Income Taxes - Additional Information (Details) - USD ($) $ in Thousands |
2 Months Ended | 3 Months Ended | 6 Months Ended | 10 Months Ended | |
|---|---|---|---|---|---|
Dec. 31, 2017 |
Apr. 30, 2017 |
Apr. 30, 2018 |
Apr. 30, 2017 |
Oct. 31, 2018 |
|
| Operating Loss Carryforwards [Line Items] | |||||
| Income tax expense (benefit) | $ (36) | $ (3,035) | $ 45 | ||
| U.S. federal corporate tax rate | 34.00% | ||||
| Reduction of valuation allowance attributable to deferred tax assets | 2,000 | ||||
| IPR&D | |||||
| Operating Loss Carryforwards [Line Items] | |||||
| Reduction in deferred tax liability | $ 1,000 | ||||
| Scenario Plan [Member] | |||||
| Operating Loss Carryforwards [Line Items] | |||||
| U.S. federal corporate tax rate | 21.00% | ||||