CASH, CASH EQUIVALENTS, AND INVESTMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 20,603	$ 33,222	$ 1,068
Restricted cash included in Other current assets	150	0	0
Restricted cash included in Other current, net	486	482	481
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 21,239	$ 33,704	$ 1,549	$ 8,470