Valuation and Qualifying Accounts (Details) (USD $) In Thousands	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts
Beginning Balance	$ 462	$ 390	$ 558
Additions	17	265	138
Deductions	(173)	(193)	(306)
Ending Balance	306	462	390
Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts
Beginning Balance	225	520	347
Additions	458	166	972
Deductions	(397)	(461)	(799)
Ending Balance	286	225	520
Valuation Allowance Of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts
Beginning Balance	67,572	54,879	45,337
Additions	0	12,693	9,542
Deductions	(67,337)	0	0
Ending Balance	$ 235	$ 67,572	$ 54,879

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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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 09
-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

+ Details

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- Definition

+ References

+ Details

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- Definition

Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

+ References

+ Details

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