Note 12 - Capital Stock - Warrants Outstanding and Exercisable (Details) - $ / shares	3 Months Ended
	Oct. 31, 2021	Jul. 31, 2021
Weighted Average Exercise Price (in dollars per share)	$ 1.91	$ 1.90
Number of Warrants Outstanding (in shares)	4,895,474	5,387,323
Weighted Average Remaining Contractual Life (Year)	1 year 7 days
Warrants 1 [Member]
Number of Warrants Outstanding (in shares)	221,546
Weighted Average Remaining Contractual Life (Year)	9 months 7 days
Expiry Date	Aug. 09, 2022
Warrants 2 [Member]
Number of Warrants Outstanding (in shares)	4,467,110
Weighted Average Remaining Contractual Life (Year)	10 months 24 days
Expiry Date	Sep. 23, 2022
Warrants 3 [Member]
Number of Warrants Outstanding (in shares)	25,000
Weighted Average Remaining Contractual Life (Year)	1 year 6 months 18 days
Expiry Date	May 21, 2023
Warrants 4 [Member]
Number of Warrants Outstanding (in shares)	181,818
Weighted Average Remaining Contractual Life (Year)	4 years 5 months 4 days
Expiry Date	Apr. 05, 2026