Shareholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Apr. 30, 2017	Oct. 31, 2016	Apr. 30, 2016
NRG Energy, Inc. [Member]
Stockholders' Equity Note
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 40.20
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	200,000
Series A Warrant [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding	7,680,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5.83
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	7,680,000		0
Series B Warrant [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding	4,926,000	3,826,000
Common Stock [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues	7,200,000
Stock issued during period on open market, net of fees	$ 12.4