Fair Value Measurements (Tables)

9 Months Ended

Oct. 31, 2020

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 that were measured at fair value on a recurring basis using the above input categories (in thousands):  

	As of October 31, 2020
	Level 1		Level 2		Level 3		Total
	(unaudited)
Assets:
Cash equivalents:
Money market funds	$	335,592	$	—	$	—	$	335,592
Total cash equivalents	335,592		—		—		335,592
Short-term investments:
U.S. treasury securities	—		1,797,157		—		1,797,157
Corporate debt securities	—		288,216		—		288,216
Total short-term investments	—		2,085,373		—		2,085,373
Total cash equivalents and short-term investments	$	335,592	$	2,085,373	$	—	$	2,420,965

	As of January 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	416,584	$	—	$	—	$	416,584
U.S. treasury securities	—		19,996		—		19,996
Total cash equivalents	416,584		19,996		—		436,580
Short-term investments:
U.S. treasury securities	—		576,598		—		576,598
Corporate debt securities	—		306,378		—		306,378
Total short-term investments	—		882,976		—		882,976
Total cash equivalents and short-term investments	$	416,584	$	902,972	$	—	$	1,319,556

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 October 31, 2020
	Net Carrying Amount (1)		Estimated Fair Value
	(unaudited)
2023 convertible senior notes	$	35,614	$	182,234
2025 convertible senior notes	$	876,852	$	1,393,052
2026 convertible senior notes	$	856,489	$	1,316,750

(1)     Before unamortized debt issuance costs.