Segment Information (Details) (USD $)	3 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Jul. 31, 2012
Number of reportable operating segments	3		3
Net sales	$ 90,953,000	$ 113,361,000
Operating income (loss)	13,362,000	15,759,000
Interest income and other (expense)	276,000	496,000
Interest expense	2,111,000	2,146,000
Depreciation and amortization	4,352,000	5,012,000
Expenditure for long-lived assets, including intangibles	1,063,000	1,443,000
Total assets	705,594,000	853,373,000	719,778,000
Benefit related to a change in fair value of contingent earn-out liability	2,378,000	0
Amortization of stock-based compensation	745,000	873,000
Telecommunications Transmission Segment [Member]
Net sales	53,327,000	56,796,000
Operating income (loss)	12,259,000	13,034,000
Interest income and other (expense)	(9,000)	6,000
Interest expense	159,000	166,000
Depreciation and amortization	2,436,000	2,567,000
Expenditure for long-lived assets, including intangibles	841,000	1,271,000
Total assets	233,446,000	256,684,000
Benefit related to a change in fair value of contingent earn-out liability	2,378,000
RF Microwave Amplifiers Segment [Member]
Net sales	25,289,000	21,113,000
Operating income (loss)	1,718,000	323,000
Interest income and other (expense)	(22,000)	(3,000)
Interest expense	0	0
Depreciation and amortization	980,000	1,103,000
Expenditure for long-lived assets, including intangibles	207,000	106,000
Total assets	95,785,000	99,459,000
Mobile Data Communications Segment [Member]
Net sales	12,337,000	35,452,000
Operating income (loss)	3,471,000	9,363,000
Interest income and other (expense)	9,000	9,000
Interest expense	0	0
Depreciation and amortization	152,000	420,000
Expenditure for long-lived assets, including intangibles	15,000	66,000
Total assets	8,511,000	29,935,000
Microsatellite product line sales included in mobile data communications segment	883,000
Restructuring charge related to the wind-down of microsatellite product line	822,000
Unallocated [Member]
Net sales	0	0
Operating income (loss)	(4,086,000)	(6,961,000)
Interest income and other (expense)	298,000	484,000
Interest expense	1,952,000	1,980,000
Depreciation and amortization	784,000	922,000
Expenditure for long-lived assets, including intangibles	0	0
Total assets	367,852,000	467,295,000
Costs Related to a withdrawn contested proxy solicitation		2,638,000
Amortization of stock-based compensation	745,000	873,000
Telecommunications Transmission Sales to RF Microwave Amplifiers [Member]
Intersegment sales	1,234,000	714,000
Telecommunications Transmissions Sales to Mobile Data Communications [Member]
Intersegment sales	$ 2,507,000	$ 3,490,000