SEGMENT REPORTING - Revenue (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 segment
Segment reporting
Number of segments | segment	2		1
Revenue recognition	$ 64,477	$ 54,521
Depreciation and amortization	14,557	10,898
Selling, general, and administrative	28,817	17,587
Operating (Loss)/Income	(19,195)	3,045
Interest expense, net	(6,613)	(2,454)
Other expense, net	(89)	(515)
(Loss)/Income Before Benefit for Income Taxes	(25,897)	76
Operating segments | Generics, Established Brands and Other
Segment reporting
Revenue recognition	63,185	54,521
EBITDA	14,531	21,839
Operating segments | Rare Disease
Segment reporting
Revenue recognition	1,292
EBITDA	(10,448)	(1,278)
Unallocated expenses
Segment reporting
Depreciation and amortization	(14,557)	(10,898)
Selling, general, and administrative	(8,721)	(6,618)
Operating (Loss)/Income	(19,195)	3,045
Interest expense, net	(6,613)	(2,454)
Other expense, net	$ (89)	$ (515)