Other Accrued Liabilities (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Accrued warranty
Balance at beginning of period	$ 227,000	$ 510,000
Accruals for warranties issued during the period	141,000	470,000
Warranty claims	(251,000)	(753,000)
Balance at end of period	$ 117,000	$ 227,000