Marketable Securities (Tables)

9 Months Ended

Sep. 26, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost, Gross Unrealized Gains and Losses, and Fair Market Value of AFS Securities

The following tables present the amortized cost, gross unrealized gains and losses, and fair market value of our AFS securities as of September 26, 2021, and December 27, 2020:

	September 26, 2021
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Short-term AFS securities
U.S. Treasury securities	$	108,696	$	898	$	(2)	$	109,592
Certificates of deposit	109,253		—		—		109,253
Corporate debt securities	100,627		361		(14)		100,974
U.S. governmental agency securities	19,964		10		—		19,974
Commercial paper	18,021		—		—		18,021
Total short-term AFS securities	$	356,561	$	1,269	$	(16)	$	357,814
Long-term AFS securities
Corporate debt securities	$	233,971	$	594	$	(274)	$	234,291
U.S. Treasury securities	71,722		200		(61)		71,861
U.S. governmental agency securities	42,497		—		(43)		42,454
Municipal securities	12,123		5		(13)		12,115
Total long-term AFS securities	$	360,313	$	799	$	(391)	$	360,721

	December 27, 2020
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Short-term AFS securities
U.S. Treasury securities	$	79,467	$	39	$	(3)	$	79,503
Certificates of deposit	36,525		—		—		36,525
Corporate debt securities	129,805		504		(8)		130,301
U.S. governmental agency securities	25,113		61		(3)		25,171
Commercial paper	37,580		—		—		37,580
Total short-term AFS securities	$	308,490	$	604	$	(14)	$	309,080
Long-term AFS securities
Corporate debt securities	$	134,296	$	1,643	$	(5)	$	135,934
U.S. Treasury securities	95,511		2,054		—		97,565
U.S. governmental agency securities	48,342		19		(13)		48,348
Municipal securities	4,994		—		(10)		4,984
Total long-term AFS securities	$	283,143	$	3,716	$	(28)	$	286,831

Schedule of AFS Securities in Unrealized Loss Position

The following tables represent the AFS securities as of September 26, 2021, and December 27, 2020, that were in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by investment category and the length of time that individual securities have been in a continuous unrealized loss position:

	September 26, 2021
	Less than 12 Months				12 Months or Greater				Total
(In thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Short-term AFS securities
U.S. Treasury securities	$	32,611	$	(2)	$	—	$	—	$	32,611	$	(2)
Corporate debt securities	28,090		(14)		—		—		28,090		(14)
Total short-term AFS securities	$	60,701	$	(16)	$	—	$	—	$	60,701	$	(16)
Long-term AFS securities
Corporate debt securities	$	128,315	$	(274)	$	—	$	—	$	128,315	$	(274)
U.S. Treasury securities	54,539		(61)		—		—		54,539		(61)
U.S. governmental agency securities	42,454		(43)		—		—		42,454		(43)
Municipal securities	5,114		(13)		—		—		5,114		(13)
Total long-term AFS securities	$	230,422	$	(391)	$	—	$	—	$	230,422	$	(391)

	December 27, 2020
	Less than 12 Months				12 Months or Greater				Total
(In thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Short-term AFS securities
U.S. Treasury securities	$	20,133	$	(3)	$	—	$	—	$	20,133	$	(3)
Corporate debt securities	33,735		(8)		—		—		33,735		(8)
U.S. governmental agency securities	4,999		(2)		8,749		(1)		13,748		(3)
Total short-term AFS securities	$	58,867	$	(13)	$	8,749	$	(1)	$	67,616	$	(14)
Long-term AFS securities
Corporate debt securities	$	6,717	$	(5)	$	—	$	—	$	6,717	$	(5)
U.S. governmental agency securities	26,236		(13)		—		—		26,236		(13)
Municipal securities	4,984		(10)		—		—		4,984		(10)
Total long-term AFS securities	$	37,937	$	(28)	$	—	$	—	$	37,937	$	(28)