Note 13 - Capital Stock - Schedule of Outstanding Unvested Stock Options (Details) - $ / shares	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Nonvested balance (in shares)	3,310,600	3,479,500	765,750
Nonvested, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.59	$ 0.68	$ 0.58
Granted, number of stock options (in shares)	6,163,900	2,006,350	4,083,000
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.45	$ 0.53	$ 0.68
Vested (in shares)	(2,590,154)	(2,055,250)	(1,303,000)
Vested, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.60	$ 0.68	$ 0.65
Cancelled/Forfeited (in shares)	(86,875)	(120,000)	(66,250)
Cancelled/Forfeited, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.43	$ 0.67	$ 0.62
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.45	$ 0.53	$ 0.68
Nonvested balance (in shares)	6,797,471	3,310,600	3,479,500
Nonvested, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.46	$ 0.59	$ 0.68