Percentage of Net Product and Engineering Revenue from Major Customers (Detail) - Sales Revenue, Net - Largest customers	12 Months Ended
Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	61.00%	64.00%	66.00%
Philips
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	13.00%	14.00%	16.00%
L-3
Concentration Risk [Line Items]
Percentage of net product and engineering revenue		13.00%	11.00%
Toshiba
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	11.00%	11.00%	12.00%
Siemens AG
Concentration Risk [Line Items]
Percentage of net product and engineering revenue	12.00%	11.00%	11.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

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