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Income taxes (Details) - Components of loss before income taxes (USD $)
In Thousands, unless otherwise specified |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
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Jul. 31, 2013
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Apr. 30, 2013
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Jan. 31, 2013
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Oct. 31, 2012
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Jul. 31, 2012
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Apr. 30, 2012
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Jan. 31, 2012
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Oct. 31, 2011
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Jul. 31, 2013
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Jul. 31, 2012
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Jul. 31, 2011
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| Income taxes (Details) - Components of loss before income taxes [Line Items] | |||||||||||
| Loss before taxes | $ (3,532) | $ (5,808) | $ (5,854) | $ (3,755) | $ (29,074) | $ (3,445) | $ (4,076) | $ (4,326) | $ (18,949) | $ (40,921) | $ (12,823) |
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Domestic Tax Authority [Member]
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| Income taxes (Details) - Components of loss before income taxes [Line Items] | |||||||||||
| Loss before taxes | (15,419) | (31,817) | (12,284) | ||||||||
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Foreign Tax Authority [Member]
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| Income taxes (Details) - Components of loss before income taxes [Line Items] | |||||||||||
| Loss before taxes | $ (3,530) | $ (9,104) | $ (539) | ||||||||