Note 12 - Stock-based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
	$ 747,342	$ 974,095	$ 1,588,866	$ 1,614,774
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total			529,492	616,468
Settlement of share issuance obligation				(127,615)
Consultants [Member]
Common stock issued for consulting services	229,806	157,599	360,610	438,778
Amortization of stock option expenses	30,319	341,788	84,720	341,619
	260,125	499,387	445,330	780,397
Management [Member]
Amortization of stock option expenses	139,900	86,650	356,704	180,981
	175,539	120,880	427,687	250,225
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total	35,639	34,230	70,983	69,244
Employees [Member]
Amortization of stock option expenses	186,806	152,114	467,154	334,731
	311,678	353,828	715,849	711,767
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures, Total	$ 124,872	$ 201,714	$ 248,695	$ 377,036