ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Organization (Details) $ in Millions	1 Months Ended	6 Months Ended	12 Months Ended
	Jan. 31, 2018 USD ($)	Jun. 30, 2018 product	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Organization
Number of products | product		3
Commercialization agreement | Collegium
Organization
Termination fee the Company could pay	$ 80.0
Period of notice (in months)	12 months
Termination fee Collegium could pay	$ 25.0
Number of products marketed by Collegium | product		2
Commercialization agreement | NUCYNTA products | Collegium
Organization
Termination fee Collegium could pay	$ 25.0
Commercialization agreement | NUCYNTA products | Collegium | Forecast
Organization
Minimum annual royalties			$ 135.0	$ 135.0	$ 135.0	$ 132.0