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 April 30, 2018 and January 31, 2018 were as follows (in thousands):



	As of April 30, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Estimated Fair Value

	(unaudited)
Cash equivalents:
Money market funds	$	145,932	$	—	$	—		$	145,932
Commercial paper	9,972		—		—			9,972
U.S. treasury securities	9,995		—		—			9,995
Corporate debt securities	6,996		—		(1		)	6,995
Total cash equivalents	$	172,895	$	—	$	(1	)	$	172,894
Short-term investments:
Commercial paper	$	43,639	$	—	$	—		$	43,639
U.S. treasury securities	251,000		—		(270		)	250,730
Corporate debt securities	40,972		1		(57		)	40,916
Total short-term investments	335,611		1		(327		)	335,285
Total	$	508,506	$	1	$	(328	)	$	508,179



	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 April 30, 2018 and January 31, 2018.

The following tables present the contractual maturities of the Company’s short-term investments as of April 30, 2018 and January 31, 2018 (in thousands):



	As of April 30, 2018				As of January 31, 2018
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value

	(unaudited)
Due within one year	$	306,045	$	305,761	$	93,421	$	93,237
Due between one to five years	29,566		29,524		8,546		8,528
	$	335,611	$	335,285	$	101,967	$	101,765

The Company had 55 and 23 short-term investments in unrealized loss positions as of April 30, 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 months ended April 30, 2018 or 2017.

For available-for-sale debt securities that have unrealized losses, the Company evaluates whether (i) it has the intention to sell any of these investments and (ii) whether it is not more likely than not that it 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 April 30, 2018 and January 31, 2018.