SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Valuation Input for Warrant and Derivative Liabilities (Details)
May 04, 2020
$ / shares
Feb. 11, 2020
$ / shares
year
Jan. 10, 2020
$ / shares
year
Jan. 06, 2020
$ / shares
year
May 01, 2019
$ / shares
year
Mar. 08, 2019
year
$ / shares
Discount rate            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input     0.216     0.293
Conversion price            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input 0.5894          
Conversion price | Short-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   4.00        
Conversion price | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input       2.13    
Expected stock price volatility            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input     1.039     1.011
Warrants and rights outstanding, measurement input 0.737          
Expected stock price volatility | Short-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.971        
Expected stock price volatility | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input       0.873 0.841  
Risk-free interest rate            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input     0.016     0.025
Warrants and rights outstanding, measurement input 0.004          
Risk-free interest rate | Short-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.016        
Risk-free interest rate | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.017        
Risk-free interest rate | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input       0.017 0.022  
Expected term            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year     2     2
Expected term | Short-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year   0.58        
Expected term | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year   4.2        
Expected term | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year       4.9    
Price of the underlying common stock            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input     0.65     1.99
Warrants and rights outstanding, measurement input 0.50          
Price of the underlying common stock | Short-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.79        
Price of the underlying common stock | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.79        
Price of the underlying common stock | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input       0.58 1.54  
Minimum | Conversion price | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   2.13        
Minimum | Conversion price | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input         2.13  
Minimum | Expected stock price volatility | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.879        
Minimum | Expected term | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year         5  
Maximum | Conversion price | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   2.56        
Maximum | Conversion price | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input         2.53  
Maximum | Expected stock price volatility | Long-term Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Warrants and rights outstanding, measurement input   0.892        
Maximum | Expected term | Exchange Warrants            
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]            
Derivative liability, measurement input | year         5.5