,200
Weighted Average Exercise Price, Beginning Balance	$ 1.12	$ 1.12	$ 1.12
Weighted Average Exercise Price, Ending Balance	$ 1.12	$ 1.12	$ 1.12
2009 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option Outstanding Beginning Balance	2,231,800	1,044,100	416,400
Options Granted, Options Outstanding	1,378,600	1,577,000	650,200
Options Canceled, Options Outstanding	(376,072)	(325,300)	(15,200)
Options Exercised, Options Outstanding	(276,712)	(64,000)	(7,300)
Option Outstanding Ending Balance	2,957,616	2,231,800	1,044,100
Weighted Average Exercise Price, Beginning Balance	$ 6.34	$ 6.52	$ 3.75
Options Granted, Weighted Average Exercise Price	12.03	3.38	8.19
Options Canceled, Weighted Average Exercise Price	6.84	11.38	3.92
Options Exercised, Weighted Average Exercise Price	6.14	4.76	2.35
Weighted Average Exercise Price, Ending Balance	$ 8.95	$ 6.34	$ 6.52
Aggregate Intrinsic Value, Beginning Balance	$ 4,506	$ 8,323	$ 1,860	$ 55