Note 6 - Equity-accounted Investment (Details Textual) - Uranium Royalty Corp [Member] - USD ($) $ in Millions		12 Months Ended
	Dec. 04, 2018	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2018
Equity Method Investment, Shares Owned (in shares)		14,000,000
Equity Method Investment, Ownership Percentage		32.60%	19.50%	11.30%
Equity Method Investments, Fair Value Disclosure			$ 12.1
Royalty Purchase Agreement [Member]
Number Of Shares Acquired Through Sale Of Royalties (in shares)	12,000,000	12,000,000