Product Warranty (Tables)

3 Months Ended

Mar. 31, 2018

Product Warranty

Schedule of product warranty liability

	Three months ended
	March 31,
	2018		2017
	(in thousands)
Balance at January 1 (beginning of year)	$	4,502	$	2,666
Warranties issued during the period		1,540		1,166
Settlements made during the period		(1,334)		(454)
Changes in estimate of liability for pre-existing warranties during the period		260		(254)
Balance at March 31 (end of period)	$	4,968	$	3,124
Amount classified as current	$	4,583	$	2,748
Amount classified as long-term		385		376
Total warranty liability	$	4,968	$	3,124