Other License Agreements and Acquired Product Rights - Additional Information (Detail) $ in Millions		1 Months Ended					3 Months Ended	12 Months Ended
	Oct. 07, 2010 USD ($)	Jan. 08, 2019	Dec. 31, 2018 CAD ($)	Mar. 31, 2018 CAD ($)	Oct. 31, 2017 CAD ($)	Aug. 31, 2017 CAD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jul. 12, 2017 CAD ($)
Subsequent Event [Member] | Purdue Pharma [Member] | BELBUCA [Member]
Other License Agreements And Acquired Product Rights [Line Items]
License agreement effective date		Mar. 11, 2019
Collaborative Arrangement, Product [Member] | Purdue Pharma [Member] | BELBUCA [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Upfront and potential milestones payable											$ 1,500,000
Milestone based payments received			$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 500,000
Collaborative Arrangement, Product [Member] | Purdue Pharma [Member] | BELBUCA [Member] | Maximum [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Upfront and potential milestones payable											$ 4,500,000
TTY License and Supply Agreement [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Upfront payment	$ 0.3
Term of the agreement								15 years
Milestone payment received							$ 0.3	$ 1.5	$ 1.2	$ 0.9
TTY License and Supply Agreement [Member] | Maximum [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Milestone payments	$ 1.3