Note 11 - Capital Stock (Details Textual) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 03, 2018	Mar. 10, 2019	Jan. 31, 2019	Oct. 31, 2018	Jan. 31, 2019	Jul. 31, 2018
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 2		$ 2	$ 1.97
Share Price	$ 1.54
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises on a Forfeiture Basis			25,000	117,250	142,250
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			16,964	34,172
October 2018 Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 2.05
Warrants and Rights Outstanding, Term	2 years 180 days
October 2018 Warrants [Member] | Subsequent Event [Member]
Proceeds from Warrant Exercises		$ 2,325,740
Class of Warrant or Right, Exercised During Period		1,938,117
Class of Warrant or Right, Exercised During Period, Exercise Price		$ 1.20
Equity Financing [Member]
Number of Units Issued During Period	12,613,049
Shares Issued, Price Per Share	$ 1.60		$ 1.60		$ 1.60
Proceeds from Issuance or Sale of Equity, Total	$ 20,180,878
Number of Shares per Unit Issued	1
Number of Warrants per Unit	0.5
Over-Allotment Option [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 2.05
Warrants and Rights Outstanding, Term	2 years 180 days
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	756,782