Intangible Assets (Textual 2 - HETLIOZ) - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2013	Feb. 29, 2004	Mar. 31, 2015	Mar. 31, 2014	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2006
Finite-Lived Intangible Assets [Line Items]
Milestone obligation under license agreement					$ 25,000		$ 25,000
HETLIOZ
Finite-Lived Intangible Assets [Line Items]
Acquisition of intangible assets	$ 3,000	$ 500		$ 8,000				$ 1,000
Intangible assets, estimated useful life				2022-12	2033-01	2033-01	2033-01
Cumulative worldwide sales milestone			$ 250,000		$ 250,000	$ 250,000
Intangible assets capitalized			25,000		25,000	25,000
Milestone obligation under license agreement			$ 25,000		$ 25,000	$ 25,000