Segment Information (Details) (USD $)	3 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Jul. 31, 2011
Number of reportable operating segments	3		3
Net sales	$ 113,361,000	$ 178,160,000
Operating Income (loss)	15,759,000	40,081,000
Interest income and other (expense)	496,000	694,000
Interest expense	2,146,000	2,063,000
Depreciation and amortization	5,012,000	6,333,000
Expenditure for long-lived assets, including intangibles	1,443,000	7,453,000
Total assets	853,373,000	1,028,853,000	937,509,000
Professional fees related to a contested proxy solicitation	2,638,000	0
Merger termination fee, net	0	12,500,000
Amortization of stock-based compensation	873,000	1,508,000
Telecommunications Transmission Segment [Member]
Net sales	56,796,000	49,141,000
Operating Income (loss)	13,034,000	8,320,000
Interest income and other (expense)	6,000	71,000
Interest expense	166,000	81,000
Depreciation and amortization	2,567,000	2,765,000
Expenditure for long-lived assets, including intangibles	1,271,000	6,973,000
Total assets	256,684,000	257,135,000
R F Microwave Amplifiers Segment [Member]
Net sales	21,113,000	22,800,000
Operating Income (loss)	323,000	637,000
Interest income and other (expense)	(3,000)	3,000
Interest expense	0	0
Depreciation and amortization	1,103,000	1,121,000
Expenditure for long-lived assets, including intangibles	106,000	79,000
Total assets	99,459,000	100,356,000
Mobile Data Communications Segment [Member]
Net sales	35,452,000	106,219,000
Operating Income (loss)	9,363,000	25,063,000
Interest income and other (expense)	9,000	12,000
Interest expense	0	0
Depreciation and amortization	420,000	872,000
Expenditure for long-lived assets, including intangibles	66,000	357,000
Total assets	29,935,000	60,485,000
Unallocated [Member]
Net sales	0	0
Operating Income (loss)	(6,961,000)	6,061,000
Interest income and other (expense)	484,000	608,000
Interest expense	1,980,000	1,982,000
Depreciation and amortization	922,000	1,575,000
Expenditure for long-lived assets, including intangibles	0	44,000
Total assets	467,295,000	610,877,000
Telecommunications Transmission Sales to RF Microwave Amplifiers [Member]
Intersegment sales	714,000	708,000
Telecommunications Transmissions Sales to Mobile Data Communications [Member]
Intersegment sales	3,490,000	6,651,000
RF Microwave Amplifiers Sales to Telecommunications Transmission [Member]
Intersegment sales	$ 2,000	$ 31,000