Segment, Geographic, Product and Significant Customer Information - Product Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Segment Reporting Information [Line Items]
Products	$ 146,945	$ 133,589	$ 107,402
Automated Systems [Member]
Segment Reporting Information [Line Items]
Products	102,386	108,768	82,924
Integrated Systems [Member]
Segment Reporting Information [Line Items]
Products	31,579	15,334	11,412
Materials Characterization Systems [Member]
Segment Reporting Information [Line Items]
Products	$ 12,980	$ 9,487	$ 13,066