Annual report pursuant to Section 13 and 15(d)

Derivative Liabilities - Assumptions used in Estimating Fair Value (Details)

v3.21.2
Derivative Liabilities - Assumptions used in Estimating Fair Value (Details)
May 31, 2021
USD ($)
May 31, 2020
USD ($)
May 31, 2019
$ / shares
Jan. 30, 2019
$ / shares
Nov. 15, 2018
USD ($)
$ / shares
Sep. 15, 2016
$ / shares
Warrant Derivative Liability | Grant Date Fair Value            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0.39     0.78
Warrant Derivative Liability | Risk Free Interest Rate            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0.0194     0.0120
Warrant Derivative Liability | Expected Term (In Years)            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     2.29     5
Warrant Derivative Liability | Stock Price Volatility            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0.61     1.06
Warrant Derivative Liability | Expected Dividend Yield            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0     0
Warrant Derivative Liability | Probability of Fundamental Transaction            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0.50     0.50
Warrant Derivative Liability | Probability of Holder Requesting Cash Payment            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Derivative Liability, Measurement Input     0.50     0.50
Redemption Provision Embedded Derivative | Grant Date Fair Value            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       0.49 0.57  
Redemption Provision Embedded Derivative | Risk Free Interest Rate            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       0.0252 0.0278  
Redemption Provision Embedded Derivative | Expected Term (In Years)            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       2 1.61  
Redemption Provision Embedded Derivative | Stock Price Volatility            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       0.61 0.588  
Redemption Provision Embedded Derivative | Expected Dividend Yield            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       0 0  
Redemption Provision Embedded Derivative | Discount Factor            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input       0.85 0.85  
Long Term Convertible Note January 2019            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Carrying value of Note | $ $ 0 $ 0        
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Grant Date Fair Value            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.39      
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Risk Free Interest Rate            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.0195      
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Expected Term (In Years)            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     1.67      
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Stock Price Volatility            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.622      
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Expected Dividend Yield            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0      
Long Term Convertible Note January 2019 | Redemption Provision Embedded Derivative | Discount Factor            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.85      
Long Term Convertible Note June 2018            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Carrying value of Note | $ $ 0 $ 0     $ 5,400,000  
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Grant Date Fair Value            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.39      
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Risk Free Interest Rate            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.0221      
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Expected Term (In Years)            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     1.07      
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Stock Price Volatility            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.622      
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Expected Dividend Yield            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0      
Long Term Convertible Note June 2018 | Redemption Provision Embedded Derivative | Discount Factor            
Fair Value Measurement Inputs and Valuation Techniques [Line Items]            
Embedded Derivative Liability, Measurement Input     0.85