Note 12 - Capital Stock - Schedule of Outstanding Stock Options (Details)	3 Months Ended
	Oct. 31, 2020 $ / shares shares
Balance, number of stock options (in shares) | shares	15,514,750
Balance, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.13
Exercised, number of stock options (in shares) | shares	(28,500)
Exercised Options, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 0.93
Expired, number of stock options (in shares) | shares	(1,315,000)
Expired, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.43
Balance, number of stock options (in shares) | shares	14,171,250
Balance, Weighted Average Exercise Price (in dollars per share) | $ / shares	$ 1.10