Annual report pursuant to Section 13 and 15(d)

Goodwill and intangible assets (Details) - Schedule of Intangible Assets

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Goodwill and intangible assets (Details) - Schedule of Intangible Assets (USD $)
In Thousands, unless otherwise specified
Jul. 31, 2013
Jul. 31, 2012
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross $ 28,214 $ 27,904
Finite-lived intangible assets, Accumulated Amortization (18,271) (16,124)
Finite-lived intangible assets, Net 9,943 11,780
Patents [Member]
    
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross 11,027 11,027
Finite-lived intangible assets, Accumulated Amortization (10,587) (10,439)
Finite-lived intangible assets, Net 440 588
Customer Relationships [Member]
    
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross 12,446 12,304
Finite-lived intangible assets, Accumulated Amortization (5,448) (4,356)
Finite-lived intangible assets, Net 6,998 7,948
Website And Acquired Content [Member]
    
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross 1,026 1,019
Finite-lived intangible assets, Accumulated Amortization (980) (874)
Finite-lived intangible assets, Net 46 145
Licensed Technology And Other [Member]
    
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross 513 485
Finite-lived intangible assets, Accumulated Amortization (382) (300)
Finite-lived intangible assets, Net 131 185
Trademarks [Member]
    
Goodwill and intangible assets (Details) - Schedule of Intangible Assets [Line Items]    
Finite-lived intangible assets, Gross 3,202 3,069
Finite-lived intangible assets, Accumulated Amortization (874) (155)
Finite-lived intangible assets, Net $ 2,328 $ 2,914