Note 15 - Loss Per Share - Weighted Average Number of Shares Used in the Calculation of the Basic and Diluted Loss Per Share (Details) - USD ($)	3 Months Ended						9 Months Ended
	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Apr. 30, 2021	Apr. 30, 2020
Net loss for the period	$ (4,590,161)	$ (3,461,059)	$ (4,963,537)	$ (3,273,644)	$ (1,888,661)	$ (5,042,577)	$ (13,014,757)	$ (10,204,882)
Basic Weighted Average Number of Shares (in shares)	218,822,085			183,896,944			202,304,157	182,637,673
Dilutive Stock Options, RSUs, PRSUs and Warrants (in shares)
Diluted Weighted Average Number of Shares (in shares)	218,822,085			183,896,944			202,304,157	182,637,673
NET LOSS PER SHARE, BASIC AND DILUTED (in dollars per share)	$ (0.02)			$ (0.02)			$ (0.06)	$ (0.06)