Marketable Securities

3 Months Ended

Mar. 31, 2021

Investments Debt And Equity Securities [Abstract]

2. Marketable Securities

The following table summarizes cash equivalents and marketable securities held at March 31, 2021 and December 31, 2020 (in thousands), which are recorded at fair value. The table below excludes $494.2 million and $395.1 million of cash at March 31, 2021 and December 31, 2020, respectively.

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
March 31, 2021
Cash equivalents:
Money market funds	$	629,357	$	—	$	—		$	629,357
Corporate debt securities		2,533		1		(2	)		2,532
Certificates of deposit		—		—		—			—
Commercial paper		—		—		—			—
Total cash equivalents		631,890		1		(2	)		631,889
Marketable securities:
U.S. Treasury securities		—		—		—			—
Corporate debt securities		536,144		37		(551	)		535,630
Certificates of deposit		54,273		—		—			54,273
Government-sponsored enterprise securities		3,120		—		(1	)		3,119
Commercial paper		87,120		2		—			87,122
Total marketable securities		680,657		39		(552	)		680,144
Total cash equivalents and marketable securities	$	1,312,547	$	40	$	(554	)	$	1,312,033
December 31, 2020
Cash equivalents:
Money market funds	$	742,958	$	—	$	—		$	742,958
Corporate debt securities		2,526		1		(24	)		2,503
Certificates of deposit		12,527		—		—			12,527
Commercial paper		15,549		—		—			15,549
Total cash equivalents		773,560		1		(24	)		773,537
Marketable securities:
U.S. Treasury securities		47,976		3		—			47,979
Corporate debt securities		324,569		43		(156	)		324,456
Certificates of deposit		25,162		—		—			25,162
Government-sponsored enterprise securities		33,738		5		(2	)		33,741
Commercial paper		90,375		—		—			90,375
Total marketable securities		521,820		51		(158	)		521,713
Total cash equivalents and marketable securities	$	1,295,380	$	52	$	(182	)	$	1,295,250

As of March 31, 2021 and December 31, 2020, the aggregate fair value of marketable securities that were in an unrealized loss position for less than twelve months was $473.7 million and $280.3 million, respectively. As of March 31, 2021 and December 31, 2020, no marketable securities were in an unrealized loss position for more than twelve months. The Company has recorded a net unrealized loss of $0.4 million during the three months ended March 31, 2021 related to its debt securities, which is included in comprehensive loss on the condensed consolidated statements of operations and comprehensive loss. No unrealized losses related to debt securities were recorded during the three months ended March 31, 2020.

The Company determined that there is no material credit risk associated with the above investments as of March 31, 2021. As such, an allowance for credit losses was not recognized. As of March 31, 2021, the Company does not intend to sell such securities and it is not more likely than not that the Company will be required to sell the securities before recovery of their amortized cost basis. No available-for-sale debt securities held as of March 31, 2021 had remaining maturities greater than two years.