Assets for Each Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014	Dec. 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and investments	$ 75,033	$ 81,414
Deferred income taxes	9,768	9,605
Other current assets	1,009	982
Common property, plant and equipment	1,309	1,302
Other assets	370	425
Consolidated total assets	140,560	148,276
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	53,071	54,548
Operating Segments | Equipment
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	31,309	33,428
Operating Segments | Photonics
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated total assets	$ 21,762	$ 21,120