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DEBT - Summary of Long-term Debt (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020	May 20, 2020	Sep. 09, 2014
Debt Instrument [Line Items]
Gross, long-term debt	$ 84,172,000	$ 84,118,000
Unamortized debt discounts	0	(16,000)
Carrying value	84,172,000	84,102,000
Less: current portion of long-term debt	(12,338,000)	(11,942,000)
Net, long-term debt	$ 71,834,000	72,160,000
Senior Notes \| 13% Senior Secured Note due 2024
Debt Instrument [Line Items]
Interest rate	13.00%		13.00%
Gross, long-term debt	$ 80,250,000	80,250,000
Less: current portion of long-term debt	(9,500,000)
Net, long-term debt	70,800,000
Senior Notes \| Royalty rights obligation
Debt Instrument [Line Items]
Gross, long-term debt	$ 3,587,000	3,533,000
Convertible notes \| 2.50% Convertible Notes due 2021
Debt Instrument [Line Items]
Interest rate	2.50%			2.50%
Gross, long-term debt	$ 335,000	335,000
Carrying value	$ 300,000	$ 300,000