Revenue Concentrations, Significant Customers, and Geographic Areas (Summary Of Revenue By Product Line) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Concentration Risk [Line Items]
Revenues	$ 17,732	$ 16,429
High Precision 3D and 2D Sensors [Member]
Concentration Risk [Line Items]
Revenues	6,357	4,122
Inspection and Metrology Systems [Member]
Concentration Risk [Line Items]
Revenues	6,339	8,361
Semiconductor Sensors [Member]
Concentration Risk [Line Items]
Revenues	$ 5,036	$ 3,946