Note 13 - Stock-based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($)	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
	$ 2,948,041	$ 3,504,058	$ 3,769,370
Common stock issued	1,361,944	1,711,579	1,584,394
Settlement of share issuance obligation		(127,615)
Consultants [Member]
Common stock issued for consulting services	644,307	740,640	1,184,660
Amortization of stock option expenses	153,549	582,842	469,815
	797,856	1,323,482	1,654,475
Management [Member]
Amortization of stock option expenses	516,266	284,556	473,811
	785,954	987,061	1,160,395
Common stock issued	269,688	702,505	686,584
Employees [Member]
Amortization of stock option expenses	689,743	547,231	369,663
	1,364,231	1,321,130	954,500
Common stock issued	$ 674,488	$ 773,899	$ 584,837