Basis of Presentation and General Information (Narrative) (Details) - USD ($)	3 Months Ended
	Apr. 02, 2021	Jan. 01, 2021	Jun. 26, 2020	Mar. 27, 2020	Dec. 27, 2019
Basis Of Presentation And General Information [Line Items]
Revenue recognized as a result of change in contract liability	$ 5,500,000			$ 4,400,000
Deferred commissions		$ 1,500,000			$ 1,600,000
Commissions expense	200,000			400,000
Impairment loss recognized to capitalization of deferred commission	$ 0			$ 0
ASU 2019-12 [Member]
Basis Of Presentation And General Information [Line Items]
Change in accounting principle, accounting standards update, adoption date	Dec. 15, 2020
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, immaterial effect	true
COVID-19 [Member]
Basis Of Presentation And General Information [Line Items]
Global workforce reduced, percentage			10.00%
Restructuring costs			$ 5,000,000.0
Asset impairment charges		$ 3,900,000
Minimum [Member]
Basis Of Presentation And General Information [Line Items]
Business relationship agreement period	6 months
Maximum [Member]
Basis Of Presentation And General Information [Line Items]
Business relationship agreement period	12 months
Customer contract period	12 months