Segment Information (Details) (USD $)	3 Months Ended		6 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013
Segment Reporting Information [Line Items]
Sales to external customers	$ 21,744,000	$ 14,410,000	$ 37,952,000	$ 28,678,000
Intersegment sales	0	0	0	0
Depreciation and amortization	403,000	428,000	803,000	851,000
Income (loss) before income taxes	5,318,000	2,504,000	8,846,000	5,125,000
Fixed asset additions	672,000	48,000	853,000	454,000
Segment assets	89,014,000		89,014,000		83,086,000
Goodwill	17,227,000		17,227,000		17,227,000
Other intangible assets	6,578,000		6,578,000		6,967,000
Seismic Energy Sources [Member]
Segment Reporting Information [Line Items]
Sales to external customers	7,883,000	7,169,000	14,161,000	12,576,000
Intersegment sales	347,000	0	727,000	0
Depreciation and amortization	69,000	50,000	138,000	101,000
Income (loss) before income taxes	2,978,000	1,788,000	4,257,000	2,547,000
Fixed asset additions	19,000	18,000	116,000	54,000
Segment assets	21,545,000		21,545,000		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	4,448,000	3,764,000	9,594,000	8,119,000
Intersegment sales	77,000	109,000	254,000	158,000
Depreciation and amortization	76,000	75,000	151,000	145,000
Income (loss) before income taxes	1,613,000	1,239,000	3,742,000	3,060,000
Fixed asset additions	575,000	32,000	604,000	363,000
Segment assets	17,793,000		17,793,000		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	1,384,000	711,000	3,046,000	1,593,000
Intersegment sales	250,000	134,000	541,000	263,000
Depreciation and amortization	19,000	70,000	36,000	139,000
Income (loss) before income taxes	701,000	191,000	1,572,000	562,000
Fixed asset additions	29,000	2,000	80,000	2,000
Segment assets	6,613,000		6,613,000		5,716,000
Goodwill	3,278,000		3,278,000		3,278,000
Other intangible assets	311,000		311,000		325,000
Underwater Robotic Vehicles [Member]
Segment Reporting Information [Line Items]
Sales to external customers	8,029,000	2,766,000	11,151,000	6,390,000
Intersegment sales	0	0	0	0
Depreciation and amortization	234,000	229,000	468,000	457,000
Income (loss) before income taxes	910,000	89,000	1,130,000	783,000
Fixed asset additions	49,000	(4,000)	53,000	35,000
Segment assets	25,000,000		25,000,000		22,724,000
Goodwill	6,270,000		6,270,000		6,270,000
Other intangible assets	6,150,000		6,150,000		6,542,000
Corporate Headquarters and Eliminations [Member]
Segment Reporting Information [Line Items]
Sales to external customers	0	0	0	0
Intersegment sales	(674,000)	(243,000)	(1,522,000)	(394,000)
Depreciation and amortization	5,000	4,000	10,000	9,000
Income (loss) before income taxes	(884,000)	(803,000)	(1,855,000)	(1,827,000)
Fixed asset additions	0	0	0	0
Segment assets	18,063,000		18,063,000		12,749,000
Goodwill	0		0		0
Other intangible assets	$ 0		$ 0		$ 0