Commitment and Contingencies (Tables)

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

Schedule of Product Warranty Liability

The following table provides the changes in our product warranties, which are included in accrued liabilities:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2018			2017			2018			2017
	(in thousands)
Warranty, beginning of period	$	534		$	589		$	472		$	639
Warranty costs accrued	210			54			444			114
Settlements of warranty claims	(162		)	(113		)	(334		)	(223		)
Warranty, end of period	$	582		$	530		$	582		$	530