DEBT (Details) $ in Thousands						3 Months Ended			6 Months Ended
	Jun. 29, 2023	Jul. 15, 2022 USD ($)	Dec. 10, 2020 USD ($)	Nov. 25, 2019 USD ($)	Nov. 11, 2019 USD ($) tranche	Jun. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Line of Credit Facility [Line Items]
Embedded debt derivative						$ 760			$ 760		$ 760
Collateral Agent, Pharmakon
Line of Credit Facility [Line Items]
Embedded debt derivative						800			800		$ 800
Term Loan | Collateral Agent, Pharmakon | Tranche A and B
Line of Credit Facility [Line Items]
Payment for debt prepayment premium, including accrued and unpaid interest		$ 500
Debt extinguishment loss							$ 900
Term Loan | Collateral Agent, Pharmakon | Tranche A
Line of Credit Facility [Line Items]
Payment for debt prepayment		5,000
Term Loan | Collateral Agent, Pharmakon | Tranche B
Line of Credit Facility [Line Items]
Payment for debt prepayment		$ 20,000
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity					$ 100,000
Term loan, principal payment						8,000			24,000
Term loan, maturity term, potential reduction (up to)					1 year
Term loan, amortization period, potential reduction (up to)					1 year
Prepayment premium percentage on principal if prepaid prior to fourth anniversary and after third anniversary of funding					1.00%
Prepayment premium percentage on principal if prepaid after fourth anniversary of funding					0.50%
Minimum net sales threshold, trailing period					12 months
Minimum net sales threshold					$ 85,000
Interest expense						1,600		$ 2,700	3,300	$ 5,400
Unamortized discount and issuance costs						$ 500			$ 500
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | Debt Instrument, Quarterly Periodic Payment, Period One
Line of Credit Facility [Line Items]
Term loan, first quarterly principal payment due in					33 months
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | Three-month LIBOR
Line of Credit Facility [Line Items]
Basis spread on floating interest rate					7.50%
Interest rate						10.85%			10.85%
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, floor rate					2.00%
Debt instrument, cap rate					3.35%
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Debt instrument, cap rate	3.35%
Interest rate						10.85%			10.85%
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | Tranche A
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity					$ 80,000
Line of credit, maximum borrowing capacity, number of available tranches | tranche					2
Proceeds from line of credit, net				$ 77,300
Biopharma Credit Investments V (Master) LP | Keryx | Term Loan | Collateral Agent, Pharmakon | Tranche B
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity					$ 20,000
Proceeds from line of credit, net			$ 20,000