Revenue Concentrations, Significant Customers, and Geographic Areas (Summary Of Revenue By Product Line) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Concentration Risk [Line Items]
Revenues	$ 14,120	$ 11,920
High Precision 3D and 2D Sensors [Member]
Concentration Risk [Line Items]
Revenues	5,055	3,904
Semiconductor Sensors [Member]
Concentration Risk [Line Items]
Revenues	3,161	2,317
SMT Inspection Systems, Metrology Products and Services [Member]
Concentration Risk [Line Items]
Revenues	$ 5,904	$ 5,699

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration