Other Accrued Liabilities (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Accrued warranty
Balance at beginning of period	$ 186,000	$ 467,000	$ 227,000	$ 510,000
Accruals for warranties issued during the period	55,000	160,000	80,000	285,000
Warranty claims	(101,000)	(219,000)	(167,000)	(387,000)
Balance at end of period	$ 140,000	$ 408,000	$ 140,000	$ 408,000