Revenue and Geographic Information - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 24, 2021	Sep. 25, 2020
Change In Contract With Customer Liability [Roll Forward]
Deferred revenue – beginning of period	$ 30,466	$ 23,820
Amounts billed, but not recognized	20,971	20,515
Recognition of revenue	(20,168)	(15,978)
Deferred revenue acquired	1,469	0
Deferred revenue – end of period	$ 32,738	$ 28,357