Nature of Business and Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Nature of Business and Basis of Presentation [Line items]
Debt issuance costs, deduction of current portion of debt	[1]	$ 129		$ 129		$ 152
Debt issuance costs, deduction of long-term debt and other liabilities	[2]	$ 161		$ 161		225
POSCO Energy [Member]
Nature of Business and Basis of Presentation [Line items]
Common stock ownership percentage		5.00%		5.00%
Significant customer revenue percentage		7.00%	52.00%	8.00%	48.00%
NRG Energy, Inc. [Member]
Nature of Business and Basis of Presentation [Line items]
Common stock ownership percentage		3.00%		3.00%
Significant customer revenue percentage		0.30%	0.40%	0.40%	0.20%
Accounting Standards Update 2015-03 [Member] | Current Assets [Member]
Nature of Business and Basis of Presentation [Line items]
Debt issuance costs, deduction of current portion of debt						300
Accounting Standards Update 2015-03 [Member] | Other Assets [Member]
Nature of Business and Basis of Presentation [Line items]
Debt issuance costs, deduction of long-term debt and other liabilities						$ 1,100

[1] Represents the current portion of direct deferred finance costs relate primarily to securing a $40.0 million loan facility with NRG which is being amortized over the five-year life of the facility.

[2] Represents the long-term portion of direct deferred finance costs relating to the Company’s loan facility with NRG which is being amortized over the five-year life of the facility.