REVENUE - Commercialization Agreement with Collegium (Details)				1 Months Ended		3 Months Ended	12 Months Ended	36 Months Ended	48 Months Ended
	Jan. 01, 2022 USD ($)	Jan. 01, 2019	Nov. 08, 2018 USD ($) $ / shares shares	Nov. 30, 2018 USD ($)	Jan. 31, 2018 USD ($) performance_obligation	Mar. 31, 2018 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Commercialization agreement, net | NUCYNTA products | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of performance obligations (performance obligation) | performance_obligation					3
Transaction price					$ 553,200,000
Total minimum royalties					537,000,000
Upfront payment					10,000,000	$ 10,000,000
Proceeds from transfer of inventory					6,200,000
Termination fee Collegium could pay					25,000,000
Commercialization agreement, net | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Period for annual payments to be made	60 days
Performance Obligation Transfer Of Finished Goods | NUCYNTA products | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price					55,700,000
Performance Obligation Commercialize And Facilitation Services | NUCYNTA products | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price					$ 497,500,000
Amended Commercialization Agreement | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price				$ 157,000,000
Total minimum royalties				132,000,000
Upfront payment				10,000,000
Proceeds from transfer of inventory				6,200,000
Commercialization agreement, reimbursement of royalties term		4 years
Commercialization agreement, warrant to purchase shares (in shares) | shares			1,041,667
Commercialization agreement, exercise price (in dollars per share) | $ / shares			$ 19.20
Commercialization agreement, warrant exercise period			4 years
Commercialization agreement, value of warrant			$ 8,800,000
Commercialization agreement, warrant value in transaction price				$ 8,800,000
Agreement termination period				60 days
Amended Commercialization Agreement | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreement termination period	12 months						12 months
Commercialization Agreement, 58% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales	58.00%						58.00%	58.00%	58.00%
Net revenue threshold	$ 233,000,000.0
Commercialization Agreement, 25% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales	25.00%
Commercialization Agreement, 17.5% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales	17.50%
Net revenue threshold	$ 258,000,000.0
Commercialization Agreement, 14% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales							14.00%	14.00%	14.00%
Commercialization Agreement, 65% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales							65.00%	65.00%	65.00%
Net revenue threshold								$ 180,000,000.0
Commercialization Agreement, 20% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales							20.00%	20.00%	20.00%
Commercialization Agreement, 15% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales							15.00%	15.00%	15.00%
Net revenue threshold								$ 258,000,000.0
Minimum | Forecast | NUCYNTA products | Third Party
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total revenues									$ 180,000,000.0
Minimum | Commercialization Agreement, 58% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								210,000,000.0
Minimum | Commercialization Agreement, 25% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold	$ 233,000,000.0
Minimum | Commercialization Agreement, 14% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								180,000,000.0
Minimum | Commercialization Agreement, 20% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								233,000,000.0
Maximum | Forecast | Third Party
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty obligation									$ 8,800,000
Maximum | Commercialization Agreement, 58% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								233,000,000.0
Period for quarterly payments to be made	45 days
Maximum | Commercialization Agreement, 25% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold	$ 258,000,000.0
Maximum | Commercialization Agreement, 14% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								210,000,000.0
Maximum | Commercialization Agreement, 20% Royalty on Net Annual Sales | Forecast | Collegium Pharmaceutical Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Net revenue threshold								$ 258,000,000.0
Collegium Pharmaceutical Inc | Amended Commercialization Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Termination fee Collegium could pay				$ 5,000,000
Collegium Pharmaceutical Inc | Amended Commercialization Agreement | Forecast | Product
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercialization agreement, termination, net sales threshold	$ 170,000,000.0						$ 180,000,000.0
Collegium Pharmaceutical Inc | Commercialization Agreement, 14% Royalty on Net Annual Sales | Forecast | Third Party
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on annual net sales							14.00%	14.00%	14.00%
Collegium Pharmaceutical Inc | Minimum | Forecast | NUCYNTA products | Third Party
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty obligation									$ 34,000,000.0