Note 15 - Derivative Liabilities - Assumptions (Details)	Jul. 31, 2023 $ / shares	Jul. 31, 2022 $ / shares	Jul. 31, 2021 $ / shares	Jul. 31, 2020 $ / shares
Exercise Price (in dollars per share)	$ 3.31	$ 1.92	$ 1.90	$ 2.03
Replacement Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]
Derivative, measurement input	0.0525
Replacement Warrants [Member] | Measurement Input, Price Volatility [Member]
Derivative, measurement input	0.6443
Replacement Warrants [Member] | Measurement Input, Expected Term [Member]
Derivative, measurement input	1.11
Replacement Warrants [Member] | Measurement Input, Expected Dividend Rate [Member]
Derivative, measurement input	0.0000
Replacement Warrants [Member] | Minimum [Member]
Exercise Price (in dollars per share)	$ 2.44
Replacement Warrants [Member] | Maximum [Member]
Exercise Price (in dollars per share)	$ 3.36