Note 12 - Stock-based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Shares Issued Under Stock Incentive Plan, Issuance Value			$ 785,117	$ 729,644
	$ 554,732	$ 518,585	2,143,598	2,133,359
Settlement of share issuance obligation				(127,615)
Consultants [Member]
Common stock issued for consulting services	155,813	168,107	516,423	606,885
Amortization of stock option expenses	37,336	43,463	122,056	385,082
	193,149	211,570	638,479	991,967
Management [Member]
Shares Issued Under Stock Incentive Plan, Issuance Value	33,126	34,265	104,109	103,509
Amortization of stock option expenses	70,395	45,926	427,099	226,907
	103,521	80,191	531,208	330,416
Employees [Member]
Shares Issued Under Stock Incentive Plan, Issuance Value	132,638	120,711	381,333	497,747
Amortization of stock option expenses	125,424	106,113	592,578	440,844
	$ 258,062	$ 226,824	$ 973,911	$ 938,591