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INVESTMENT IN EQUITY SECURITIES (Details Textual) - USD ($)
1 Months Ended 12 Months Ended
Jun. 30, 2015
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2015
Schedule of Investments [Line Items]          
Cost method investment   $ 0      
Fair value of investment       $ 0  
Loss on write down investment in equity securities   $ 0 $ 0 579,000  
Additional impairment loss         $ 26,000
Mevion Medical Systems Inc          
Schedule of Investments [Line Items]          
Fair value of investment $ 600,000       579,000
Loss on write down investment in equity securities $ 2,114,000     $ 579,000 $ 2,140,000