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SHARE-BASED COMPENSATION (Details 4) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Risk-free interest rate 2.10% 1.50% 1.50%
Dividend yield 0.00% 0.00% 0.00%
Volatility factor 96.00% 101.70% 104.30%
Expected term (in years) 6 years 6 years 6 years
Weighted average estimated fair value per share $ 4.17 $ 13.32 $ 19.44