Product Warranty (Tables)

12 Months Ended

Dec. 31, 2020

Product Warranty

Schedule of product warranty liability

	Year ended December 31,
	2020		2019		2018
	(in thousands)
Balance at January 1 (beginning of year)	$	3,244	$	5,091	$	4,502
Warranties issued during the period		5,005		3,615		5,421
Settlements made during the period		(4,270)		(5,548)		(5,903)
Changes in estimate of liability for pre-existing warranties during the period		633		86		1,071
Balance at December 31 (end of period)	$	4,612	$	3,244	$	5,091
Amount classified as current	$	4,280	$	2,759	$	4,819
Amount classified as long-term		332		485		272
Total warranty liability	$	4,612	$	3,244	$	5,091