Note 12 - Stock-based Compensation - Schedule of Outstanding Stock Options (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jan. 31, 2019
Balance outstanding (in shares)	14,700,625	14,911,625	14,911,625
Balance, Weighted Average Exercise Price (in dollars per share)	$ 1.41	$ 1.41	$ 1.41
Exercised (in shares)	(25,000)	(183,500)	(117,386)
Exercised Options, Weighted Average Exercise Price (in dollars per share)	$ 0.45	$ 1.19
Forfeited (in shares)	(12,500)	(27,500)
Forfeited, Weighted Average Exercise Price (in dollars per share)	$ 1.33	$ 1.44
Granted (in shares)	40,000
Granted, Weighted Average Exercise Price (in dollars per share)	$ 1.25
Balance outstanding (in shares)	14,703,125	14,700,625	14,703,125
Balance, Weighted Average Exercise Price (in dollars per share)	$ 1.41	$ 1.41	$ 1.41