Segment Information (Details) (USD $)	3 Months Ended												12 Months Ended
	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2014 operating_segment	Jul. 31, 2013 operating_segment	Jul. 31, 2012 operating_segment
Segment Reporting Information
Number of operating segments													3	3	3
Segment Reporting Information, Profit (Loss)
Net sales	$ 89,378,000	$ 88,905,000	$ 85,499,000	$ 83,368,000	$ 84,411,000	$ 69,856,000	$ 74,577,000	$ 90,953,000	$ 112,775,000	$ 99,793,000	$ 99,141,000	$ 113,361,000	$ 347,150,000	$ 319,797,000	$ 425,070,000
Operating Income (loss)													43,898,000	34,489,000	51,277,000
Interest income and other (expense)													913,000	1,167,000	1,595,000
Interest expense													6,304,000	8,163,000	8,832,000
Depreciation and amortization													17,269,000	17,295,000	20,414,000
Expenditure for long-lived assets, including intangibles													4,937,000	5,347,000	6,413,000
Total assets	473,852,000				681,815,000				719,778,000				473,852,000	681,815,000	719,778,000
Benefit related to a change in fair value of contingent earn-out liability													239,000	3,267,000	918,000
Amortization of stock-based compensation													4,263,000	3,130,000	3,572,000
Telecommunications Transmission Sales to RF Microwave Amplifiers [Member]
Segment Reporting Information [Line Items]
Intersegment sales													1,726,000	2,312,000	5,378,000
Telecommunications Transmissions Sales to Mobile Data Communications [Member]
Segment Reporting Information [Line Items]
Intersegment sales													525,000	2,656,000	11,161,000
RF Microwave Amplifiers Sales to Telecommunications Transmission [Member]
Segment Reporting Information [Line Items]
Intersegment sales													137,000	9,000	382,000
Telecommunications Transmission Segment [Member]
Segment Reporting Information, Profit (Loss)
Net sales													231,462,000	194,643,000	210,006,000
Operating Income (loss)													40,779,000	31,686,000	41,709,000
Interest income and other (expense)													2,000	(38,000)	42,000
Interest expense													247,000	352,000	651,000
Depreciation and amortization													8,891,000	9,591,000	10,088,000
Expenditure for long-lived assets, including intangibles													4,060,000	4,179,000	5,490,000
Total assets	230,555,000				225,626,000				244,285,000				230,555,000	225,626,000	244,285,000
Benefit related to a change in fair value of contingent earn-out liability													239,000	3,267,000	918,000
RF Microwave Amplifiers Segment [Member]
Segment Reporting Information, Profit (Loss)
Net sales													87,977,000	86,939,000	102,497,000
Operating Income (loss)													4,533,000	4,104,000	7,622,000
Interest income and other (expense)													21,000	(42,000)	(21,000)
Interest expense													0	0	0
Depreciation and amortization													3,784,000	3,939,000	4,395,000
Expenditure for long-lived assets, including intangibles													561,000	842,000	733,000
Total assets	87,454,000				96,298,000				98,864,000				87,454,000	96,298,000	98,864,000
Mobile Data Communications Segment [Member]
Segment Reporting Information, Profit (Loss)
Net sales													27,711,000	38,215,000	112,567,000
Operating Income (loss)													13,131,000	12,288,000	19,924,000
Interest income and other (expense)													12,000	18,000	30,000
Interest expense													(3,000)	(7,000)	0
Depreciation and amortization													270,000	500,000	2,173,000
Expenditure for long-lived assets, including intangibles													299,000	317,000	190,000
Total assets	5,929,000				7,873,000				11,217,000				5,929,000	7,873,000	11,217,000
Pre-tax restructuring (benefit) charge related to the wind-down of microsatellite product line													(56,000)	458,000	2,577,000
Unallocated [Member]
Segment Reporting Information, Profit (Loss)
Net sales													0	0	0
Operating Income (loss)													(14,545,000)	(13,589,000)	(17,978,000)
Interest income and other (expense)													878,000	1,229,000	1,544,000
Interest expense													6,060,000	7,818,000	8,181,000
Depreciation and amortization													4,324,000	3,265,000	3,758,000
Expenditure for long-lived assets, including intangibles													17,000	9,000	0
Total assets	149,914,000				352,018,000				365,412,000				149,914,000	352,018,000	365,412,000
Costs related to a withdrawn contested proxy solicitation															2,638,000
Amortization of stock-based compensation													$ 4,263,000	$ 3,130,000	$ 3,572,000