CASH AND CASH EQUIVALENTS - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
CASH AND CASH EQUIVALENTS
Cash and cash equivalents	$ 13,028	$ 19,031
Restricted cash included in other non-current assets	150	150
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 13,178	$ 19,181	$ 23,174	$ 19,603