Net Sales by Product (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Sales Information [Line Items]
Net product sales	$ 41,020	$ 38,278
BELBUCA
Sales Information [Line Items]
Net product sales	$ 36,402	$ 33,469
BELBUCA \| Revenue Benchmark \| Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	89.00%	89.00%
Symproic
Sales Information [Line Items]
Net product sales	$ 4,402	$ 4,179
Symproic \| Revenue Benchmark \| Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	11.00%	11.00%
BUNAVAIL
Sales Information [Line Items]
Net product sales	$ 0	$ 67
BUNAVAIL \| Revenue Benchmark \| Product Concentration Risk
Sales Information [Line Items]
Percent of net product sales	0.00%	0.00%
Product sales, net
Sales Information [Line Items]
Net product sales	$ 40,804	$ 37,715

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details