SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and equipment useful lives (Details)	Dec. 31, 2023
Research and development equipment
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Autos
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	7 years