Segment Information - Financial information concerning the company's reportable segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Corporate and other (expenses) income:
Product revenue	$ 2,311	$ 1,083	$ 6,778	$ 3,653
Unfunded research and product development expenses (income)	301	327	948	1,037
Selling, general and administrative expenses	880	1,308	2,626	3,378
Segment profit (loss) from operations before income taxes and non-controlling interest	259	(1,179)	566	(2,524)
Segment profit (loss)	164	(1,149)	350	(2,540)	(2,086)
Total assets	4,634	4,214	4,634	4,214	4,845
Capital expenditures	26	2	68	12
Depreciation	22	29	68	102
Test and Measurement Instrumentation
Corporate and other (expenses) income:
Product revenue	2,311	1,083	6,778	3,653
Unfunded research and product development expenses (income)	301	327	948	1,038
Selling, general and administrative expenses	572	472	1,582	1,423
Segment profit (loss) from operations before income taxes and non-controlling interest	438	(668)	1,191	(1,491)
Segment profit (loss)	438	(668)	1,191	(1,491)
Total assets	2,191	2,039	2,191	2,039
Capital expenditures	2	2	44	12
Depreciation	21	23	62	73
New Energy
Corporate and other (expenses) income:
Unfunded research and product development expenses (income)				(1)
Selling, general and administrative expenses	25	41	67	137
Segment profit (loss) from operations before income taxes and non-controlling interest	(33)	(68)	(99)	20
Segment profit (loss)	(34)	(69)	(99)	19
Total assets	38	159	38	159
Depreciation		6	4	29
Other
Corporate and other (expenses) income:
Selling, general and administrative expenses	283	795	977	1,818
Segment profit (loss) from operations before income taxes and non-controlling interest	(146)	(443)	(526)	(1,053)
Segment profit (loss)	(258)	(448)	(794)	(1,058)
Total assets	2,405	2,016	2,405	2,016
Capital expenditures	24		24
Depreciation	1		2
Reconciling Items
Corporate and other (expenses) income:
Segment profit (loss)	$ 18	$ 36	$ 52	$ (10)