Business Segments - Summary of company's operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 7,856	$ 8,147	$ 16,007	$ 16,191
Cost of goods sold, exclusive of depreciation and amortization	(5,534)	(5,698)	(11,991)	(11,619)
Selling, general and administrative	(1,272)	(1,230)	(2,573)	(2,494)
Interest expense	(14)	(15)	(27)	(30)
Depreciation and amortization	(169)	(166)	(340)	(331)
Other income, net	2	4	10	14
Income (loss) from continuing operations before income tax provision	869	1,042	1,086	1,731
come tax provision (benefit)	247	313	309	520
Net income from continuing operations	622	729	777	1,211
Discontinued Operations:
Loss from operations of a discontinued component, net of income tax benefit	(74)	(13)	(160)	(77)
Write-down of assets associated with a discontinued component, net of income tax benefit	(268)		(268)
Net income from discontinued operations	(342)	(13)	(428)	(77)
Net income	280	716	349	1,134
Capital expenditures	49	84	136	185
Advanced Technology Group
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	5,587	5,293	10,889	10,409
Cost of goods sold, exclusive of depreciation and amortization	(3,584)	3,577	(7,364)	(7,048)
Selling, general and administrative	(838)	768	(1,569)	(1,497)
Interest expense	(12)	12	(23)	(25)
Depreciation and amortization	(110)	107	(219)	(214)
Other income, net		1	4	8
Income (loss) from continuing operations before income tax provision	1,043	830	1,718	1,633
come tax provision (benefit)	297	250	489	491
Net income from continuing operations	746	580	1,229	1,142
Discontinued Operations:
Loss from operations of a discontinued component, net of income tax benefit
Write-down of assets associated with a discontinued component, net of income tax benefit
Net income from discontinued operations
Net income	746	580	1,229	1,142
Capital expenditures	43	53	93	81
Consumer Products Group
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	2,269	2,854	5,118	5,782
Cost of goods sold, exclusive of depreciation and amortization	(1,950)	(2,121)	(4,627)	(4,571)
Selling, general and administrative	(434)	(462)	(1,004)	(997)
Interest expense	(2)	(3)	(4)	(5)
Depreciation and amortization	(59)	(59)	(121)	(117)
Other income, net	2	3	6	6
Income (loss) from continuing operations before income tax provision	(174)	212	(632)	98
come tax provision (benefit)	(50)	63	(180)	29
Net income from continuing operations	(124)	149	(452)	69
Discontinued Operations:
Loss from operations of a discontinued component, net of income tax benefit	(74)	(13)	(160)	(77)
Write-down of assets associated with a discontinued component, net of income tax benefit	(268)		(268)
Net income from discontinued operations	(342)	(13)	(428)	(77)
Net income	(466)	136	(880)	(8)
Capital expenditures	$ 6	$ 31	$ 43	$ 104