Note 13 - Capital Stock - Summary of Stock Options Assumptions (Details) - $ / shares	12 Months Ended
Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.45	$ 0.53	$ 0.68
Share-based Payment Arrangement, Option [Member]
Expected Risk Free Interest Rate	0.40%	1.86%	2.24%
Expected Volatility	60.48%	65.62%	67.60%
Expected Life in Years (Year)	4 years 328 days	4 years 328 days	3 years 36 days
Expected Dividend Yield	0.00%	0.00%	0.00%
Granted, Weighted Average Grant-Date Fair Value (in dollars per share)	$ 0.45	$ 0.53	$ 0.68

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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