Revenue and Geographic Information - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 25, 2021	Jun. 26, 2020
Change In Contract With Customer Liability [Roll Forward]
Deferred revenue – beginning of period	$ 30,466	$ 23,820
Amounts billed, but not recognized	13,271	12,911
Recognition of revenue	(13,592)	(11,008)
Deferred revenue acquired	1,469	0
Deferred revenue – end of period	$ 31,614	$ 25,723