Cost Reduction Actions Wind-Down of Microsatellite Product Line (Details) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Restructuring Reserve [Roll Forward]
Restructuring reserve, noncurrent	$ 4,235,000
Wind-Down of Microsatellite Product Line [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	463,000
Pre-tax restructuring charge (benefit)	(56,000)	458,000	2,577,000
Payments made	(121,000)
Restructuring reserve, ending balance	286,000	463,000
Restructuring reserve, current	263,000
Restructuring reserve, noncurrent	23,000
Wind-Down of Microsatellite Product Line [Member] | Cost of Sales [Member]
Restructuring Reserve [Roll Forward]
Pre-tax restructuring charge (benefit)			1,270,000
Wind-Down of Microsatellite Product Line [Member] | Facility exit costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	413,000
Pre-tax restructuring charge (benefit)	(56,000)
Payments made	(121,000)
Restructuring reserve, ending balance	236,000
Wind-Down of Microsatellite Product Line [Member] | Other [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	50,000
Pre-tax restructuring charge (benefit)	0
Payments made	0
Restructuring reserve, ending balance	$ 50,000