SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property and Equipment (Details)
12 Months Ended
Jun. 30, 2020
Testing equipment | Minimum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 3 years
Testing equipment | Maximum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 5 years
Computer and other equipment | Minimum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 3 years
Computer and other equipment | Maximum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 5 years
Furniture and fixtures | Minimum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 3 years
Furniture and fixtures | Maximum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 5 years
Software | Maximum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 3 years
Corporate aircraft | Maximum  
Property, Plant and Equipment [Line Items]  
Estimated Useful Life 15 years