Stock-Based Compensation - Common stock options granted, forfeited or expired and exercised (Details) - USD ($)	9 Months Ended	12 Months Ended
	Apr. 30, 2021	Jul. 31, 2019
Share-based Payment Arrangement [Abstract]
Options Outstanding, Beginning	8,847,025
Options Granted	6,242,210
Options Forfeited or expired	(2,483,375)
Options Outstanding, End	12,605,860
Weighted Average Exercise Price per Share, Beginning	$ 0.9
Weighted Average Exercise Price per Share, Granted	0.35
Weighted Average Exercise Price per Share, Forfeited or expired	0.88
Weighted Average Exercise Price per Share, End	$ 0.63
Weighted Average Remaining Life Options Outstanding (Years)	7 years 26 days	5 years 11 months 15 days
Weighted Average Remaining Life Options Granted	9 years 3 months 26 days
Weighted Average Remaining Life Options Forfeited or expired	6 years 1 month 6 days
Aggregate Intrinsic Value Options, Outstanding Beginning	$ 508,206
Aggregate Intrinsic Value Options Granted	0
Aggregate Intrinsic Value Options, Outstanding Ending	195,507
Options outstanding, Non-vested Awards	$ 6,198,273