Product Warranty (Tables)

6 Months Ended

Jun. 30, 2018

Product Warranty

Schedule of product warranty liability

	Six months ended
	June 30,
	2018		2017
	(in thousands)
Balance at January 1 (beginning of year)	$	4,502	$	2,666
Warranties issued during the period		3,124		2,577
Settlements made during the period		(2,892)		(1,090)
Changes in estimate of liability for pre-existing warranties during the period		411		(281)
Balance at June 30 (end of period)	$	5,145	$	3,872
Amount classified as current	$	4,698	$	3,537
Amount classified as long-term		447		335
Total warranty liability	$	5,145	$	3,872