Segment Reporting - Summary of Net Sales by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Sales Information [Line Items]
Net product sales	$ 8,118	$ 2,009	$ 23,798	$ 6,221
BELBUCA [Member]
Sales Information [Line Items]
Net product sales	6,437		17,554		$ 0
BUNAVAIL [Member]
Sales Information [Line Items]
Net product sales	$ 1,681	$ 2,009	$ 6,244	$ 6,221