Note 13 - Capital Stock - Number of Shares Issued and Cash Received upon Exercise of the Stock Options (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jan. 31, 2021	Oct. 31, 2020	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Number of Options Exercised on Forfeiture Basis (in shares)	923,282			941,782
Number of Options Exercised on Cash Basis (in shares)	177,500			187,500
Total Number of Options Exercised (in shares)	1,100,782	28,500		1,129,282
Number of Shares Issued on Cash Exercise (in shares)	177,500			187,500
Number of Shares Issued on Forfeiture Basis (in shares)	382,028			385,560
Total Number of Shares Issued Upon Exercise of Options (in shares)	559,528			573,060
Cash Received from Exercise of Stock Options	$ 212,125			$ 221,434
Total Intrinsic Value of Options Exercised	$ 822,237			$ 828,615