Short-Term Investments

9 Months Ended

Oct. 31, 2016

Investments Debt And Equity Securities [Abstract]

Short-Term Investments

Note 3. Short-Term Investments

At October 31, 2016, short-term investments consisted of the following (in thousands):

			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Available-for-sale securities:
Asset-backed securities	$	22,839	$	15	$	(6	)	$	22,848
Commercial paper		22,888		7		(10	)		22,885
Corporate notes and bonds		87,348		32		(73	)		87,307
U.S. agency obligations		88,906		40		(15	)		88,931
U.S. treasury securities		82,794		10		(44	)		82,760
Total available-for-sale securities	$	304,775	$	104	$	(148	)	$	304,731

At January 31, 2016, short-term investments consisted of the following (in thousands):  

			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Available-for-sale securities:
Asset-backed securities	$	5,456	$	—	$	(2	)	$	5,454
Commercial paper		5,970		—		—			5,970
Corporate notes and bonds		38,341		26		(40	)		38,327
U.S. agency obligations		124,626		14		(54	)		124,586
U.S. treasury securities		39,720		4		(37	)		39,687
Total available-for-sale securities	$	214,113	$	44	$	(133	)	$	214,024

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,		January 31,
	2016		2016
Due in one year or less	$	198,245	$	151,214
Due in greater than one year		106,486		62,810
Total	$	304,731	$	214,024

We have certain available-for-sale securities in a gross unrealized loss position, all of which have been in such position for less 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, the financial position and near-term prospects of the issuer 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, the respective investment would be written down to fair value. For debt securities, the portion of the write-down related to credit loss would be recognized to 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 (loss). There were no impairments considered other-than-temporary as of October 31, 2016 and January 31, 2016.

The following table shows the fair values and the gross unrealized losses of these available-for-sale securities aggregated by investment category as of October 31, 2016 (in thousands):  

			Gross
	Fair		Unrealized
	Value		Losses
Asset-backed securities	$	12,108	$	(6	)
Commercial paper		10,517		(10	)
Corporate notes and bonds		60,122		(73	)
U.S. agency obligations		20,493		(15	)
U.S. treasury securities		61,156		(44	)

The following table shows the fair values and the gross unrealized losses of these available-for-sale securities aggregated by investment category as of January 31, 2016 (in thousands):

			Gross
	Fair		Unrealized
	Value		Losses
Asset-backed securities	$	2,249	$	(2	)
Corporate notes and bonds		14,296		(40	)
U.S. agency obligations		82,806		(54	)
U.S. treasury securities		33,486		(37	)