Accrued Expenses and Other Current Liabilities - Product Warranty Rollforward (Details) (USD $)	9 Months Ended
Apr. 30, 2015	Apr. 30, 2014
Accrued Liabilities, Current [Abstract]
Minimum coverage period of product warranty from the date of shipment	1 year
Changes in Product Warranty Liability
Accrued warranty obligations, as of the beginning of the period	$ 8,618,000	$ 7,797,000
Provision for warranty obligations	3,255,000	5,364,000
Charges incurred	(3,580,000)us-gaap_ProductWarrantyAccrualPayments	(4,176,000)us-gaap_ProductWarrantyAccrualPayments
Accrued warranty obligations, as of the end of the period	$ 8,293,000	$ 8,985,000

Minimum coverage period of product warranty from the date of shipment

No definition available.

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- Details

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers. For classified balance sheets, represents the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 25

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6397716&loc=d3e11281-110244

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12524-110249

+ Details

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- Definition

Represents the aggregate decrease in the liability related to payments to satisfy claims for standard and extended product warranties.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(2))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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- Definition

Represents the aggregate increase in the liability for accruals related to standard and extended product warranties issued during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(3))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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