PROPERTY AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Millions  | 
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2021  | 
Jun. 30, 2020  | 
Jun. 30, 2021  | 
Jun. 30, 2020  | 
|
| Property, Plant and Equipment [Abstract] | ||||
| Depreciation expense | $ 0.7 | $ 0.7 | $ 1.4 | $ 1.4 | 
| Impairment charges or write-offs | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 | 
| X | ||||||||||
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
- References No definition available. 
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| X | ||||||||||
- Definition The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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