Note 13 - Capital Stock - Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	6 Months Ended
	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020
Options Outstanding Outstanding (in shares)	13,070,468	14,171,250	15,514,750
Options Outstanding Weighted Average Exercise Price (in dollars per share)	$ 1.10	$ 1.10	$ 1.13
Options Outstanding Weighted Average Remaining Contractual Term (Year)	5 years 339 days
Options Exercisable (in shares)	8,034,311
Options Exercisable Weighted Average Exercise Price (in dollars per share)	$ 1.19
Options Exercisable Weighted Average Remaining Contractual Term (Year)	3 years 317 days
Exercise Price Range 1 [Member]
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 0.80
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 0.99
Options Outstanding Outstanding (in shares)	7,481,468
Options Outstanding Weighted Average Exercise Price (in dollars per share)	$ 0.92
Options Outstanding Weighted Average Remaining Contractual Term (Year)	7 years 200 days
Options Exercisable (in shares)	3,816,561
Options Exercisable Weighted Average Exercise Price (in dollars per share)	$ 0.92
Options Exercisable Weighted Average Remaining Contractual Term (Year)	5 years 357 days
Exercise Price Range 2 [Member]
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 1
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 1.49
Options Outstanding Outstanding (in shares)	3,587,000
Options Outstanding Weighted Average Exercise Price (in dollars per share)	$ 1.18
Options Outstanding Weighted Average Remaining Contractual Term (Year)	4 years 208 days
Options Exercisable (in shares)	2,215,750
Options Exercisable Weighted Average Exercise Price (in dollars per share)	$ 1.24
Options Exercisable Weighted Average Remaining Contractual Term (Year)	1 year 237 days
Exercise Price Range 3 [Member]
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 1.50
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 2.81
Options Outstanding Outstanding (in shares)	2,002,000
Options Outstanding Weighted Average Exercise Price (in dollars per share)	$ 1.65
Options Outstanding Weighted Average Remaining Contractual Term (Year)	2 years 105 days
Options Exercisable (in shares)	2,002,000
Options Exercisable Weighted Average Exercise Price (in dollars per share)	$ 1.65
Options Exercisable Weighted Average Remaining Contractual Term (Year)	2 years 105 days