Common stock options granted, forfeited or expired and exercised - Stock-Based Compensation (Details 1) (USD $)	9 Months Ended
Apr. 30, 2015	Apr. 30, 2015	Aug. 02, 2014
Options
Options Outstanding		30,333,074	37,964,390
Options Forfeited or expired	1,215,000
Options Exercised	6,416,316
Options Exercisable	30,333,074
Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share		0.048	0.061
Weighted Average Exercise Price per Share, Forfeited or expired	0.716
Weighted Average Exercise Price per Share, Exercised	0.001
Weighted Average Exercise Price per Share, Exercisable	0.048
Aggregate Intrinsic Vaalue
Options Outstanding		567,236
Options Exercised	129,908
Options Exercisable	567,236

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)-(4)

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Weighted average price of options that were either forfeited or expired.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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No definition available.

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Number of share options (or share units) exercised during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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