Changes to Accrued Cease-Use Liability (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Beginning balance		$ 972	$ 2,326	$ 1,983	$ 2,678
Change in estimate	[1]	0	0	(830)	(87)
Payments		(58)	(175)	(239)	(440)
Ending balance		$ 914	$ 2,151	$ 914	$ 2,151

[1] Change in estimate was offset by an increase in deferred rent of approximately $246,000 during the first quarter of 2016.