Business Segments - Revenue Information by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2021	Mar. 28, 2020
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 11,959	$ 9,021
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	5,564	4,441
Europe
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	2,417	1,984
Rest of Americas
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	804	403
Asia/Pacific Rim
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 3,174	$ 2,193