Note 6 - Restricted Cash - Restricted Cash (Details) - USD ($)	12 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Restricted cash, beginning of period	$ 1,839,216	$ 1,821,392
Additional surety bond collateral	198,377
Interest received	84	17,824
Restricted cash, end of period	$ 2,037,677	$ 1,839,216