Note 14 - Capital Stock - Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	9 Months Ended
	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020
0.80 (in shares)	11,170,110	13,070,468	14,171,250	15,514,750
0.80 (in dollars per share)	$ 1.11	$ 1.10	$ 1.10	$ 1.13
0.80 (Year)	6 years 65 days
0.80 (in shares)	6,320,692
0.80 (in dollars per share)	$ 1.20
0.80 (Year)	3 years 350 days
Exercise Price Range 1 [Member]
0.80 (in dollars per share)	$ 0.80
0.80 (in dollars per share)	$ 0.99
0.80 (in shares)	6,577,995
0.80 (in dollars per share)	$ 0.92
0.80 (Year)	7 years 266 days
0.80 (in shares)	3,108,567
0.80 (in dollars per share)	$ 0.92
0.80 (Year)	6 years 102 days
Exercise Price Range 2 [Member]
0.80 (in dollars per share)	$ 1
0.80 (in dollars per share)	$ 1.49
0.80 (in shares)	2,752,625
0.80 (in dollars per share)	$ 1.17
0.80 (Year)	5 years 47 days
0.80 (in shares)	1,415,125
0.80 (in dollars per share)	$ 1.25
0.80 (Year)	1 year 120 days
Exercise Price Range 3 [Member]
0.80 (in dollars per share)	$ 1.50
0.80 (in dollars per share)	$ 2.81
0.80 (in shares)	1,839,490
0.80 (in dollars per share)	$ 1.68
0.80 (Year)	2 years 76 days
0.80 (in shares)	1,797,000
0.80 (in dollars per share)	$ 1.66
0.80 (Year)	2 years 10 days