Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Schedule of Product Warranty Liability [Table Text Block]

The following is a summary of the change in the Company's accrued warranty reserve (in thousands):

	Three Months Ended
	March 31,
	2018			2017
Warranty liability balance, beginning of the period	$	1,124		$	1,821
Product warranty accruals (reversals)	(58		)	223
Utilization of accrual	(158		)	(315		)
Warranty liability balance, end of the period	$	908		$	1,729