COMMITMENTS AND CONTINGENCIES - Minimum Future Rental Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Minimum future rental payments under non-cancelable operating leases having remaining terms in excess of one year
2020	$ 127
2021	123
2022	118
2023	33
Total	401
Operating leases
Rental expense under all operating leases	$ 286	$ 309	$ 339