Note 15 - Income Taxes - Components of Income (Loss) from Operations Before Income Taxes, by Tax Jurisdiction (Details) - USD ($)	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Income (loss) from operations before income taxes	$ (14,616,067)	$ (17,167,161)	$ (18,534,145)
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Income (loss) from operations before income taxes	(13,962,287)	(16,560,132)	(17,709,866)
Foreign Tax Authority [Member] | Canada Revenue Agency [Member]
Income (loss) from operations before income taxes	53,960	120,362	145,267
Foreign Tax Authority [Member] | Tax Administration of Paraguay [Member]
Income (loss) from operations before income taxes	$ (707,740)	$ (727,391)	$ (969,546)