Note 13 - Capital Stock - Warrants Outstanding and Exercisable (Details) - $ / shares	6 Months Ended
	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020
Weighted Average Exercise Price (in dollars per share)	$ 1.93	$ 1.92	$ 2.03
Number of Warrants Outstanding (in shares)	14,254,264	14,555,314	7,721,981
Warrants 1 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.05
Number of Warrants Outstanding (in shares)	7,063,253
Weighted Average Remaining Contractual Life (Year)	62 days
Expiry Date	Apr. 03, 2021
Warrants 2 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 2.30
Number of Warrants Outstanding (in shares)	308,728
Weighted Average Remaining Contractual Life (Year)	1 year 189 days
Expiry Date	Aug. 09, 2022
Warrants 3 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.64
Number of Warrants Outstanding (in shares)	50,000
Weighted Average Remaining Contractual Life (Year)	2 years 109 days
Expiry Date	May 21, 2023
Warrants 4 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.80
Number of Warrants Outstanding (in shares)	6,832,283
Weighted Average Remaining Contractual Life (Year)	1 year 233 days
Expiry Date	Sep. 23, 2022
Warrants 5 [Member]
Weighted Average Exercise Price (in dollars per share)	$ 1.93
Number of Warrants Outstanding (in shares)	14,254,264
Weighted Average Remaining Contractual Life (Year)	332 days
Expiry Date