DEBT FINANCING - Narrative (Details) - USD ($) $ in Millions		1 Months Ended		9 Months Ended
	Aug. 28, 2020	Feb. 28, 2021	Jan. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Oct. 31, 2018
Line of Credit Facility [Line Items]
Interest expense				$ 0.3	$ 0.4
2018 Facility | LIBOR | Secured Debt
Line of Credit Facility [Line Items]
Basis spread on interest rate			8.50%
Amended 2018 Facility | Secured Debt
Line of Credit Facility [Line Items]
Increase in final payment fee percent	5.35%
Final payment fee percent	6.35%
Amended 2018 Facility | Line of Credit
Line of Credit Facility [Line Items]
Terminal fee							$ 1.7
Terminal fee, at carrying value				$ 1.0		$ 0.9
Amended 2018 Facility | LIBOR | Secured Debt
Line of Credit Facility [Line Items]
Basis spread on interest rate floor				0.20%
Interest rate during period				8.70%
Forecast | Amended 2018 Facility | Line of Credit
Line of Credit Facility [Line Items]
Monthly principal payments		$ 1.1
Term		24 months