Preferred Stock - Changes in Redemption Value of Convertible Preferred Stock (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Temporary Equity [Line Items]
Adjustment to redemption value	$ 374,015
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Adjustment to redemption value	46,976
Series B-1 Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Adjustment to redemption value	36,961
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Adjustment to redemption value	52,832
Series D Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Adjustment to redemption value	237,246
Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Adjustment to redemption value	$ (374,015)