Short-Term Investments

6 Months Ended

Jul. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Short-Term Investments

2. Short-Term Investments

At July 31, 2019, 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	$	3,500	$	8	$	—		$	3,508
Asset-backed securities	82,825		178		(51		)	82,952
Commercial paper	12,265		8		—			12,273
Corporate notes and bonds	223,632		989		(79		)	224,542
Foreign government bonds	1,501		—		(3		)	1,498
U.S. agency obligations	3,000		—		—			3,000
U.S. treasury securities	276,655		326		(66		)	276,915
Total available-for-sale securities	$	603,378	$	1,509	$	(199	)	$	604,688

At January 31, 2019, 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	$	6,001	$	10	$	(1	)	$	6,010
Asset-backed securities	78,682		13		(300		)	78,395
Commercial paper	9,118		1		(2		)	9,117
Corporate notes and bonds	185,409		178		(457		)	185,130
Foreign government bonds	1,502		—		(11		)	1,491
U.S. agency obligations	15,912		2		(2		)	15,912
U.S. treasury securities	243,119		78		(62		)	243,135
Total available-for-sale securities	$	539,743	$	282	$	(835	)	$	539,190

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):

	July 31, 2019		January 31, 2019
Due in one year or less	$	366,791	$	377,858
Due in greater than one year	237,897		161,332
Total	$	604,688	$	539,190

We have certain available-for-sale securities in a gross unrealized loss position, some of which have been in that position for more than 12 months. We review our debt securities classified as short-term investments on a regular basis to evaluate whether or not any security has experienced an other-than-temporary decline in fair value. We consider factors such as the length of time and extent to which the market value has been less than the cost, our financial position and near-term prospects and our intent to sell, or whether it is more likely than not we will be required to sell the investment before recovery of the investment’s amortized-cost basis. If we determine that an other-than-temporary decline exists in one of these securities, we would write down the respective investment to fair value. For debt securities, the portion of the write-down related to credit loss would be recognized as other income, net in our condensed consolidated statements of comprehensive income. Any portion not related to credit loss would be included in accumulated other comprehensive income. There were no impairments considered other-than-temporary as of July 31, 2019 and January 31, 2019.

The following table shows the fair values of these available-for-sale securities that have been in a gross unrealized loss position for more than 12 months, aggregated by investment category as of July 31, 2019 (in thousands):

	Fair value		Gross unrealized losses
Asset-backed securities	$	28,876	$	(51	)
Corporate notes and bonds	48,744		(79		)
Foreign government bonds	1,498		(3		)
U.S. treasury securities	91,766		(66		)

The following table shows the fair values of these available-for-sale securities that have been in a gross unrealized loss position for more than 12 months, aggregated by investment category as of January 31, 2019 (in thousands):

	Fair value		Gross unrealized losses
Certificates of deposits	$	999	$	(1	)
Asset-backed securities	69,131		(300		)
Commercial paper	7,155		(2		)
Corporate notes and bonds	121,006		(457		)
Foreign government bonds	1,490		(11		)
U.S. agency obligations	14,928		(2		)
U.S. treasury securities	130,785		(62		)