FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Money market funds	$ 24,157
Total	24,157
Liabilities:
Derivative liabilities	16	$ 4,023
Total	16	4,023
Level 1
Assets:
Money market funds	24,157
Total	24,157
Liabilities:
Derivative liabilities	0	0
Total	0	0
Level 2
Assets:
Money market funds	0
Total	0
Liabilities:
Derivative liabilities	0	0
Total	0	0
Level 3
Assets:
Money market funds	0
Total	0
Liabilities:
Derivative liabilities	16	4,023
Total	$ 16	$ 4,023