DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PPE and Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted cash		$ 5,029	$ 5,003	$ 5,029	$ 5,021	$ 5,006
Inventory reserve charge		4,600
Goodwill, Impairment Loss			0	0	0
Impairment of Intangible Assets, Finite-lived			446	75	0
Allocated Share-based Compensation Expense			12,800	9,100	6,700
Deferred Tax Assets, Valuation Allowance		432	263	432
Operating loss carryforwards			10,500
Impairment loss related to property and equipment recognized			0	0	0
Assets Held-for-sale, Not Part of Disposal Group		0	$ 0	0
Minimum | Intangible Asset Impairments [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			7 years
Maximum | Intangible Asset Impairments [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			10 years
ANI Canada [Member]
Deferred Tax Assets, Valuation Allowance		$ 300	$ 300	300	1,900
Operating loss carryforwards			6,500
Arthur Przybyl [Member]
Allocated Share-based Compensation Expense	$ 3,400		3,400
Employee Stock Purchase Plan 2016 [Member]
Allocated Share-based Compensation Expense			$ 180	$ 147	$ 102
Building and Building Improvements [Member] | Minimum
Property, Plant and Equipment, Useful Life			20 years
Building and Building Improvements [Member] | Maximum
Property, Plant and Equipment, Useful Life			40 years
Machinery, furniture and equipment [Member] | Minimum
Property, Plant and Equipment, Useful Life			1 year
Machinery, furniture and equipment [Member] | Maximum
Property, Plant and Equipment, Useful Life			10 years