Nature of Business and Summary of Significant Accounting Policies - Intangible Assets with Finite Useful Lives, Amortized Over Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2018
Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	15 years
BELBUCA License and Distribution Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	10 years
U.S. Product Rights [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	8 years
U.S. Product Rights [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	12 years
Eu Product Rights [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	7 years
Eu Product Rights [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	11 years