Net Sales by Product (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Sales Information [Line Items]
Net product sales	$ 39,443	$ 30,306	$ 114,304	$ 79,752
BELBUCA
Sales Information [Line Items]
Net product sales	$ 34,758	$ 26,514	$ 100,572	$ 69,277
BELBUCA | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	90.00%	90.00%	89.00%	89.00%
Symproic
Sales Information [Line Items]
Net product sales	$ 3,453	$ 2,172	$ 11,046	$ 5,348
Symproic | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	9.00%	7.00%	10.00%	7.00%
BUNAVAIL
Sales Information [Line Items]
Net product sales	$ 574	$ 937	$ 1,328	$ 2,813
BUNAVAIL | Revenue Benchmark | Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	1.00%	3.00%	1.00%	4.00%
Product sales, net
Sales Information [Line Items]
Net product sales	$ 38,785	$ 29,623	$ 112,946	$ 77,438