Segment and Geographic Information - Depreciation and Amortization (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 3,591	$ 4,614
Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization	3,219	4,257
Operating Segments \| TFE
Segment Reporting Information [Line Items]
Depreciation and amortization	1,909	2,387
Operating Segments \| Photonics
Segment Reporting Information [Line Items]
Depreciation and amortization	1,310	1,870
Unallocated Amount to Segment
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 372	$ 357

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Name:	us-gaap_DepreciationAndAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration