Revenue Recognition (Narrative) (Details) - ASU No. 2014-9 [Member] - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
REVENUE RECOGNITION
Increase in revenue due to accounting standard update	$ 123,000	$ 232,000
Maximum period in which accounts receivable become due		90 days
Revenue from goods and services transferred to customers at a point in time	$ 15,400,000	$ 43,400,000
Revenue from goods and services transferred to customers at a point in time as percentage of entity's revenue	93.00%	93.00%
Revenue from goods and services transferred to customers over time	$ 1,200,000	$ 3,300,000
Revenue from goods and services transferred to customers over time as percentage of entity's revenue	7.00%	7.00%
Minimum [Member]
REVENUE RECOGNITION
Product Warranty, Period		1 year
Period over which unsatisfied performance obligations are expected to be recognized		1 year
Maximum [Member]
REVENUE RECOGNITION
Increase in revenue due to accounting standard update	$ 123,000	$ 232,000
Product Warranty, Period		3 years
Amounts reclassified from beginning contract liabilities to revenue	$ 39,000	$ 262,000
Period over which unsatisfied performance obligations are expected to be recognized		3 years
Amortization period of incremental costs of obtaining a contract		1 year
Period between when entity transfer a promised good or service to a customer and when the customer pays for that good or service		1 year
Period for the value of unsatisfied performance obligations which are not disclosed		1 year