Revenue - Primary Geography Markets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Disaggregation of Revenue [Line Items]
Total net revenues	$ 108,885	$ 95,114
Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	76,108	71,157
Products and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total net revenues	32,777	23,957
United States
Disaggregation of Revenue [Line Items]
Total net revenues	35,970	27,912
Asia
Disaggregation of Revenue [Line Items]
Total net revenues	72,372	65,329
Europe
Disaggregation of Revenue [Line Items]
Total net revenues	543	1,648
Rest of World
Disaggregation of Revenue [Line Items]
Total net revenues		225
TFE
Disaggregation of Revenue [Line Items]
Total net revenues	73,678	69,348
TFE | Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	73,678	69,348
TFE | United States
Disaggregation of Revenue [Line Items]
Total net revenues	1,306	4,050
TFE | Asia
Disaggregation of Revenue [Line Items]
Total net revenues	72,372	65,298
Photonics
Disaggregation of Revenue [Line Items]
Total net revenues	35,207	25,766
Photonics | Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	2,430	1,809
Photonics | Products and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total net revenues	32,777	23,957
Photonics | United States
Disaggregation of Revenue [Line Items]
Total net revenues	34,664	23,862
Photonics | Asia
Disaggregation of Revenue [Line Items]
Total net revenues		31
Photonics | Europe
Disaggregation of Revenue [Line Items]
Total net revenues	$ 543	1,648
Photonics | Rest of World
Disaggregation of Revenue [Line Items]
Total net revenues		$ 225