Cash Equivalents and Short-Term Investments

The amortized cost, unrealized gain (loss) and estimated fair value of the Company’s cash equivalents and short-term investments as of July 31, 2018 and January 31, 2018 were as follows (in thousands):



	As of July 31, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value

	(unaudited)
Cash equivalents:
Money market funds	$	155,347	$	—	$	—		$	155,347
Commercial paper	12,237		—		—			12,237
Total cash equivalents	$	167,584	$	—	$	—		$	167,584
Short-term investments:
Commercial paper	$	56,191	$	—	$	—		$	56,191
U.S. treasury securities	248,081		—		(217		)	247,864
Corporate debt securities	39,352		6		(39		)	39,319
Total short-term investments	343,624		6		(256		)	343,374
Total	$	511,208	$	6	$	(256	)	$	510,958



	As of January 31, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value
Cash equivalents:
Money market funds	$	90,770	$	—	$	—		$	90,770
Total cash equivalents	$	90,770	$	—	$	—		$	90,770
Short-term investments:
Commercial paper	$	15,946	$	—	$	—		$	15,946
U.S. treasury securities	61,896		—		(158		)	61,738
Corporate debt securities	24,125		—		(44		)	24,081
Total short-term investments	101,967		—		(202		)	101,765
Total	$	192,737	$	—	$	(202	)	$	192,535

All short-term investments were designated as available-for-sale securities as of July 31, 2018 and January 31, 2018.

The following tables present the contractual maturities of the Company’s short-term investments as of July 31, 2018 and January 31, 2018 (in thousands):



	As of July 31, 2018				As of January 31, 2018
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value

	(unaudited)
Due within one year	$	328,694	$	328,460	$	93,421	$	93,237
Due between one to five years	14,930		14,914		8,546		8,528
	$	343,624	$	343,374	$	101,967	$	101,765

The Company had 53 and 23 short-term investments in unrealized loss positions as of July 31, 2018 and January 31, 2018, respectively. There were no material gross unrealized gains or losses from available-for-sale securities and no realized gains or losses from available-for-sale securities that were reclassified out of accumulated other comprehensive income for the three and six months ended July 31, 2018 or 2017.

For available-for-sale debt securities that have unrealized losses, the Company evaluates whether (i) the Company has the intention to sell any of these investments and (ii) it is not more likely than not that the Company will be required to sell any of these available-for-sale debt securities before recovery of the entire amortized cost basis. Based on this evaluation, the Company determined that there were no other-than-temporary impairments associated with short-term investments as of July 31, 2018 and January 31, 2018.