Convertible Senior Notes - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021
Debt Instrument
Amortization of debt issuance costs			$ 5,484	$ 57,784
Convertible Senior Notes | 2023 Notes
Debt Instrument
Coupon interest expense	$ 971	$ 971	1,942	1,942
Amortization of debt discount (conversion option) (1)	0	8,379	0	16,335
Amortization of debt issuance costs	638	327	966	637
Total interest expense	1,609	9,677	2,908	18,914
Convertible Senior Notes | 2025 Notes
Debt Instrument
Coupon interest expense	2,426	2,426	4,852	4,852
Amortization of debt discount (conversion option) (1)	0	8,127	0	15,784
Amortization of debt issuance costs	642	224	866	435
Total interest expense	3,068	10,777	5,718	21,071
Convertible Senior Notes | 2026 Notes
Debt Instrument
Coupon interest expense	1,875	458	3,750	458
Amortization of debt discount (conversion option) (1)	0	2,960	0	2,960
Amortization of debt issuance costs	1,417	133	1,944	133
Total interest expense	3,292	3,551	5,694	3,551
Convertible Senior Notes | 2027 Notes
Debt Instrument
Coupon interest expense	3,558	3,558	7,116	7,116
Amortization of debt discount (conversion option) (1)	0	10,643	0	20,659
Amortization of debt issuance costs	1,274	433	1,708	841
Total interest expense	$ 4,832	$ 14,634	$ 8,824	$ 28,616