License and Development Agreements - Endo License and Development Agreement - Additional Information (Detail) $ in Millions	1 Months Ended				3 Months Ended
	Nov. 30, 2015 USD ($)	Oct. 31, 2015 USD ($)	Feb. 28, 2015 USD ($)	May 31, 2012 USD ($)	Mar. 31, 2017 USD ($) Clinical_Trials	Jun. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	Jan. 31, 2012 USD ($)
Revenue Recognition, Milestone Method [Line Items]
Non-refundable payment received								$ 30
Potential milestone payments on intellectual property rights				$ 15
Potential payments upon filing and acceptance			$ 10
Potential milestone payment receivable upon regulatory approval		$ 50
Milestone payment upon regulatory approval deferred for future revenue recognition	$ 20
Patent extension starting period					2020
Patent extension ending period					2027
Royalty payment description					$50 million upon regulatory approval, earned in October 2015 and received in November 2015. Of the $50 million received in November 2015, $20 million related to a patent extension and was recorded as deferred revenue because all or a portion of such $20 million was contingently refundable to Endo if a third party generic product was introduced in the U.S. during the patent extension period from 2020 to 2027. However, due to the Company and Endo entering into a Termination Agreement on December 7, 2016 which terminated the BELBUCA® license to Endo effective January 6, 2017, the deferred $20 million was recognized as revenue during the three months ended March 31, 2017 in the accompanying condensed consolidated statement of operations. (See note 7).
Endo Agreement [Member]
Revenue Recognition, Milestone Method [Line Items]
Deferred revenue refund payment					$ 20
Termination agreement date					Dec. 07, 2016
License termination effective date					Jan. 06, 2017
Clinical Trials Full Enrollment [Member]
Revenue Recognition, Milestone Method [Line Items]
Potential milestone payment received, clinical development					$ 20
Number of clinical trials | Clinical_Trials					2
Clinical Trials One [Member]
Revenue Recognition, Milestone Method [Line Items]
Potential milestone payment received, clinical development							$ 10
Clinical Trials Two [Member]
Revenue Recognition, Milestone Method [Line Items]
Potential milestone payment received, clinical development						$ 10