Marketable Securities (Tables)

12 Months Ended

Jan. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities

As of January 31, 2021 and 2020, our marketable securities consisted of the following: 

	As of January 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
Commercial paper	$	26,222	$	—	$	—	$	26,222
Agency bonds	461,335		79		(49)		461,365
Corporate and other debt securities	465,207		1,113		(64)		466,256
U.S. government agency securities	834,894		28		(257)		834,665
Treasury bills	215,902		6		(6)		215,902
Marketable securities	$	2,003,560	$	1,226	$	(376)	$	2,004,410

	As of January 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
Commercial paper	$	37,894	$	—	$	—	$	37,894
Agency bonds	141,157		49		(43)		141,163
Corporate and other debt securities	320,407		775		(16)		321,166
U.S. government agency securities	71,794		45		(2)		71,837
Marketable securities	$	571,252	$	869	$	(61)	$	572,060

Summary of Contractual Maturities of Marketable Securities

The following table presents the contractual maturities of our marketable securities as of January 31, 2021 and 2020:

	As of January 31,
	2021		2020
	(in thousands)
Less than one year	$	1,017,048	$	315,900
Due in one to five years	987,362		256,160
Total	$	2,004,410	$	572,060