INTANGIBLE ASSETS - Components (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
INTANGIBLE ASSETS
Gross Carrying Amount	$ 355,170	$ 307,225
Accumulated Amortization	$ (166,659)	(126,837)
Weighted Average Amortization Period	9 years 4 months 24 days
Amortization of intangible assets	$ 39,900	40,200	$ 31,700
Intangible asset impairment charge	446	75	$ 0
Acquired ANDA intangible assets
INTANGIBLE ASSETS
Gross Carrying Amount	106,415	64,704
Accumulated Amortization	$ (42,367)	(30,169)
Weighted Average Amortization Period	8 years 9 months 18 days
NDAs and product rights
INTANGIBLE ASSETS
Gross Carrying Amount	$ 230,974	230,974
Accumulated Amortization	$ (112,483)	(87,352)
Weighted Average Amortization Period	10 years
Marketing and distribution rights
INTANGIBLE ASSETS
Gross Carrying Amount	$ 17,157	10,923
Accumulated Amortization	$ (11,386)	(8,982)
Weighted Average Amortization Period	5 years 8 months 12 days
Intangible asset impairment charge	$ 400
Non-compete agreement
INTANGIBLE ASSETS
Gross Carrying Amount	624	624
Accumulated Amortization	$ (423)	$ (334)
Weighted Average Amortization Period	7 years

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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