Leases (Lease Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Leases [Abstract]
Operating lease cost		$ 2,656	$ 2,977	$ 8,007	$ 8,928
Short-term Lease, Cost	[1]	716	121	1,384	1,004
Total lease cost	[2]	$ 3,372	$ 3,098	$ 9,391	$ 9,932

[1] Includes variable lease cost, which was immaterial.

[2] Included in cost of revenue, sales and marketing, research and development and general and administration in the Company’s unaudited condensed statement of operations.