Net Sales by Product - Summary of Net Sales by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Sales Information [Line Items]
Net product sales	$ 29,677	$ 12,175	$ 49,446	$ 23,456
BELBUCA [Member]
Sales Information [Line Items]
Net product sales	24,060	9,746	42,764	17,770
BUNAVAIL [Member]
Sales Information [Line Items]
Net product sales	821	1,020	1,876	2,834
Symproic [Member]
Sales Information [Line Items]
Net product sales	3,175	0	3,175	0
Product Sales [Member]
Sales Information [Line Items]
Net product sales	$ 28,056	$ 10,766	$ 47,815	$ 20,604