Note 12 - Stock-based Compensation - Schedule of Outstanding Un-vested Stock Options (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jan. 31, 2019
Nonvested balance (in shares)	2,650,500	3,479,500	3,479,500
Nonvested, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.67	$ 0.68	$ 0.68
Vested options (in shares)	(278,000)	(801,500)
Vested, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.69	$ 0.70
Forfeited options (in shares)		(27,500)
Forfeited, Weighted Average Grant-Date Fair Value (in dollars per share)		$ 0.67
Granted (in shares)	40,000
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.60
Nonvested balance (in shares)	2,412,500	2,650,500	2,412,500
Nonvested balance, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.67	$ 0.67	$ 0.67