The following is a summary of available-for-sale marketable securities, excluding those securities classified within cash and cash equivalents on the consolidated balance sheets (in thousands):


	January 31, 2022
	Amortized Costs		Unrealized Gains		Unrealized Losses		Fair Value
U.S. treasury securities	$	223,950	$	23	$	(941)	$	223,032




Total marketable securities	$	223,950	$	23	$	(941)	$	223,032


	January 31, 2021
	Amortized Costs		Unrealized Gains		Unrealized Losses		Fair Value
U.S. treasury securities	$	268,141	$	29	$	(1)	$	268,169
Corporate notes and bonds	14,487		100		—		14,587


Certificates of deposit	280		—		—		280
Total marketable securities	$	282,908	$	129	$	(1)	$	283,036

As of January 31, 2022, the fair values of available-for-sale marketable securities, by remaining contractual maturity, were as follows (in thousands):


Due within one year	$	120,093
Due in one year through five years	102,939
Total	$	223,032

The Company's marketable securities consist primarily of U.S. treasury securities. The Company views its marketable securities as available to support its current operations, therefore these marketable securities have been classified as short-term available for sale securities.

During the years ended January 31, 2022, 2021 and 2020, there were no material gains or losses from the sale of available-for-sale marketable securities that were reclassified out of accumulated other comprehensive loss.

The Company regularly reviews the changes to the rating of its debt securities by rating agencies as well as reasonably monitors the surrounding economic conditions to assess the risk of expected credit losses. As of January 31, 2022, the unrealized losses and the related risk of expected credit losses were insignificant.