Commitments and Contingencies (Details) (USD $) In Thousands	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Future minimum lease payments under non-cancelable operating leases
2012	$ 4,823
2013	4,414
2014	3,969
2015	3,892
2016	3,336
Total minimum payments	20,434
Changes in the warranty liability
Beginning Balance	210	158	125
Provision	462	266	256
Obligations fulfilled during period	(268)	(214)	(223)
Ending Balance	$ 404	$ 210	$ 158

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The total of future contractually required payments on leases defined as operating.

+ References

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 13
-Paragraph 122
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-Name Accounting Standards Codification
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For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within one year of the balance sheet date relating to leases defined as operating.

+ References

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For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fifth year of the balance sheet date relating to leases defined as operating.

+ References

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Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
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-Paragraph 14
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Represents the aggregate decrease in the liability for payments made (in cash or in kind) to satisfy claims under the terms of the standard product warranty. Does not include any Increase or Decrease in the liability for payments related to extended product warranties.

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Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting standard product warranties (including adjustments related to changes in estimates). Does not include any Increase or Decrease in the liability for accruals related to extended product warranties.

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