Note 13 - Capital Stock (Details Textual) - USD ($)		2 Months Ended	3 Months Ended			6 Months Ended
	Sep. 23, 2020	Mar. 16, 2021	Jan. 31, 2021	Oct. 31, 2020	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020	Jul. 31, 2020
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 1.93	$ 1.92		$ 1.93		$ 2.03
Share Price (in dollars per share)	$ 0.96
Class of Warrant or Right Exercised (in shares)			1,050
Proceeds from Stock Options Exercised			$ 212,125			$ 221,434
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)			559,528			573,060
Stock Issued During Period, Value, Stock Options Exercised			$ 212,125	$ 9,309
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value			7,093,519			$ 7,093,519
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value			3,740,946			3,740,946
Share-based Compensation Arrangement by Share-based Payment Award, Options, Unvested in Period, Intrinsic Value			3,352,573			3,352,573
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			1,241,072			$ 1,241,072
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						1 year 62 days
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			771,831			$ 771,831
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						1 year 58 days
Share-based Payment Arrangement, Expense			$ 271,834		$ 66,928	$ 543,668	$ 133,856
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			1,615,000			1,615,000		1,615,000
Performance-based Restriced Stock Units [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 164,264			$ 164,264
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						317 days
Share-based Payment Arrangement, Expense			$ 37,544		$ 68,165	$ 75,088	$ 136,330
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			333,750			333,750		333,750
Subsequent Event [Member]
Proceeds from Warrant Exercises		$ 511,726
Common Stock Issued During Period, Shares, Exercise of Warrants (in shares)		435,542
Class of Warrant or Right Exercised (in shares)		1,597,333
Proceeds from Stock Options Exercised		$ 381,631
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)		680,043
Stock Issued During Period, Value, Stock Options Exercised		$ 984,223
Warrant Issued with September 2020 Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 1.80
Warrants and Rights Outstanding, Term (Month)	2 years
Warrant Issued to Agents [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 1.80
Warrants and Rights Outstanding, Term (Month)	2 years
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	583,333
September 2020 Offering [Member]
Number of Units Issued During Period (in shares)	12,500,000
Shares Issued, Price Per Share (in dollars per share)	$ 1.20
Proceeds from Issuance or Sale of Equity, Total	$ 15,000,000
Number of Shares per Unit Issued (in shares)	1
Number of Warrants per Unit (in shares)	0.5
At-the-market Offering [Member]
Stock Offering, Maximum Amount			$ 30,000,000			$ 30,000,000
Stock Issued During Period, Shares, New Issues (in shares)			632,487
Proceeds from Issuance of Common Stock, Net			$ 1,074,337
At-the-market Offering [Member] | Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues (in shares)		13,036,419
Proceeds from Issuance of Common Stock, Net		$ 28,246,612
At-the-market Offering [Member] | Weighted Average [Member]
Shares Issued, Price Per Share (in dollars per share)			$ 1.74			$ 1.74
At-the-market Offering [Member] | Weighted Average [Member] | Subsequent Event [Member]
Shares Issued, Price Per Share (in dollars per share)		$ 2.22