Convertible Senior Notes - Components of Debt (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jan. 31, 2023	Jan. 31, 2022	Jul. 31, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Repayment of convertible senior notes		$ 145,704	$ 0
2027 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount					$ 1,000
Convertible Debt | 2023 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount		145,704		$ 145,704
Unamortized debt issuance costs	[1]	0		(248)
Repayment of convertible senior notes		(145,704)		0
Net carrying amount		0		145,456
Convertible Debt | 2026 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount		750,000		750,000
Non-cash interest expense converted to principal		37,722		27,997
Unamortized debt discount	[2]	(151,426)		(169,438)
Unamortized debt issuance costs	[2]	(17,301)		(19,359)
Net carrying amount		618,995		589,200
Convertible Debt | 2027 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount		575,000		575,000
Unamortized debt issuance costs	[3]	(7,231)		(7,995)
Net carrying amount		$ 567,769		$ 567,005

[1] Included in the condensed consolidated balance sheets within convertible senior notes, net and amortized over the remaining life of the 2023 Notes using the effective interest rate method. The effective interest rate was 0.41%.

[2] Included in the condensed consolidated balance sheets within convertible senior notes, net and amortized over the remaining life of the 2026 Notes using the effective interest rate method. The effective interest rate is 7.05%.

[3] Included in the condensed consolidated balance sheets within convertible senior notes, net and amortized over the remaining life of the 2027 Notes using the effective interest rate method. The effective interest rate is 0.52%.