Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Summary of Fair Value of Financial Assets by Level

The following tables summarize the amortized costs, unrealized gains and losses and fair value of these financial assets by significant investment category and their levels within the fair value hierarchy (in thousands):


	March 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Level I		Level II		Level III
Financial Assets:
Cash Equivalents:
Money market funds	$	379,345	$	—	$	—	$	379,345	$	379,345	$	—	$	—



Marketable Securities:
Commercial paper	46,658		—		—		46,658		—		46,658		—
Certificate of deposits(1)	80,069		—		—		80,069		—		80,069		—
U.S. government notes	661,366		190		(38)		661,518		661,518		—		—
Corporate bonds	972,063		709		(522)		972,250		—		972,250		—
Agency securities	423,551		287		(3)		423,835		—		423,835		—
	2,183,707		1,186		(563)		2,184,330		661,518		1,522,812		—
Other Assets:
Money market funds - restricted	4,236		—		—		4,236		4,236		—		—
Total Financial Assets	$	2,567,288	$	1,186	$	(563)	$	2,567,911	$	1,045,099	$	1,522,812	$	—


	December 31, 2020
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Level I		Level II		Level III
Financial Assets:
Cash Equivalents:
Money market funds	$	438,854	$	—	$	—	$	438,854	$	438,854	$	—	$	—


Marketable Securities:
Commercial paper	51,211		—		—		51,211		—		51,211		—
Certificate of deposits(1)	50,136		3		—		50,139		—		50,139		—
U.S. government notes	523,320		187		(1)		523,506		523,506		—		—
Corporate bonds	878,484		1,167		(330)		879,321		—		879,321		—
Agency securities	475,132		343		(3)		475,472		—		475,472		—
	1,978,283		1,700		(334)		1,979,649		523,506		1,456,143		—
Other Assets:
Money market funds - restricted	4,235		—		—		4,235		4,235		—		—
Total Financial Assets	$	2,421,372	$	1,700	$	(334)	$	2,422,738	$	966,595	$	1,456,143	$	—

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(1) As of March 31, 2021 and December 31, 2020, all of our certificates of deposits were domestic deposits.

Fair Value of Available-For-Sale Investments By Contractual Maturity

The fair values of available-for-sale marketable securities, by remaining contractual maturity, are as follows (in thousands):


	March 31, 2021
Due in 1 year or less	$	1,246,986
Due in 1 to 2 years	937,344
Total marketable securities	$	2,184,330