Note 3 - Acquisition of UEX Corporation - Replacement Warrant Assumptions (Details)	Jul. 31, 2023 $ / shares	Aug. 19, 2022 $ / 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] | UEX Acquisition [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] | Minimum [Member] | UEX Acquisition [Member]
Exercise Price (in dollars per share)		$ 1.11
Replacement Warrants [Member] | Minimum [Member] | UEX Acquisition [Member] | Measurement Input, Risk Free Interest Rate [Member]
Derivative, measurement input		0.0318
Replacement Warrants [Member] | Minimum [Member] | UEX Acquisition [Member] | Measurement Input, Price Volatility [Member]
Derivative, measurement input		0.9098
Replacement Warrants [Member] | Minimum [Member] | UEX Acquisition [Member] | Measurement Input, Expected Term [Member]
Derivative, measurement input		0.75
Replacement Warrants [Member] | Maximum [Member]
Exercise Price (in dollars per share)	$ 3.36
Replacement Warrants [Member] | Maximum [Member] | UEX Acquisition [Member]
Exercise Price (in dollars per share)		$ 3.42
Replacement Warrants [Member] | Maximum [Member] | UEX Acquisition [Member] | Measurement Input, Risk Free Interest Rate [Member]
Derivative, measurement input		0.0323
Replacement Warrants [Member] | Maximum [Member] | UEX Acquisition [Member] | Measurement Input, Price Volatility [Member]
Derivative, measurement input		1.0152
Replacement Warrants [Member] | Maximum [Member] | UEX Acquisition [Member] | Measurement Input, Expected Term [Member]
Derivative, measurement input		2.05