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STOCK BASED COMPENSATION, ASSUMPTIONS USED IN DETERMINING THE FAIR VALUE (Details) - Stock Options
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Assumptions used principally in determining the fair value of options granted    
Risk-free interest rate (as a percent) 2.55%  
Expected dividend yield (as a percent) 0.00% 0.00%
Expected term 6 years 5 years 7 months 13 days
Expected volatility (as a percent) 105.00% 104.00%
Minimum    
Assumptions used principally in determining the fair value of options granted    
Risk-free interest rate (as a percent)   2.45%
Maximum    
Assumptions used principally in determining the fair value of options granted    
Risk-free interest rate (as a percent)   2.88%