Income Taxes - Schedule of (Benefit) Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ (58)	$ (91)	$ 265
State	3,242	1,689	2,386
International	16	(49)	218
Current provision (benefit) for income taxes	3,200	1,549	2,869
Deferred
Federal	(71,742)	0	0
State	(15,220)	0	0
International	16	(17)	99
Deferred provision (benefit) for income taxes	(86,946)	(17)	99
Income tax (benefit) provision	$ (83,746)	$ 1,532	$ 2,968