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Nature of Business and Basis of Presentation - Additional Information (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Jul. 31, 2018 | Jul. 31, 2017 | Jul. 31, 2018 | Jul. 31, 2017
POSCO Energy [Member] |  |  |  |
Nature Of Business And Basis Of Presentation [Line Items] |  |  |  |
Common stock ownership percentage | 2.80% |  | 2.80% |
Significant customer revenue percentage | 10.00% | 13.00% | 6.00% | 9.00%
NRG Energy, Inc. [Member] |  |  |  |
Nature Of Business And Basis Of Presentation [Line Items] |  |  |  |
Common stock ownership percentage | 1.50% |  | 1.50% |
Significant customer revenue percentage | 20.00% | 0.60% | 18.00% | 0.40%

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- Definition Common stock ownership percentage. + References No definition available. + Details
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- Definition Nature of business and basis of presentation. + References No definition available. + Details
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- Definition Percent of consolidated revenue by customer. + References No definition available. + Details
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- Details
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- Details
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