Fair Value Measurements (Tables)

3 Months Ended

Apr. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following table presents information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis using the above input categories (in thousands):

	As of April 30, 2018
	Level 1		Level 2		Level 3		Total
	(unaudited)
Assets:
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	—		6,995		—		6,995
Total cash equivalents	$	145,932	$	26,962	$	—	$	172,894
Short-term investments:
Commercial paper	$	—	$	43,639	$	—	$	43,639
U.S. treasury securities	—		250,730		—		250,730
Corporate debt securities	—		40,916		—		40,916
Total short-term investments	—		335,285		—		335,285
Total cash equivalents and short-term investments	$	145,932	$	362,247	$	—	$	508,179

	As of January 31, 2018
	Level 1		Level 2		Level 3		Total
Assets:
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	—		61,738		—		61,738
Corporate debt securities	—		24,081		—		24,081
Total short-term investments	—		101,765		—		101,765
Total cash equivalents and short-term investments	$	90,770	$	101,765	$	—	$	192,535

Schedule of Carrying Amounts and Estimated Fair Values of Convertible Note

The following table presents the carrying amounts and estimated fair values of our financial instruments that are not recorded at fair value on the condensed consolidated balance sheets (in thousands):

	As of April 30, 2018
	Net Carrying Amount Before Unamortized Debt Issuance Costs		Estimated Fair Value
	(unaudited)
Convertible senior notes	$	267,418	$	394,680