Significant Customers, Geographic Areas, And Business Segments (Summary Of Revenue By Product Line) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Product Information [Line Items]
Revenues	$ 5,803	$ 11,558	$ 13,003	$ 11,280	$ 13,790	$ 17,088	$ 16,859	$ 13,350	$ 41,644	$ 61,087
OEM Alignment Sensors [Member]
Product Information [Line Items]
Revenues									13,187	20,844
Semiconductor Sensors [Member]
Product Information [Line Items]
Revenues									6,363	6,940
SMT Inspection Sensors [Member]
Product Information [Line Items]
Revenues									$ 22,094	$ 33,303