Net Sales by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Sales Information [Line Items]
Net product sales	$ 36,582	$ 29,677	$ 74,861	$ 49,446
BELBUCA
Sales Information [Line Items]
Net product sales	$ 32,344	$ 24,060	$ 65,813	$ 42,763
BELBUCA | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	89.00%	86.00%	89.00%	89.00%
Symproic
Sales Information [Line Items]
Net product sales	$ 3,413	$ 3,175	$ 7,593	$ 3,175
Symproic | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	9.00%	11.00%	10.00%	7.00%
BUNAVAIL
Sales Information [Line Items]
Net product sales	$ 688	$ 821	$ 755	$ 1,877
BUNAVAIL | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	2.00%	3.00%	1.00%	4.00%
Product sales, net
Sales Information [Line Items]
Net product sales	$ 36,445	$ 28,056	$ 74,161	$ 47,815