ACCOUNTS PAYABLE, ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES - Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Jan. 01, 2019
Other current liabilities
Operating lease liabilities	$ 8,186	$ 11,398	$ 16,700
Other	2,563	3,326
Total	$ 10,749	$ 14,724