Marketable Securities (Tables)

3 Months Ended

Mar. 28, 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 March 28, 2021, and December 27, 2020:

	March 28, 2021
(In thousands)	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair Value
Short-term AFS securities
Corporate debt securities	$	125,933	$	417	$	(19)	$	126,331
Certificates of deposit	59,083		—		—		59,083
U.S. Treasury securities	51,225		27		(1)		51,251
U.S. governmental agency securities	39,362		42		—		39,404
Commercial paper	21,385		—		—		21,385
Total short-term AFS securities	$	296,988	$	486	$	(20)	$	297,454
Long-term AFS securities
Corporate debt securities	$	150,272	$	1,125	$	(119)	$	151,278
U.S. Treasury securities	101,222		1,751		(8)		102,965
U.S. governmental agency securities	51,588		15		(13)		51,590
Municipal securities	12,161		1		(7)		12,155
Total long-term AFS securities	$	315,243	$	2,892	$	(147)	$	317,988

	December 27, 2020
(In thousands)	Amortized Cost		Gross unrealized gains		Gross unrealized losses		Fair Value
Short-term AFS securities
Corporate debt securities	$	129,805	$	504	$	(8)	$	130,301
Certificates of deposit	36,525		—		—		36,525
U.S. Treasury securities	79,467		39		(3)		79,503
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 March 28, 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:

	March 28, 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
Corporate debt securities	$	50,264	$	(19)	$	—	$	—	$	50,264	$	(19)
U.S. Treasury securities	10,563		(1)		—		—		10,563		(1)
Total short-term AFS securities	$	60,827	$	(20)	$	—	$	—	$	60,827	$	(20)
Long-term AFS securities
Corporate debt securities	$	42,532	$	(119)	$	—	$	—	$	42,532	$	(119)
U.S. Treasury securities	9,493		(8)		—		—		9,493		(8)
U.S. governmental agency securities	21,235		(13)		—		—		21,235		(13)
Municipal securities	7,161		(7)		—		—		7,161		(7)
Total long-term AFS securities	$	80,421	$	(147)	$	—	$	—	$	80,421	$	(147)

	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
Corporate debt securities	$	33,735	$	(8)	$	—	$	—	$	33,735	$	(8)
U.S. Treasury securities	20,133		(3)		—		—		20,133		(3)
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)