Consolidated Statements of Operations - USD ($)		12 Months Ended
		Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Revenues:
Revenues		$ 89,437,000	$ 95,666,000	$ 108,252,000
Costs of revenues:
Costs of revenues		86,344,000	92,932,000	108,609,000
Gross profit (loss)		3,093,000	2,734,000	(357,000)
Operating expenses:
Administrative and selling expenses		24,908,000	25,916,000	25,150,000
Research and development expenses		22,817,000	20,398,000	20,846,000
Restructuring expense		0	1,355,000	0
Total operating expenses		47,725,000	47,669,000	45,996,000
Loss from operations		(44,632,000)	(44,935,000)	(46,353,000)
Interest expense		(9,055,000)	(9,171,000)	(4,958,000)
Other income, net		3,338,000	247,000	622,000
Loss before benefit (provision) for income taxes		(50,349,000)	(53,859,000)	(50,689,000)
Benefit (provision) for income taxes		3,015,000	(44,000)	(519,000)
Net loss		(47,334,000)	(53,903,000)	(51,208,000)
Net loss attributable to noncontrolling interest		0	0	251,000
Net loss attributable to FuelCell Energy, Inc.		(47,334,000)	(53,903,000)	(50,957,000)
Series B Preferred stock dividends		(3,200,000)	(3,200,000)	(3,200,000)
Series D Preferred stock redemption accretion		(2,075,000)
Net loss to common stockholders		$ (62,168,000)	$ (57,103,000)	$ (54,157,000)
Net loss to common stockholders per share
Basic		$ (0.75)	$ (1.14)	$ (1.82)
Diluted	[1]	$ (0.75)	$ (1.14)	$ (1.82)
Weighted average shares outstanding
Basic		82,754,268	49,914,904	29,773,700
Diluted		82,754,268	49,914,904	29,773,700
Series B Preferred Stock [Member]
Operating expenses:
Series B Preferred stock dividends		$ (3,200,000)	$ (3,200,000)	$ (3,200,000)
Series C Preferred Stock [Member]
Operating expenses:
Series C Preferred stock deemed dividends		(9,559,000)	0	0
Series D Preferred Stock [Member]
Operating expenses:
Series D Preferred stock redemption accretion		(2,075,000)	0	0
Product Sales [Member]
Revenues:
Revenues		52,490,000	43,047,000	62,563,000
Costs of revenues:
Costs of revenues		54,504,000	49,843,000	63,474,000
Service Agreements and License Revenues [Member]
Revenues:
Revenues		15,757,000	27,050,000	31,491,000
Costs of revenues:
Costs of revenues		15,059,000	25,285,000	32,592,000
Generation Revenues [Member]
Revenues:
Revenues		7,171,000	7,233,000	1,267,000
Costs of revenues:
Costs of revenues		6,421,000	5,076,000	664,000
Advanced Technologies Contract Revenues [Member]
Revenues:
Revenues		14,019,000	18,336,000	12,931,000
Costs of revenues:
Costs of revenues		$ 10,360,000	$ 12,728,000	$ 11,879,000

[1] Due to the net loss to common stockholders in each of the years presented above, diluted earnings per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive.