Accounts Receivable, Net - Additional Information (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 100	$ 100
POSCO Energy [Member]
Accounts Notes And Loans Receivable [Line Items]
Accounts Receivable, Related Parties, Current	12,200	6,200
NRG Energy, Inc. [Member]
Accounts Notes And Loans Receivable [Line Items]
Accounts Receivable, Related Parties, Current	$ 20	$ 100