Product Warranties Schedule of Product Liability (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012	Mar. 31, 2011
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Product warranty accrual, at the beginning of the period			$ 983	$ 605	$ 776	$ 724
Warranty expenses accrued	34	435	645	1,142
Warranty settlements made	217	369	1,035	957
Product warranty accrual, at the end of period	$ 593	$ 790	$ 593	$ 790	$ 776	$ 724
Minimum
Product Warranty [Line Items]
Product Liability, Warranty Period			1 year
Maximum
Product Warranty [Line Items]
Product Liability, Warranty Period			3 years