Capital Additions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Capital additions	$ 4,356	$ 3,373	$ 3,117
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Capital additions	3,780	3,163	2,182
Operating Segments | Thin-film Equipment Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Capital additions	2,137	700	1,433
Operating Segments | Photonics
Segment Reporting, Asset Reconciling Item [Line Items]
Capital additions	1,643	2,463	749
Unallocated Amount to Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Capital additions	$ 576	$ 210	$ 935