Cost Reduction Actions (Details) (USD $)	1 Months Ended	3 Months Ended			9 Months Ended		30 Months Ended
	Aug. 31, 2009	Apr. 30, 2011	Apr. 30, 2010	Oct. 31, 2008	Apr. 30, 2011	Apr. 30, 2010	Apr. 30, 2011
Cost Reduction Actions
Proceeds from sale of a small product line	$ 2,038,000
Business acquisition restructuring costs, total estimated costs				2,713,000
Business acquisition restructuring costs related to severance for employees				613,000
Total non-cancelable lease obligations				12,741,000
Less: Estimated sublease income				(8,600,000)
Total net estimated facility-related exit costs		4,073,000		4,141,000	4,073,000		4,073,000
Less: Interest expense to be accreted				(2,041,000)
Present value of estimated facility-related exit costs		2,420,000		2,100,000	2,420,000		2,420,000
Radyne lease expiration date				Oct. 31, 2018
Radyne sublease expiration date				Oct. 31, 2015
Present value of estimated facility-related exit costs, beginning balance				2,100,000	2,136,000		2,100,000
Cash payments made					(736,000)		(3,050,000)
Cash payments received					901,000		2,982,000
Interest accreted on the facility-related exit costs		41,000	34,000		119,000	113,000	388,000
Present value of estimated facility-related exit costs, ending balance		2,420,000		2,100,000	2,420,000		2,420,000
Amount of facility-related exit cost liability recorded as prepaid expenses		395,000			395,000		395,000
Facility-related exit cost liability, Noncurrent		2,815,000			2,815,000		2,815,000
Less expected net cash to be received in next twelve months		(395,000)			(395,000)		(395,000)
Interest expense to be accreted in future periods		$ 1,653,000			$ 1,653,000		$ 1,653,000