Revenue - Primary Geography Markets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Disaggregation of Revenue [Line Items]
Total net revenues	$ 18,840	$ 24,827
Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	8,392	19,506
Products and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total net revenues	10,448	5,321
United States
Disaggregation of Revenue [Line Items]
Total net revenues	11,375	5,877
Asia
Disaggregation of Revenue [Line Items]
Total net revenues	7,443	18,784
Europe
Disaggregation of Revenue [Line Items]
Total net revenues	22	166
TFE
Disaggregation of Revenue [Line Items]
Total net revenues	7,962	18,945
TFE | Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	7,962	18,945
TFE | United States
Disaggregation of Revenue [Line Items]
Total net revenues	519	161
TFE | Asia
Disaggregation of Revenue [Line Items]
Total net revenues	7,443	18,784
Photonics
Disaggregation of Revenue [Line Items]
Total net revenues	10,878	5,882
Photonics | Products Transferred at a Point in Time
Disaggregation of Revenue [Line Items]
Total net revenues	430	561
Photonics | Products and Services Transferred Over Time
Disaggregation of Revenue [Line Items]
Total net revenues	10,448	5,321
Photonics | United States
Disaggregation of Revenue [Line Items]
Total net revenues	10,856	5,716
Photonics | Asia
Disaggregation of Revenue [Line Items]
Total net revenues
Photonics | Europe
Disaggregation of Revenue [Line Items]
Total net revenues	$ 22	$ 166