COMMITMENTS AND CONTINGENCIES - Leases expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating lease, weighted average remaining lease term	3 years 2 months 12 days
Operating lease costs	$ 240	$ 223
Variable lease costs	48	66
Total lease costs	$ 288	$ 289
Minimum
Operating lease liability discount rates (in percent)	3.99%
Maximum
Operating lease liability discount rates (in percent)	8.95%