Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009
Revenues:
Product sales and revenues	$ 115,104	$ 59,226	$ 73,804
Research and development contracts	7,466	10,551	14,212
Total revenues	122,570	69,777	88,016
Costs of revenues:
Cost of product sales and revenues	127,350	78,060	107,033
Cost of research and development contracts	7,830	10,370	10,994
Total cost of revenues	135,180	88,430	118,027
Gross loss	(12,610)	(18,653)	(30,011)
Operating expenses:
Administrative and selling expenses	16,299	17,150	17,194
Research and development expenses	16,768	18,562	19,160
Total operating expenses	33,067	35,712	36,354
Loss from operations	(45,677)	(54,365)	(66,365)
Interest expense	(2,578)	(127)	(265)
Income (loss) from equity investments	58	(730)	(812)
Interest and other income, net	2,861	1,354	860
Loss before redeemable preferred stock of subsidiary	(45,336)	(53,868)	(66,582)
Accretion of redeemable preferred stock of subsidiary	(525)	(2,367)	(2,092)
Loss before provision for income taxes	(45,861)	(56,235)	(68,674)
Provision for income taxes	(113)	(91)
Net loss	(45,974)	(56,326)	(68,674)
Net loss attributable to noncontrolling interest	261	663
Net loss attributable to FuelCell Energy, Inc.	(45,713)	(55,663)	(68,674)
FuelCell Ltd. (adjustment from Series 1 modification)	(8,987)
Preferred dividends - Series B	(3,200)	(3,201)	(3,208)
Net loss to common shareholders	$ (57,900)	$ (58,864)	$ (71,882)
Net loss to common shareholders per share
Basic	$ (0.47)	$ (0.63)	$ (0.99)
Diluted	$ (0.47)	$ (0.63)	$ (0.99)
Weighted average shares outstanding
Basic	124,498,073	93,925,863	72,392,928
Diluted	124,498,073	93,925,863	72,392,928