CAPITALIZED FEES PAID - Schedule of Capitalized Fees Paid (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Capitalized Fees paid
Gross carrying value	$ 220,000	$ 220,000
Accumulated amortization	(136,216)	(122,393)
Net carrying value	$ 83,784	97,607
Weighted average remaining amortization period	6 years 2 months 12 days
Capitalized Fees paid, Future amortization
Estimated amortization for the year 2024	$ 13,800
Estimated amortization for the year 2025	13,800
Estimated amortization for the year 2026	13,800
Estimated amortization for the year 2027	13,800
Estimated amortization for the year 2028	13,700
Estimated amortization after 2028	14,800
Royalty revenue
Capitalized Fees paid
Amortization expense	13,800	13,800	$ 13,800
United States
Capitalized Fees paid
Gross carrying value	120,000	120,000
Europe
Capitalized Fees paid
Gross carrying value	60,000	60,000
Japan
Capitalized Fees paid
Gross carrying value	40,000	40,000
GSK | Royalty revenue
Capitalized Fees paid
Amortization expense	$ 13,823	$ 13,823	$ 13,823