SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment and Long-Lived Assets Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 28	$ 49
Impairment expense	$ 441	$ 0
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Contingent Consideration Liabilities
Property, Plant and Equipment [Line Items]
Change in fair value	$ (100)