Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Jun. 30, 2013
Segment Reporting Information [Line Items]
Sales to external customers	$ 15,716,000	$ 11,243,000	$ 53,668,000	$ 39,921,000
Intersegment sales	0	0	0	0
Depreciation and amortization	419,000	402,000	1,222,000	1,253,000
Income (loss) before income taxes	3,624,000	1,977,000	12,470,000	7,102,000
Fixed asset additions	377,000	102,000	1,230,000	556,000
Segment assets	83,013,000		83,013,000		83,086,000
Goodwill	17,227,000		17,227,000		17,227,000
Other intangible assets	6,375,000		6,375,000		6,967,000
Seismic Energy Sources [Member]
Segment Reporting Information [Line Items]
Sales to external customers	4,786,000	4,687,000	18,947,000	17,263,000
Intersegment sales	199,000	0	926,000	0
Depreciation and amortization	77,000	49,000	215,000	150,000
Income (loss) before income taxes	810,000	1,371,000	5,067,000	3,918,000
Fixed asset additions	220,000	4,000	336,000	58,000
Segment assets	18,294,000		18,294,000		23,140,000
Goodwill	0		0		0
Other intangible assets	117,000		117,000		100,000
Underwater Cables and Connectors [Member]
Segment Reporting Information [Line Items]
Sales to external customers	3,761,000	3,845,000	13,355,000	11,964,000
Intersegment sales	67,000	111,000	321,000	269,000
Depreciation and amortization	81,000	75,000	232,000	220,000
Income (loss) before income taxes	1,529,000	1,478,000	5,271,000	4,538,000
Fixed asset additions	43,000	28,000	647,000	391,000
Segment assets	16,230,000		16,230,000		18,757,000
Goodwill	7,679,000		7,679,000		7,679,000
Other intangible assets	0		0		0
Seismic Energy Source Controllers [Member]
Segment Reporting Information [Line Items]
Sales to external customers	755,000	252,000	3,801,000	1,845,000
Intersegment sales	198,000	211,000	739,000	447,000
Depreciation and amortization	20,000	42,000	56,000	181,000
Income (loss) before income taxes	270,000	(1,000)	1,842,000	561,000
Fixed asset additions	29,000	0	109,000	2,000
Segment assets	6,110,000		6,110,000		5,716,000
Goodwill	3,278,000		3,278,000		3,278,000
Other intangible assets	304,000		304,000		325,000
Underwater Robotic Vehicles [Member]
Segment Reporting Information [Line Items]
Sales to external customers	6,414,000	2,459,000	17,565,000	8,849,000
Intersegment sales	0	0	0	0
Depreciation and amortization	237,000	231,000	705,000	688,000
Income (loss) before income taxes	2,022,000	13,000	3,152,000	796,000
Fixed asset additions	85,000	70,000	138,000	105,000
Segment assets	23,485,000		23,485,000		22,724,000
Goodwill	6,270,000		6,270,000		6,270,000
Other intangible assets	5,954,000		5,954,000		6,542,000
Corporate Headquarters and Eliminations [Member]
Segment Reporting Information [Line Items]
Sales to external customers	0	0	0	0
Intersegment sales	(464,000)	(322,000)	(1,986,000)	(716,000)
Depreciation and amortization	4,000	5,000	14,000	14,000
Income (loss) before income taxes	(1,007,000)	(884,000)	(2,862,000)	(2,711,000)
Fixed asset additions	0	0	0	0
Segment assets	18,894,000		18,894,000		12,749,000
Goodwill	0		0		0
Other intangible assets	$ 0		$ 0		$ 0