Marketable Securities

3 Months Ended

Mar. 31, 2022

Note 4. Marketable securities

Marketable securities as of March 31, 2022 consisted of the following (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Marketable securities, current:
Corporate debt securities	$	220,349	$	—	$	(1,040	)	$	219,309
U.S. Treasury securities		16,043		—		(146	)		15,897
U.S. government debt securities		10,000		—		(36	)		9,964
Marketable securities, non-current:
Corporate debt securities		80,816		—		(1,387	)		79,429
U.S. government debt securities		41,970		—		(876	)		41,094
U.S. Treasury securities		10,120		—		(165	)		9,955
Total marketable securities, current and non-current	$	379,298	$	—	$	(3,650	)	$	375,648

Marketable securities as of December 31, 2021 consisted of the following (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Marketable securities, current:
Corporate debt securities	$	219,414	$	1	$	(250	)	$	219,165
U.S. government debt securities		5,006		—		—			5,006
U.S. Treasury securities		8,987		—		(3	)		8,984
Marketable securities, non-current:
Corporate debt securities		89,538		—		(403	)		89,135
U.S. government debt securities		32,982		—		(105	)		32,877
U.S. Treasury securities		20,203		—		(15	)		20,188
Total marketable securities, current	$	376,130	$	1	$	(776	)	$	375,355

Marketable securities classified as current have maturities of less than one year. Marketable securities classified as non-current are those that: (i) have a maturity of greater than one year, and (ii) we do not intend to liquidate within the next twelve months, although these funds are available for use and, therefore, are classified as available-for-sale. No available-for-sale debt securities held as of March 31, 2022 or December 31, 2021 had remaining maturities greater than five years.

Marketable securities in unrealized loss positions as of March 31, 2022 consisted of the following (in thousands, except number of securities):

	Number of Securities		Fair Value		Gross Unrealized Losses
Marketable securities in continuous unrealized loss position for less than 12 months:
Corporate debt securities		99	$	269,361	$	(2,322	)
U.S. government debt securities		11		51,058		(912	)
U.S. Treasury securities		6		25,852		(311	)
Marketable securities in continuous unrealized loss position for greater than 12 months:
Corporate debt securities		15		26,881		(105	)
Total marketable securities in unrealized loss position		131	$	373,152	$	(3,650	)

There were no individual securities that were in a significant unrealized loss position as of March 31, 2022, and, based on factors such as historical experience, market data, issuer-specific factors, and current economic conditions, the Company did not record an allowance for credit losses as of March 31, 2022 related to these securities. Further, given the lack of significant change in the credit risk, the Company does not consider these marketable securities to be impaired.

As of December 31, 2021, no marketable securities were in a continuous unrealized loss position for 12 months or longer.