Product Warranty (Tables)

9 Months Ended

Sep. 30, 2013

Product Warranties Disclosures [Abstract]

Summary of product warranty activity

The following table summarizes product warranty activity during 2013 and 2012:

	Nine Months Ended
	September 30,
	2013			2012
Beginning balance	$	814		$	933
Charges to expense	746			574
Costs incurred	(550		)	(586		)
Ending balance	$	1,010		$	921