Derivative Liabilities - Summary of (Loss) Gain on Derivative Liability (Details) - USD ($)
12 Months Ended
Apr. 30, 2020
Apr. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Day one loss due to derivative liabilities on convertible notes payable and warrants   $ (679,032)
Change in derivative liabilities   20,015,840
Gain (loss) from marked-to-market adjustments   10,556,846
Net gain (loss) on derivative liabilities $ 29,893,654