Revenue Concentrations, Significant Customers, and Geographic Areas (Summary Of Revenue By Product Line) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Revenues	$ 18,063	$ 16,683	$ 15,854	$ 14,120	$ 13,176	$ 11,828	$ 16,409	$ 11,920	$ 64,720	$ 53,333
High Precision 3D and 2D Sensors [Member]
Product Information [Line Items]
Revenues									21,532	17,079
Semiconductor Sensors [Member]
Product Information [Line Items]
Revenues									13,606	11,059
Inspection and Metrology Systems [Member]
Product Information [Line Items]
Revenues									$ 29,582	$ 25,195