Common Stock and Preferred Stock - Additional Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Vote / shares $ / shares shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares	Dec. 31, 2012 shares	Jun. 30, 2013 shares
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			8,631,427	8,631,427
Each share of common stock is entitled to vote | Vote / shares	1
Preferred stock, shares authorized	15,000,000	15,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0				0
Accretion of mandatorily redeemable convertible preferred stock | $	$ 0	$ 0	$ 4,653
Preferred Stock, redemption rate	8.00%
Preferred stock warrants were converted into warrants to purchase common stock	572,246
Exercise price of common stock warrants | $ / shares	$ 8.77
Minimum [Member]
Common And Preferred Stock [Line Items]
Warrant expiration date	2018
Maximum [Member]
Common And Preferred Stock [Line Items]
Warrant expiration date	2023
Mandatorily Redeemable Convertible Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Redemption terms	At any time after November 29, 2017 and upon 30 day notice from the holders of 65% of the outstanding Preferred Stock
Preferred stock, redemption date	Nov. 29, 2017
Preferred stock, redemption notice period	30 days
Holders outstanding preferred stock	65.00%
Series A Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			(557,339)
Preferred stock converted into common stock on a basis				1.403030-for-one basis
Series B Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			(515,836)
Preferred stock converted into common stock on a basis				1.559429-for-one basis
Series C Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			(3,551,060)
Preferred stock converted into common stock on a basis				One-for-one basis
Series D Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			(2,430,054)
Preferred stock converted into common stock on a basis				One-for-one basis
Series E Preferred Stock [Member]
Common And Preferred Stock [Line Items]
Conversion of Convertible Preferred Stock Into Common Stock, Shares			(1,063,951)
Preferred stock converted into common stock on a basis				One-for-one basis