FAIR VALUE OF FINANCIAL INSTRUMENTS - Schedule of Fair Value of Financial Liabilities (Details) - Fair Value Measurement on a Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	$ 3,965	$ 6,795
Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	3,965	6,795
2017 Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	2,957	5,030
2017 Placement Warrants | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
2017 Placement Warrants | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
2017 Placement Warrants | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	2,957	5,030
2016 Placement Warrants
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	1,008	1,765
2016 Placement Warrants | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
2016 Placement Warrants | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	0	0
2016 Placement Warrants | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Warrant liabilities	$ 1,008	$ 1,765