OTHER SUPPLEMENTAL INFORMATION - Other long-term liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
OTHER SUPPLEMENTAL INFORMATION
Long-term lease liability	$ 2,939
Liability for uncertain tax positions.	1,030	$ 967
Other long-term liabilities	59	429
Total	$ 4,028	$ 1,396