Short-Term Investments

9 Months Ended

Oct. 31, 2021

Investments, Debt and Equity Securities [Abstract]

At October 31, 2021, short-term investments consisted of the following (in thousands):


	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Available-for-sale securities:
Certificates of deposits	$	16,750	$	10	$	—	$	16,760
Asset-backed securities	190,558		152		(458)		190,252
Commercial paper	47,375		8		—		47,383
Corporate notes and bonds	642,377		809		(1,609)		641,577
Foreign government bonds	26,625		23		(57)		26,591
U.S. agency obligations	27,974		14		(50)		27,938
U.S. treasury securities	251,320		117		(397)		251,040
Total available-for-sale securities	$	1,202,979	$	1,133	$	(2,571)	$	1,201,541

At January 31, 2021, short-term investments consisted of the following (in thousands):


	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Available-for-sale securities:
Certificates of deposits	$	17,350	$	15	$	(1)	$	17,364
Asset-backed securities	125,833		745		(2)		126,576
Commercial paper	57,390		8		(2)		57,396
Corporate notes and bonds	428,710		2,360		(23)		431,047
Foreign government bonds	31,855		45		(2)		31,898
U.S. agency obligations	52,756		119		—		52,875
U.S. treasury securities	215,379		587		—		215,966
Total available-for-sale securities	$	929,273	$	3,879	$	(30)	$	933,122

The following table summarizes the estimated fair value of our short-term investments, designated as available-for-sale and classified by the contractual maturity date of the securities as of the dates shown (in thousands):


	October 31, 2021		January 31, 2021
Due in one year or less	$	378,075	$	428,155
Due in one to five years	823,466		504,967
Total	$	1,201,541	$	933,122

We have not recorded an allowance for credit losses, as we believe any such losses would be immaterial based on the high credit quality of our investments. We intend to hold our securities to maturity and it is more likely than not we will hold these securities until recovery of the cost basis.

The following table shows the fair values of available-for-sale securities which were in an unrealized loss position, aggregated by investment category, as of October 31, 2021 (in thousands):


	Held for less than 12 months
	Fair value	Gross unrealized losses

Asset-backed securities	132,390	(458)
Commercial paper	5,809	—
Corporate notes and bonds	448,241	(1,609)
Foreign government bonds	16,687	(57)
U.S. agency obligations	24,924	(50)
U.S. treasury securities	207,733	(397)

The following table shows the fair values of available-for-sale securities which were in an unrealized loss position, aggregated by investment category, as of January 31, 2021 (in thousands):


	Held for less than 12 months
	Fair value		Gross unrealized losses

Certificates of deposits	$	3,749	$	(2)
Asset-backed securities	3,318		(1)
Commercial paper	17,626		(2)
Corporate notes and bonds	29,558		(23)
Foreign government bonds	2,679		(2)

Asset values and gross unrealized losses of available-for-sale securities held for more than 12 months as of October 31, 2021 and January 31, 2021 were immaterial. There was no allowance for credit losses recorded as of October 31, 2021 and January 31, 2021