Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jan. 31, 2024	Jan. 31, 2023
Revenues:
Total revenues	$ 16,691	$ 37,073
Costs of revenues:
Total costs of revenues	28,416	31,836
Gross (loss) profit	(11,725)	5,237
Operating expenses:
Administrative and selling expenses	16,400	15,009
Research and development expenses	14,353	12,683
Total costs and expenses	30,753	27,692
Loss from operations	(42,478)	(22,455)
Interest expense	(2,338)	(1,512)
Interest income	4,067	3,410
Other (expense) income, net	(3,650)	49
Loss before provision for income taxes	(44,399)	(20,508)
Provision for income taxes		(578)
Net loss	(44,399)	(21,086)
Net loss attributable to noncontrolling interests	(24,606)	(2,464)
Net loss attributable to FuelCell Energy, Inc.	(19,793)	(18,622)
Series B preferred stock dividends	(800)	(800)
Net loss attributable to common stockholders	$ (20,593)	$ (19,422)
Loss per share basic and diluted:
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.05)	$ (0.05)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.05)	$ (0.05)
Basic weighted average shares outstanding (in shares)	451,637,041	405,803,753
Diluted weighted average shares outstanding (in shares)	451,637,041	405,803,753
Net loss	$ (44,399)	$ (21,086)
Other comprehensive loss:
Foreign currency translation adjustments	33	447
Total comprehensive loss	(44,366)	(20,639)
Comprehensive loss attributable to noncontrolling interests	(24,606)	(2,464)
Comprehensive loss attributable to FuelCell Energy, Inc.	(19,760)	(18,175)
Series B Preferred Stock
Operating expenses:
Series B preferred stock dividends	(800)	(800)
Product
Revenues:
Total revenues		9,095
Costs of revenues:
Total costs of revenues	2,391	1,029
Service
Revenues:
Total revenues	1,617	13,882
Costs of revenues:
Total costs of revenues	1,888	10,945
Generation
Revenues:
Total revenues	10,493	9,557
Costs of revenues:
Total costs of revenues	20,894	16,602
Advanced Technologies
Revenues:
Total revenues	4,581	4,539
Costs of revenues:
Total costs of revenues	$ 3,243	$ 3,260