Depreciation and Amortization (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 4,837	$ 4,597	$ 4,705
Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization	4,446	4,180	4,213
Operating Segments | Thin-film Equipment Segment
Segment Reporting Information [Line Items]
Depreciation and amortization	2,710	2,443	2,379
Operating Segments | Photonics
Segment Reporting Information [Line Items]
Depreciation and amortization	1,736	1,737	1,834
Unallocated Amount to Segment
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 391	$ 417	$ 492