Quarterly report pursuant to Section 13 or 15(d)

Warrants and Derivative Liabilities - Schedule of Input and Valuation Technique Used to Value Warrant Liabilities (Details)

v3.21.2
Warrants and Derivative Liabilities - Schedule of Input and Valuation Technique Used to Value Warrant Liabilities (Details)
Sep. 30, 2021
$ / shares
Jul. 31, 2021
$ / shares
Dec. 31, 2020
$ / shares
2021 Inducement Warrants      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share)   $ 0.15  
2021 Inducement Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share)   $ 0.15  
2021 Common Stock Warrants      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share) $ 0.09    
2021 Pre-Funded Warrants      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share) 0.09    
2021 Common Stock Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share) 0.09    
2018 Emerald Financing Warrants      
Class of Warrant or Right [Line Items]      
Underlying common stock price (in dollars per share) $ 0.11   $ 0.04
Dividend yield | 2021 Inducement Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   0.0000  
Dividend yield | 2021 Inducement Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   0.0000  
Dividend yield | 2021 Common Stock Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0000    
Dividend yield | 2021 Pre-Funded Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0000    
Dividend yield | 2021 Common Stock Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0000    
Dividend yield | 2018 Emerald Financing Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0000   0.0000
Volatility factor | 2021 Inducement Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   1.3787  
Volatility factor | 2021 Inducement Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   1.3787  
Volatility factor | 2021 Common Stock Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 1.3602    
Volatility factor | 2021 Pre-Funded Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 1.3506    
Volatility factor | 2021 Common Stock Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 1.3602    
Volatility factor | 2018 Emerald Financing Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 1.348   0.909
Risk-free interest rate | 2021 Inducement Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   0.0073  
Risk-free interest rate | 2021 Inducement Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input   0.0073  
Risk-free interest rate | 2021 Common Stock Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0101    
Risk-free interest rate | 2021 Pre-Funded Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0155    
Risk-free interest rate | 2021 Common Stock Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0101    
Risk-free interest rate | 2018 Emerald Financing Warrants      
Class of Warrant or Right [Line Items]      
Warrants and rights outstanding measurement input 0.0016   0.0014
Expected term (years) | 2021 Inducement Warrants      
Class of Warrant or Right [Line Items]      
Expected term (years)   5 years  
Expected term (years) | 2021 Inducement Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Expected term (years)   5 years  
Expected term (years) | 2021 Common Stock Warrants      
Class of Warrant or Right [Line Items]      
Expected term (years) 5 years    
Expected term (years) | 2021 Pre-Funded Warrants      
Class of Warrant or Right [Line Items]      
Expected term (years) 10 years    
Expected term (years) | 2021 Common Stock Warrants to Placement Agent      
Class of Warrant or Right [Line Items]      
Expected term (years) 5 years    
Expected term (years) | 2018 Emerald Financing Warrants      
Class of Warrant or Right [Line Items]      
Expected term (years) 1 year 4 months 17 days   2 years 1 month 17 days