SEGMENT REPORTING - Revenue (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) segment productFamily brand	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment reporting
Number of operating segments | segment	2
Established brand products | brand	16
Product families | productFamily	100
Net Revenues	$ 614,376,000	$ 486,816,000	$ 316,385,000
Cost of sales (excluding depreciation and amortization)	(250,210,000)	(181,513,000)	(138,785,000)
Research and Development	(44,581,000)	(34,286,000)	(22,318,000)
Selling, general, and administrative	(249,636,000)	(161,697,000)	(124,044,000)
Depreciation and amortization	(67,731,000)	(59,791,000)	(56,972,000)
Fair value adjustment	619,000	(1,426,000)	(3,758,000)
Restructuring activities	0	(1,132,000)	(5,679,000)
Gain on sale of building	5,347,000	0	0
Intangible asset impairment charge	(7,600,000)	0	(112,000)
Operating Income (Loss)	584,000	46,971,000	(35,283,000)
Unrealized gain on investment in equity securities	6,307,000	0	0
Interest expense, net	(17,602,000)	(26,940,000)	(28,052,000)
Other (expense) income, net	(4,033,000)	(159,000)	670,000
Loss on extinguishment of debt	7,468,000	0	0
(Loss) Income Before (Benefit) Expense for Income Taxes	(22,212,000)	19,872,000	(62,665,000)
Operating Segments | Generics and Other
Segment reporting
Net Revenues	320,034,000	289,314,000	235,237,000
Cost of sales (excluding depreciation and amortization)	(168,371,000)	(152,739,000)	(125,835,000)
Research and Development	(30,519,000)	(28,197,000)	(19,964,000)
Selling, general, and administrative	(5,120,000)	(2,451,000)	(3,963,000)
Depreciation and amortization	0	0	0
Fair value adjustment	0	0	0
Restructuring activities		0	0
Gain on sale of building	0
Intangible asset impairment charge	0		0
Operating Income (Loss)	116,024,000	105,927,000	85,475,000
Unrealized gain on investment in equity securities	0
Interest expense, net	0	0	0
Other (expense) income, net	0	0	0
Loss on extinguishment of debt	0
(Loss) Income Before (Benefit) Expense for Income Taxes	116,024,000	105,927,000	85,475,000
Operating Segments | Rare Disease and Brands
Segment reporting
Net Revenues	294,342,000	197,502,000	81,148,000
Cost of sales (excluding depreciation and amortization)	(81,839,000)	(28,774,000)	(12,950,000)
Research and Development	(14,062,000)	(6,089,000)	(2,354,000)
Selling, general, and administrative	(125,972,000)	(73,466,000)	(55,306,000)
Depreciation and amortization	0	0	0
Fair value adjustment	0	0	0
Restructuring activities		0	0
Gain on sale of building	0
Intangible asset impairment charge	0		0
Operating Income (Loss)	72,469,000	89,173,000	10,538,000
Unrealized gain on investment in equity securities	0
Interest expense, net	0	0	0
Other (expense) income, net	0	0	0
Loss on extinguishment of debt	0
(Loss) Income Before (Benefit) Expense for Income Taxes	72,469,000	89,173,000	10,538,000
Corporate and Unallocated
Segment reporting
Net Revenues	0	0	0
Cost of sales (excluding depreciation and amortization)	0	0	0
Research and Development	0	0	0
Selling, general, and administrative	(118,544,000)	(85,780,000)	(64,775,000)
Depreciation and amortization	(67,731,000)	(59,791,000)	(56,972,000)
Fair value adjustment	619,000	(1,426,000)	(3,758,000)
Restructuring activities		(1,132,000)	(5,679,000)
Gain on sale of building	5,347,000
Intangible asset impairment charge	(7,600,000)		(112,000)
Operating Income (Loss)	(187,909,000)	(148,129,000)	(131,296,000)
Unrealized gain on investment in equity securities	6,307,000
Interest expense, net	(17,602,000)	(26,940,000)	(28,052,000)
Other (expense) income, net	(4,033,000)	(159,000)	670,000
Loss on extinguishment of debt	7,468,000
(Loss) Income Before (Benefit) Expense for Income Taxes	$ (210,705,000)	$ (175,228,000)	$ (158,678,000)