Product Warranty (Tables)

12 Months Ended

Dec. 31, 2016

Product Warranty

Schedule of product warranty liability

	Year ended December 31,
	2016		2015		2014
	(in thousands)
Balance at January 1 (beginning of year)	$	3,555	$	1,526	$	1,428
Warranties issued during the period		3,125		4,305		1,743
Settlements made during the period		(4,249)		(2,672)		(2,096)
Changes in estimate of liability for pre-existing warranties during the period		235		396		451
Balance at December 31 (end of period)	$	2,666	$	3,555	$	1,526
Amount classified as current	$	2,426	$	3,363	$	1,352
Amount classified as long-term		240		192		174
Total warranty liability	$	2,666	$	3,555	$	1,526