INCOME TAXES - Summary of Operating Loss and Tax Credit Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
NOL Carryforwards
Tax credit carryforwards	$ 14,555	$ 14,555
Foreign Tax Authority
NOL Carryforwards
Net operating loss carryforwards		3,262
State and Local Jurisdiction
NOL Carryforwards
Net operating loss carryforwards	2,983	1,175
Previous | Domestic Tax Authority
NOL Carryforwards
Net operating loss carryforwards	2,363	2,363
Post | Domestic Tax Authority
NOL Carryforwards
Net operating loss carryforwards	$ 13,017	$ 1,872