Short-Term Investments (Tables)

3 Months Ended

Apr. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Short-Term Investments

At April 30, 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	$	22,350	$	18	$	—	$	22,368
Asset-backed securities	144,412		470		(49)		144,833
Commercial paper	59,425		4		(5)		59,424
Corporate notes and bonds	535,609		1,743		(209)		537,143
Foreign government bonds	32,092		41		(9)		32,124
U.S. agency obligations	52,761		78		—		52,839
U.S. treasury securities	116,374		356		(8)		116,722
Total available-for-sale securities	$	963,023	$	2,710	$	(280)	$	965,453

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):

	April 30, 2021		January 31, 2021
Due in one year or less	$	356,853	$	428,155
Due in one to five years	608,600		504,967
Total	$	965,453	$	933,122

Schedule of Fair Values and Gross Unrealized Loss Position of Available-for-Sale Securities Aggregated by Investment Category

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 April 30, 2021 (in thousands):

	Held for less than 12 months
	Fair value	Gross unrealized losses
Asset-backed securities	30,844	(49)
Commercial paper	33,342	(5)
Corporate notes and bonds	174,182	(209)
Foreign government bonds	12,097	(9)
U.S. treasury securities	7,479	(8)

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)