Revenue Concentrations, Significant Customers, and Geographic Areas (Summary Of Revenue By Product Line) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Concentration Risk [Line Items]
Revenues	$ 15,996	$ 15,044	$ 32,425	$ 30,020
High Precision 3D and 2D Sensors [Member]
Concentration Risk [Line Items]
Revenues	4,745	2,004	8,867	5,753
Inspection and Metrology Systems [Member]
Concentration Risk [Line Items]
Revenues	7,661	9,918	16,022	17,009
Semiconductor Sensors [Member]
Concentration Risk [Line Items]
Revenues	$ 3,590	$ 3,122	$ 7,536	$ 7,258