Purchased Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense of finite-lived intangibles	$ 854,000	$ 854,000	$ 936,000
Thin-film Equipment Segment
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	2,000,000
Photonics
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 217,000