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Income Taxes - Additional Information (Details) - USD ($)
 2 Months Ended 3 Months Ended
Dec. 31, 2017
Jan. 31, 2019
Jan. 31, 2018
Operating Loss Carryforwards [Line Items]      
Income tax expense (benefit)   $ 0 $ 3,035,000
U.S. federal corporate tax rate 34.00% 21.00%  
Reduction of valuation allowance attributable to deferred tax assets   $ 2,000,000  
IPR&D      
Operating Loss Carryforwards [Line Items]      
Reduction in deferred tax liability   $ 1,000,000