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STOCK OPTION PLAN AND STOCK-BASED COMPENSATION - Summary of Assumptions Used in Black Scholes Model to Estimate Fair Value of Stock Options (Details) - $ / shares
9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Stock Option Plan and Stock-Based Compensation    
Volatility   78.00%
Dividend yield 0.00% 0.00%
Weighted average grant date fair value per share of common stock $ 5.08 $ 5.53
Minimum    
Stock Option Plan and Stock-Based Compensation    
Expected term (years) 5 years 6 months 5 years 6 months
Risk free interest rate 1.83% 1.17%
Volatility 79.00%  
Maximum    
Stock Option Plan and Stock-Based Compensation    
Expected term (years) 6 years 3 months 6 years 3 months
Risk free interest rate 2.02% 1.52%
Volatility 84.00%  
Non-Employees Stock Options    
Stock Option Plan and Stock-Based Compensation    
Expected term (years)   9 years 10 months 24 days
Risk free interest rate   1.60%
Volatility   101.00%
Dividend yield 0.00% 0.00%
Weighted average grant date fair value per share of common stock $ 6.85 $ 12.76
Non-Employees Stock Options | Minimum    
Stock Option Plan and Stock-Based Compensation    
Expected term (years) 8 years 10 months 25 days  
Risk free interest rate 2.27%  
Volatility 111.00%  
Non-Employees Stock Options | Maximum    
Stock Option Plan and Stock-Based Compensation    
Expected term (years) 9 years 6 months  
Risk free interest rate 2.31%  
Volatility 112.00%