Other Accrued Liabilities (Details 1) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accrued warranty
Balance at beginning of period	$ 117,000	$ 227,000
Accruals for warranties issued during the period	10,000	25,000
Warranty claims	(34,000)	(66,000)
Balance at end of period	$ 93,000	$ 186,000