Segment Information and Geographical Data (Geographic Revenue before Reimbursements) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2023	Sep. 30, 2022	Sep. 29, 2023	Sep. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 75,856	$ 72,033	$ 224,187	$ 223,625
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	63,955	62,505	190,578	193,614
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	7,399	5,311	21,132	17,952
Other (Australia, Canada, India and Uruguay) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 4,502	$ 4,217	$ 12,477	$ 12,059