Segment Information and Geographical Data (Geographic Revenue before Reimbursements) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2025	Jun. 28, 2024	Jun. 27, 2025	Jun. 28, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 78,899	$ 77,656	$ 156,764	$ 154,843
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	62,697	64,133	126,708	128,884
Europe (U.K., Germany, France, Switzerland and Spain) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	8,858	8,630	17,213	16,623
Other (Australia, Canada, India and Uruguay) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 7,344	$ 4,893	$ 12,843	$ 9,336