Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

The following is a summary of available-for-sale marketable securities held as of March 31, 2021 and December 31, 2020 (in thousands):


			Gross Unrealized						Classification on Balance Sheet
	Amortized Cost		Gains		Losses		Aggregate Fair Value		Short-Term Marketable Securities		Long-Term Marketable Securities
As of March 31, 2021

Commercial paper	$	51,962	$	8	$	(2)	$	51,968	$	51,968	$	—
Corporate bonds	1,525,643		6,535		(953)		1,531,225		677,111		854,114
U.S. government agency obligations	392,396		185		(106)		392,475		101,745		290,730
	$	1,970,001	$	6,728	$	(1,061)	$	1,975,668	$	830,824	$	1,144,844

As of December 31, 2020
Commercial paper	$	46,931	$	13	$	(8)	$	46,936	$	46,936	$	—
Corporate bonds	1,628,462		9,482		(262)		1,637,682		607,403		1,030,279
Municipal securities	3,495		—		(6)		3,489		—		3,489
U.S. government agency obligations	435,653		329		(63)		435,919		89,951		345,968
	$	2,114,541	$	9,824	$	(339)	$	2,124,026	$	744,290	$	1,379,736

Schedule of Fair Value Measurement

The following table details the fair value measurements within the fair value hierarchy of the Company’s financial assets as of March 31, 2021 and December 31, 2020 (in thousands):


	Total Fair Value		Fair Value Measurements at Reporting Date Using
			Level 1		Level 2
As of March 31, 2021
Cash Equivalents and Marketable Securities:
Money market funds	$	92,107	$	92,107	$	—

Commercial paper	51,968		—		51,968
Corporate bonds	1,531,225		—		1,531,225
U.S. government agency obligations	392,475		—		392,475
Mutual funds	21,165		21,165		—
	$	2,088,940	$	113,272	$	1,975,668




As of December 31, 2020
Cash Equivalents and Marketable Securities:
Money market funds	$	74,417	$	74,417	$	—
Commercial paper	75,785		—		75,785
Corporate bonds	1,637,682		—		1,637,682
Municipal securities	3,489		—		3,489
U.S. government agency obligations	435,919		—		435,919
Mutual funds	19,932		19,932		—
	$	2,247,224	$	94,349	$	2,152,875

Schedule of Contractual Maturities of Marketable Securities and Other Investment Related Assets

Contractual maturities of the Company’s available-for-sale marketable securities held as of March 31, 2021 and December 31, 2020 were as follows (in thousands):


	March 31, 2021		December 31, 2020
Due in 1 year or less	$	830,824	$	744,290
Due after 1 year through 5 years	1,144,844		1,379,736
	$	1,975,668	$	2,124,026