Customer and Geographic Information (Details) - USD ($)	12 Months Ended
Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Customer Concentration Risk [Member]
Revenue from External Customers [Line Items]
Minimum percentage of consolidated net sales sold to one customer or individual country requiring additional and separate disclosure	10.00%	10.00%	10.00%
U.S. government
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	30.60%	28.00%	34.70%
Commercial (United States)
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	13.20%	12.60%	15.20%
Total United States
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	43.80%	40.60%	49.90%
North African country
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	13.80%	15.40%	5.70%
Other international
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	42.40%	44.00%	44.40%
Total International
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	56.20%	59.40%	50.10%
Sales	$ 172,651,000	$ 205,993,000	$ 160,217,000
U.S. Prime Contractor [Member] \| Customer Concentration Risk [Member] \| Sales Revenue, Net [Member]
Revenue from External Customers [Line Items]
Percentage of revenue generated from external customer type	13.50%	15.40%

Percentage of revenue generated from a single external customer type.

No definition available.

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- Definition

The minimum percentage of consolidated net sales that, if made to one customer or country, would require additional and separate disclosure.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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