Cash Equivalents and Marketable Securities

9 Months Ended

Sep. 30, 2021

Cash Equivalents And Marketable Securities [Abstract]

Cash Equivalents and Marketable Securities

We invest in certain U.S. government money market funds classified as cash equivalents. The marketable securities consist of high investment grade fixed income securities that are primarily invested in commercial paper, corporate bonds, and U.S. government securities.

Cash equivalents and marketable securities classified as available-for-sale consisted of the following:


	September 30, 2021
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash equivalents:
Money market funds	$	69,644	$	—	$	—		$	69,644
Short-term marketable securities:
U.S. treasury notes		60,526		29		—			60,555
Commercial paper		184,273		7		(3	)		184,277
Corporate debt securities		134,365		10		(24	)		134,351
Supranational debt securities		40,081		1		(1	)		40,081
Total short-term marketable securities		419,245		47		(28	)		419,264
Total cash equivalents and marketable securities	$	488,889	$	47	$	(28	)	$	488,908


	December 31, 2020
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash equivalents:
Money market funds	$	266,437	$	—	$	—		$	266,437
Short-term marketable securities:
U.S. treasury bills		14,996		3		—			14,999
U.S. treasury notes		45,292		100		(1	)		45,391
Commercial paper		144,851		—		—			144,851
Corporate debt securities		45,680		93		(3	)		45,770
Total short-term marketable securities		250,819		196		(4	)		251,011
Total cash equivalents and marketable securities	$	517,256	$	196	$	(4	)	$	517,448

There have been no significant realized gains or losses on available-for-sale securities for the periods presented. There were no available-for-sale securities that have been in a continuous unrealized loss position for more than 12 months. As of September 30, 2021, our short-term marketable securities have average contractual maturities of approximately seven months. We believe that we have the ability to realize the full value of all of these investments upon their respective maturities.