Segment Information (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Jul. 31, 2012
Number of reportable operating segments	3		3		3
Net sales	$ 74,577,000	$ 99,141,000	$ 165,530,000	$ 212,502,000
Operating income (loss)	5,947,000	10,654,000	19,309,000	26,413,000
Interest income and other (expense)	315,000	434,000	591,000	930,000
Interest expense (income)	2,030,000	2,183,000	4,141,000	4,329,000
Depreciation and amortization	4,382,000	5,089,000	8,734,000	10,101,000
Expenditure for long-lived assets, including intangibles	1,394,000	1,217,000	2,457,000	2,660,000
Total assets	684,747,000	765,400,000	684,747,000	765,400,000	719,778,000
Benefit related to a change in fair value of contingent earn-out liability			3,267,000	0
Amortization of stock-based compensation	806,000	1,036,000	1,551,000	1,909,000
Telecommunications Transmission Segment [Member]
Net sales	45,769,000	51,328,000	99,096,000	108,124,000
Operating income (loss)	5,549,000	8,319,000	17,808,000	21,353,000
Interest income and other (expense)	(26,000)	14,000	(35,000)	20,000
Interest expense (income)	80,000	166,000	239,000	332,000
Depreciation and amortization	2,427,000	2,507,000	4,863,000	5,074,000
Expenditure for long-lived assets, including intangibles	1,228,000	799,000	2,069,000	2,070,000
Total assets	226,656,000	241,369,000	226,656,000	241,369,000
Benefit related to a change in fair value of contingent earn-out liability	889,000		3,267,000
RF Microwave Amplifiers Segment [Member]
Net sales	20,362,000	22,437,000	45,651,000	43,550,000	102,497,000
Operating income (loss)	645,000	1,195,000	2,363,000	1,518,000
Interest income and other (expense)	(7,000)	(3,000)	(29,000)	(6,000)
Interest expense (income)	0	0	0	0
Depreciation and amortization	977,000	1,101,000	1,957,000	2,204,000
Expenditure for long-lived assets, including intangibles	135,000	369,000	342,000	475,000
Total assets	93,208,000	103,445,000	93,208,000	103,445,000
Mobile Data Communications Segment [Member]
Net sales	8,446,000	25,376,000	20,783,000	60,828,000
Operating income (loss)	2,994,000	4,408,000	6,465,000	13,771,000
Interest income and other (expense)	3,000	7,000	12,000	16,000
Interest expense (income)	(6,000)	0	(6,000)	0
Depreciation and amortization	134,000	397,000	286,000	817,000
Expenditure for long-lived assets, including intangibles	26,000	49,000	41,000	115,000
Total assets	10,651,000	25,160,000	10,651,000	25,160,000
Restructuring charge related to the wind-down of microsatellite product line	(253,000)		569,000
Unallocated [Member]
Net sales	0	0	0	0
Operating income (loss)	(3,241,000)	(3,268,000)	(7,327,000)	(10,229,000)
Interest income and other (expense)	345,000	416,000	643,000	900,000
Interest expense (income)	1,956,000	2,017,000	3,908,000	3,997,000
Depreciation and amortization	844,000	1,084,000	1,628,000	2,006,000
Expenditure for long-lived assets, including intangibles	5,000	0	5,000	0
Total assets	354,232,000	395,426,000	354,232,000	395,426,000
Costs Related to a withdrawn contested proxy solicitation				2,638,000
Amortization of stock-based compensation	806,000	1,036,000	1,551,000	1,909,000
Telecommunications Transmission Sales to RF Microwave Amplifiers [Member]
Intersegment sales	423,000	985,000	1,657,000	1,699,000
Telecommunications Transmissions Sales to Mobile Data Communications [Member]
Intersegment sales	$ 112,000	$ 1,400,000	$ 2,619,000	$ 4,890,000