Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Tax Disclosure [Abstract]
Expected provision at statutory federal rate	$ (20,124)	$ (11,254)	$ (16,267)
Tax credits	(5,798)	(2,408)	(1,327)
Change in valuation allowance	47,412	17,487	1,528
Share-based compensation	(22,009)	(4,631)	4,430
Impact of tax reform	0	0	11,125
Other	633	1,099	204
Total income tax provision (benefit)	$ 114	$ 293	$ (307)

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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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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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