Product Warranty (Tables)

9 Months Ended

Sep. 30, 2018

Product Warranties Disclosures [Abstract]

Summary of product warranty activity

The following table summarizes product warranty activity during 2018 and 2017:

	Nine Months Ended
	September 30,
	2018			2017
Beginning balance	$	2,074		$	2,280
Charges to expense	1,592			845
Costs incurred	(1,634		)	(810		)
Ending balance	$	2,032		$	2,315