DEBT - Carrying Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt instruments
Principal Loan Balance	$ 80,000	$ 75,000
Unamortized debt discount and issuance cost	(2,039)	(3,088)
Cumulative accretion of exit fee	530	331
Long-term debt, net	$ 78,491	72,243
Athyrium Credit Facility
Debt instruments
Unamortized debt discount and issuance cost		$ (3,088,000)

Face (par) amount of debt instrument at time of issuance.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant