Segment, Geographic, Product and Significant Customer Information (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Segment Reporting Information [Line Items]
Total product revenues	$ 143,827	$ 194,774	$ 154,548
Automated Systems [Member]
Segment Reporting Information [Line Items]
Total product revenues	119,451	139,261	110,955
Integrated Systems [Member]
Segment Reporting Information [Line Items]
Total product revenues	12,379	25,413	17,437
Materials Characterization Systems [Member]
Segment Reporting Information [Line Items]
Total product revenues	$ 11,997	$ 30,100	$ 26,156