Cost Reduction Actions Wind-Down of Microsatellite Product Line (Details) (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Restructuring reserve, noncurrent	$ 4,117,000		$ 4,117,000
Wind-Down of Microsatellite Product Line [Member]
Restructuring reserve, current	252,000		252,000
Restructuring reserve, noncurrent	58,000		58,000
Restructuring Reserve [Roll Forward]
Restructuring reserve - beginning balance			463,000
Pre-tax restructuring charge (benefit)	(56,000)	0	(56,000)	569,000
Payments made			(97,000)
Restructuring reserve - ending balance	310,000		310,000
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			(97,000)
Restructuring reserve - ending balance	260,000		260,000
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		$ 50,000