FAIR VALUE MEASUREMENTS AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Reconciliation of liabilities measured using Level 3 (Details) - Fair Value, Inputs, Level 3 - Compound Derivative Liability - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value at beginning of period	$ 977	$ 161
Change in fair value	846	174
Fair value at end of period	$ 1,823	$ 335