Marketable Securities (Tables)

6 Months Ended

Jul. 31, 2021

Investments Debt And Equity Securities [Abstract]

Amortized Cost, Gross Unrealized Gains (Losses) and Fair Value of Available-For-Sale Securities

The amortized cost, gross unrealized gains (losses) and fair value of available-for-sale securities by major security type and class of security as of July 31, 2021, January 31, 2021 and July 31, 2020 were as follows:

	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		(Losses)			Value
As of July 31, 2021
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	122,173	$	14	$	(87	)	$	122,100
Corporate bonds		28,808		2		(24	)		28,786
Commercial paper		6,096		—		—			6,096
		157,077		16		(111	)		156,982
Long-term Investments:
Municipal and pre-refunded municipal bonds		40,069		34		(56	)	$	40,047
Corporate bonds		61,646		4		(159	)		61,491
Mutual funds, held in rabbi trust		11,610		143		(42	)		11,711
		113,325		181		(257	)		113,249
	$	270,402	$	197	$	(368	)	$	270,231
As of January 31, 2021
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	127,097	$	11	$	(53	)	$	127,055
Corporate bonds		38,695		1		(48	)		38,648
Commercial paper		8,992		—		—			8,992
		174,784		12		(101	)		174,695
Long-term Investments:
Municipal and pre-refunded municipal bonds		53,134		17		(46	)		53,105
Corporate bonds		59,890		3		(129	)		59,764
Mutual funds, held in rabbi trust		10,827		20		(54	)		10,793
		123,851		40		(229	)		123,662
	$	298,635	$	52	$	(330	)	$	298,357

	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		(Losses)		Value
As of July 31, 2020
Short-term Investments:
Municipal and pre-refunded municipal bonds	$	210	$	—	$	—	$	210
Corporate bonds		291		—		—		291
		501		—		—		501
Long-term Investments:
Municipal and pre-refunded municipal bonds		53		1		—		54
Corporate bonds		30		—		—		30
Mutual funds, held in rabbi trust		8,767		365		—		9,132
		8,850		366		—		9,216
	$	9,351	$	366	$	—	$	9,717