Convertible Senior Notes, Net - Schedule of Interest Expense (Details) - Senior Notes - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021
2023 convertible senior notes
Debt Instrument [Line Items]
Contractual interest expense	$ 3	$ 14	$ 11	$ 34
Amortization of debt issuance costs	11	24	27	62
Amortization of debt discount		241		624
Total	14	279	38	720
2025 convertible senior notes
Debt Instrument [Line Items]
Contractual interest expense	331	331	662	662
Amortization of debt issuance costs	808	568	1,615	1,124
Amortization of debt discount		8,790		17,490
Total	1,139	9,689	2,277	19,276
2026 convertible senior notes
Debt Instrument [Line Items]
Contractual interest expense	1,078	1,078	2,156	2,156
Amortization of debt issuance costs	627	352	1,253	692
Amortization of debt discount		11,474		22,788
Total	$ 1,705	$ 12,904	$ 3,409	$ 25,636