Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Income Tax Disclosure [Abstract]
Income tax expense computed at federal statutory rate	$ (112,778)	$ (72,984)	$ (37,214)
State taxes, net of federal benefit	14,818	(12,239)	(6,168)
Research and development credits	(56,633)	(5,805)	(5,278)
Stock-based compensation	(246,363)	6,905	1,150
Change in valuation allowance	391,659	83,966	47,521
Other	11,359	1,150	809
Provision for income taxes	$ 2,062	$ 993	$ 820

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for award under share-based payment arrangement. Includes, but is not limited to, expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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