Other License Agreements and Acquired Product Rights - Additional Information (Detail) $ in Thousands			1 Months Ended				3 Months Ended	12 Months Ended
	Dec. 07, 2016	Oct. 07, 2010 USD ($)	Mar. 31, 2018 CAD ($)	Oct. 31, 2017 CAD ($)	Aug. 31, 2017 CAD ($)	Aug. 31, 2015 USD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 12, 2017 CAD ($)
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	$ 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
Collaborative Arrangement, Product [Member] | Subsequent Event [Member] | Purdue Pharma [Member] | BELBUCA [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Milestone based payments received			$ 1,000,000
Distribution Agreement [Member] | BELBUCA [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Initial Term	3 years
Renewal term option for one year	2 years
Renewal term option for two years	1 year
Kunwha License Agreement [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Expiration date of the agreement						Aug. 31, 2015		Jul. 23, 2027
Upfront payment								$ 300
Up-front payment net of tax								250
Milestone payment received						$ 300
Kunwha License Agreement [Member] | Maximum [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Milestone payments								1,300
Milestone payments net of tax								1,100
TTY License and Supply Agreement [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Upfront payment		$ 300
Milestone payment received							$ 300	$ 1,200	$ 900	$ 0
Term of the agreement								15 years
TTY License and Supply Agreement [Member] | Maximum [Member]
Other License Agreements And Acquired Product Rights [Line Items]
Milestone payments		$ 1,300