Marketable Securities - Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 26, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	$ 32,450	$ 14,166
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	19	6
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0	0
Municipal notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	8,641	14,166
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	4	6
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0	$ 0
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	0
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	0
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0
Certificates of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	0
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	0
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	8,862
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	3
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	0
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
In Unrealized Loss Position For Less Than 12 Months, Fair Value	14,947
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses	12
In Unrealized Loss Position For Greater Than 12 Months, Fair Value	0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses	$ 0