Convertible and Redeemable Convertible Preferred Stock - Change in Redemption Value of Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		7 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Jul. 21, 2015	Sep. 30, 2015	Sep. 30, 2014
Temporary Equity [Line Items]
Adjustment to redemption value	$ 222,130	$ 5,591		$ 374,015	$ 44,866
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