INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Provision for (benefit from) income taxes	$ (1,000)	$ (1,000)
Increase of valuation allowance	7,700,000	9,100,000
Federal net operating loss carryforwards	125,500,000
State net operating loss carryforwards	127,900,000
Tax cuts and jobs act of 2017, federal net operating loss carryforwards	$ 78,700,000
Percentage of tax cuts and jobs act of 2017, federal net operating loss carryforwards	80.00%
Operating loss carryforwards that will expire	$ 0
Interest
Penalties	0	0
Unrecognized tax benefits	0	0
Significant uncertain tax positions	1,000,000.0	$ 0
Switzerland
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 40,000