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Nature of Business and Basis of Presentation (Details)
 3 Months Ended
Jan. 31, 2015
Jan. 31, 2014
POSCO Energy [Member]    
Common stock ownership percentage 11.00%fcel_CommonStockOwnershipPercentage
/ us-gaap_MajorCustomersAxis
= fcel_PoscoEnergyMember		  
significant customer revenue percentage 54.00%fcel_SignificantCustomerRevenuePercentage
/ us-gaap_MajorCustomersAxis
= fcel_PoscoEnergyMember		 73.00%fcel_SignificantCustomerRevenuePercentage
/ us-gaap_MajorCustomersAxis
= fcel_PoscoEnergyMember
NRG Energy [Member]    
Common stock ownership percentage 6.00%fcel_CommonStockOwnershipPercentage
/ us-gaap_MajorCustomersAxis
= fcel_NRGEnergyMember		  
significant customer revenue percentage 5.00%fcel_SignificantCustomerRevenuePercentage
/ us-gaap_MajorCustomersAxis
= fcel_NRGEnergyMember		 0.00%fcel_SignificantCustomerRevenuePercentage
/ us-gaap_MajorCustomersAxis
= fcel_NRGEnergyMember