Product Warranty - Change in Product Warranty Liability (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Beginning balance	$ 1,098
Cost of warranty claims	(345)
Accruals for product warranties	356
Total	$ 1,109
Minimum [Member]
Standard Product Warranty Period [Line Items]
Standard product warranty period	1 year
Maximum [Member]
Standard Product Warranty Period [Line Items]
Standard product warranty period	2 years