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LIABILITIES PRESENTED AT FAIR VALUE, Warrants to Purchase Preferred Shares, Valuation Inputs (Details)
6 Months Ended 12 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Warrants to purchase preferred shares [Abstract]      
Risk-free interest rate 1.71% 2.50% 2.52%
Expected volatility 80.00% 90.00% 80.00%
Expected life 3 years 2 years 3 years 6 months
Expected dividend yield 0.00% 0.00% 0.00%