Fair Value Assumptions Used in Accounting for Call Options (Details) - $ / shares	6 Months Ended
Jan. 31, 2018	Jan. 31, 2017	Jan. 18, 2017
Risk-free interest rate		1.34%	1.84%
Estimated volatility		143.90%	122.70%
Remaining Term		2 years 5 months	4 years 5 months
Stock price at valuation date	$ 3.75	$ 5.05
Call Option
Risk-free interest rate	2.14%
Estimated volatility	154.50%
Remaining Term	1 year 11 months
Stock price at valuation date	$ 3.75

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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- Definition

Risk-free interest rate assumption used in valuing an instrument.

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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

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