INCOME TAXES - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Federal statutory income tax benefit	$ (15,824)	$ (8,888)	$ (19,911)
State and local taxes	509	(3,264)	(2,784)
Orphan Drug & General Business Credit	(29,363)	(44,114)	(43,124)
Stock compensation expense	7,859	(1,101)	239
Changes in the fair value of contingent consideration	0	0	(1,804)
Foreign Source Income Subject to U.S. Tax	16,878	6,266	(52)
Foreign tax rate differential	(16,971)	(16,238)	(30,639)
Section 162(m) limitation	6,304	9,571	8,294
Tax Reserves	15,530	2,166	12,123
Intra-entity transfer of assets	(3,920)	(852,338)	0
CARES Act carryback claim	0	(2,201)	0
Valuation allowance/deferred benefit	6,821	6,876	7,827
Other	907	1,843	(1,132)
Benefit from income taxes	(11,270)	(901,422)	(70,963)
Valuation allowance	109,176	$ 93,075
Dutch
Income Tax Contingency [Line Items]
Valuation allowance	$ 9,300		$ 29,600