Income Taxes - Effective Income Tax Rate (Details)	12 Months Ended
Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Income tax rate reconciliation:
Provision at statutory rate	21.00%	23.41%	35.00%
Deferred tax assets remeasurement	0.00%	294.56%	0.00%
Base Erosion and Anti-Abuse Tax	3.60%	0.00%	0.00%
State taxes	2.18%	(0.16%)	2.29%
Foreign taxes	(0.37%)	1.22%	(0.35%)
Research and development credit	(7.53%)	(8.80%)	(15.38%)
Non-deductible compensation	1.01%	3.39%	3.45%
Fair value of debt conversion liability	0.00%	1.90%	0.00%
Transition tax	0.29%	23.23%	0.00%
Valuation allowance	(2.13%)	(11.95%)	(739.97%)
Other	1.03%	4.88%	6.67%
Effective income tax rate	19.08%	331.68%	(708.29%)

Effective Income Tax Rate Reconciliation, Base Erosion and Anti-Abuse Tax, Percent

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Effective Income Tax Rate Reconciliation, Change in Tax Rate, Deferred Tax Asset, Tax Cuts and Jobs Act, Percent

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Effective Income Tax Rate Reconciliation, Embedded Derivative, Percent

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Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost and Other

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Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Transition Tax on Accumulated Foreign Earnings, Percent

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

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage 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 changes in the valuation allowance for deferred tax assets.

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Percentage 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 applicable to statutory income tax expense (benefit) outside of the country of domicile.

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

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Percentage 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 applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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