Revenue Concentrations, Significant Customers, and Geographic Areas (Narrative) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($) customer	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) customer	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) customer	Dec. 31, 2018 USD ($) customer
Revenue, Major Customer [Line Items]
Revenues	$ 16,852	$ 12,391	$ 15,044	$ 14,976	$ 18,063	$ 16,683	$ 15,854	$ 14,120	$ 59,263	$ 64,720
Accounts receivable	$ 16,059				$ 15,859				16,059	15,859
MRS based sensors [Member]
Revenue, Major Customer [Line Items]
Revenues									6,000	7,900
MRS based systems [Member]
Revenue, Major Customer [Line Items]
Revenues									$ 17,900	$ 13,300
Customer Concentration Risk [Member] | Revenues [Member]
Revenue, Major Customer [Line Items]
Number of customers | customer	0				2				0	2
Customer Concentration Risk [Member] | Revenues [Member] | Significant Customer B [Member]
Revenue, Major Customer [Line Items]
Percentage of Revenues										10.00%
Customer Concentration Risk [Member] | Export Revenues [Member]
Revenue, Major Customer [Line Items]
Percentage of Revenues									76.00%	72.00%
Customer Concentration Risk [Member] | Export Revenues [Member] | Significant Customer A [Member]
Revenue, Major Customer [Line Items]
Percentage of Revenues									10.00%	10.00%