Cash, Cash Equivalents, and Investments (Tables)

9 Months Ended

Sep. 27, 2020

Cash and Cash Equivalents [Abstract]

Components of Cash, Cash Equivalents, and Investments

Cash, cash equivalents, and investments consisted of the following (in thousands):

	September 27, 2020		December 31, 2019
Cash	$	294,430	$	155,498
Money market instruments	3,926		15,933
Cash and cash equivalents	298,356		171,431
Corporate bonds	43,436		65,624
Asset-backed securities	34,536		66,680
Sovereign bonds	16,086		6,294
Municipal bonds	1,307		4,630
Treasury bills	—		92,914
Certificate of deposit	—		4,328
Current investments	95,365		240,470
Treasury bills	270,091		216,334
Corporate bonds	216,451		146,474
Asset-backed securities	95,007		46,403
Agency bonds	28,274		5,914
Sovereign bonds	8,410		16,005
Municipal bonds	1,110		2,322
Non-current investments	619,343		433,452
	$	1,013,064	$	845,353

Summary of Available-for-Sale Investments

The following table summarizes the Company’s available-for-sale investments as of September 27, 2020 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Current:
Corporate bonds	$	43,208	$	254	$	(26)	$	43,436
Asset-backed securities	34,277		259		—		34,536
Sovereign bonds	15,978		108		—		16,086
Municipal bonds	1,298		9		—		1,307
Non-current:
Treasury bills	268,071		2,030		(10)		270,091
Corporate bonds	213,850		2,717		(116)		216,451
Asset-backed securities	94,270		737		—		95,007
Agency bonds	28,193		81		—		28,274
Sovereign bonds	8,349		61		—		8,410
Municipal bonds	1,105		5		—		1,110
	$	708,599	$	6,261	$	(152)	$	714,708

Gross Unrealized Losses and Fair Values for Available-for-Sale Investments

The following table summarizes the Company’s gross unrealized losses and fair values for available-for-sale investments in an unrealized loss position as of September 27, 2020 (in thousands):

	Unrealized Loss Position For:
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate bonds	$	42,058	$	(142)	$	—	$	—	$	42,058	$	(142)
Treasury bills	11,543		(10)		—		—		11,543		(10)
	$	53,601	$	(152)	$	—	$	—	$	53,601	$	(152)

Schedule of Allowance for Credit Loss Activity

The following table summarizes the allowance for credit losses activity for the nine-month period ended September 27, 2020 (in thousands):

Balance as of December 31, 2019	$	—
Increases to the allowance for credit losses	160
Decreases to the allowance for credit losses	(85)
Write-offs	—
Balance as of September 27, 2020	$	75

Effective Maturity Dates of Available-for-Sale Investments

The following table presents the effective maturity dates of the Company’s available-for-sale investments as of September 27, 2020 (in thousands):

	<1 year		1-2 Years		2-3 Years		3-4 Years		4-5 Years		Total
Treasury bills	$	—	$	167,677	$	98,353	$	4,061	$	—	$	270,091
Corporate bonds	43,436		86,619		126,966		2,866		—		259,887
Asset-backed securities	34,536		45,513		45,457		52		3,985		129,543
Agency bonds	—		5,933		22,341		—		—		28,274
Sovereign bonds	16,086		4,973		3,437		—		—		24,496
Municipal bonds	1,307		1,110		—		—		—		2,417
	$	95,365	$	311,825	$	296,554	$	6,979	$	3,985	$	714,708