SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Valuation Input for Warrant and Derivative Liabilities (Details)
Dec. 31, 2019
$ / shares
year
Dec. 25, 2019
$ / shares
year
Sep. 30, 2019
month
May 17, 2019
$ / shares
year
May 01, 2019
$ / shares
year
Mar. 18, 2019
$ / shares
year
Mar. 08, 2019
month
$ / shares
Dec. 31, 2018
month
$ / shares
Jan. 29, 2018
Expected dividend yield                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs 0.000           0.000 0.000  
Warrants, measurement input                 0
Discount rate                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs 0.291           0.293 0.136  
Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs 0.960           1.011 1.056  
Warrants, measurement input                 0.848
Risk-free interest rate                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs 0.016           0.025 0.025  
Warrants, measurement input                 0.025
Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs | month     14       24 21  
Price of the underlying common stock (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Derivative liability, measurement inputs 0.56           1.99 2.31  
Short-Term Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 4.00         4.00      
Short-Term Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.976         1.220      
Short-Term Warrants | Risk-free interest rate                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.015         0.025      
Short-Term Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year 0.25         1      
Short-Term Warrants | Price of the underlying common stock (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.56         2.48      
Long-Term Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input       2.13   2.56      
Long-Term Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input       0.834   0.852      
Long-Term Warrants | Risk-free interest rate                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.017     0.022   0.022      
Long-Term Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year           5      
Long-Term Warrants | Price of the underlying common stock (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.56     1.58   2.48      
Exchange Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input         0.841        
Exchange Warrants | Risk-free interest rate                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   0.017     0.022        
Exchange Warrants | Price of the underlying common stock (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   0.56     1.54        
Minimum | Long-Term Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 2.13                
Minimum | Long-Term Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.873                
Minimum | Long-Term Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year 4.2     5          
Minimum | Exchange Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   2.13     2.13        
Minimum | Exchange Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   0.873              
Minimum | Exchange Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year   4.4     5        
Maximum | Long-Term Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 2.56                
Maximum | Long-Term Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input 0.893                
Maximum | Long-Term Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year 4.3                
Maximum | Exchange Warrants | Conversion price (in dollars per share)                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   2.53     2.53        
Maximum | Exchange Warrants | Expected stock price volatility                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input   0.889              
Maximum | Exchange Warrants | Expected term                  
Fair Value Measurement Inputs and Valuation Techniques [Line Items]                  
Warrants, measurement input | year   4.9     5.5