Cash Equivalents and Short-term Investments (Tables)

9 Months Ended

Oct. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Costs, Unrealized Gains and Losses and Estimated Fair Value of 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 October 31, 2020 and January 31, 2020 were as follows (in thousands):  

	As of October 31, 2020
	Amortized Cost		Unrealized Gain		Unrealized Loss		Estimated Fair Value
	(unaudited)
Cash equivalents:
Money market funds	$	335,592	$	—	$	—	$	335,592
Total cash equivalents	335,592		—		—		335,592
Short-term investments:
U.S. treasury securities	1,795,309		1,978		(130)		1,797,157
Corporate debt securities	287,523		722		(29)		288,216
Total short-term investments	2,082,832		2,700		(159)		2,085,373
Total	$	2,418,424	$	2,700	$	(159)	$	2,420,965

	As of January 31, 2020
	Amortized Cost		Unrealized Gain		Unrealized Loss		Estimated Fair Value
Cash equivalents:
Money market funds	$	416,584	$	—	$	—	$	416,584
U.S. treasury securities	19,996		—		—		19,996
Total cash equivalents	436,580		—		—		436,580
Short-term investments:
U.S. treasury securities	575,920		686		(8)		576,598
Corporate debt securities	305,859		519		—		306,378
Total short-term investments	881,779		1,205		(8)		882,976
Total	$	1,318,359	$	1,205	$	(8)	$	1,319,556

Schedule of Contractual Maturities of Short-term Investments

The following table presents the contractual maturities of the Company’s short-term investments as of October 31, 2020 (in thousands):

	As of October 31, 2020
	Amortized Cost		Estimated Fair Value
	(unaudited)
Due within one year	$	1,285,936	$	1,288,279
Due between one to five years	796,896		797,094
Total	$	2,082,832	$	2,085,373