Nature of Business and Basis of Presentation (Details) (USD $)	3 Months Ended					5 Months Ended		12 Months Ended
	Oct. 31, 2012		Oct. 31, 2011		Apr. 30, 2011	Oct. 31, 2011		Oct. 31, 2012		Oct. 31, 2011		Oct. 31, 2010	Oct. 31, 2009
Restricted Cash and Cash Equivalents, Current	$ 10,600,000							$ 10,600,000
Letters of Credit Outstanding, Amount	9,600,000		7,100,000			7,100,000		9,600,000		7,100,000
Accrued Contract and Operating Costs	39,000	[1]	88,000	[1]		88,000	[1]	39,000	[1]	88,000	[1]
Product Warranty Accrual	2,317,000	[2]	1,134,000	[2]		1,134,000	[2]	2,317,000	[2]	1,134,000	[2]
Loss Reserve on Service Agreements	5,000,000		8,900,000			8,900,000		5,000,000		8,900,000
Long-term stack residual value	14,316,000		15,092,000			15,092,000		14,316,000		15,092,000
Accumulated depreciation on long-term stacks	7,600,000		2,400,000			2,400,000		7,600,000		2,400,000
Charge for Repair and Upgrade	600,000		600,000		8,800,000
Reduction in Repair and Upgrade Accrual						500,000
Reserve for Repair and Upgrade Program	4,753,000	[3]	7,949,000	[3]		7,949,000	[3]	4,753,000	[3]	7,949,000	[3]
Costs for Repair and Upgrades						2,900,000		3,700,000
license fee income								1,000,000		1,000,000
royalty percentage								4.10%					4.10%
Common stock ownership percentage	16.00%							16.00%
significant customer revenue percentage								86.00%		71.00%		68.00%
Minimum Annual Royalties Under Agreement								800,000		600,000
Upfront License Fee													10,000,000
Future License Fees To Be Paid	8,000,000							8,000,000
Reserve for Performance Guarantees	2,200,000		2,200,000			2,200,000		2,200,000		2,200,000
Reduced royalty percentage								3.00%
Comprehensive Income (Loss), Net of Tax, Attributable to Parent								35,600,000		45,700,000		55,700,000
Net Income (Loss) Attributable to Parent			(45,700,000)					35,495,000		45,713,000		55,663,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax								51,000		4,000		13,000
POSCO Energy [Member]
significant customer revenue percentage								76.00%		44.00%		58.00%
Department of Energy [Member]
significant customer revenue percentage								7.00%		0.00%		0.00%
BioFuels Fuel Cells [Member]
significant customer revenue percentage								0.00%		12.00%		0.00%
UTS Bioenergy [Member]
significant customer revenue percentage								2.00%		10.00%		0.00%
Pacific Gas and Electric [Member]
significant customer revenue percentage								1.00%		5.00%		10.00%
FCES Germany [Member]
Noncontrolling Interest, Ownership Percentage by Parent	75.00%							75.00%
Alliance Entities [Member]
Noncontrolling Interest, Ownership Percentage by Parent	80.00%							80.00%
CANADA
Foreign Currency Transaction Gain (Loss), Unrealized								$ 100,000		$ 1,000,000		$ 10,000

[1] Balance includes estimated losses accrued on product sales contracts.

[2] Activity in the reserve for product warranty costs during the year ended October 31, 2012 and 2011 included additions for estimates of potential future warranty obligations of $3.1 million and $0.9 million, respectively, on contracts in the warranty period and reserve reductions related to actual warranty spend and reversals to income of $1.9 million and $0.5 million, respectively, as contracts progress through the warranty period or are beyond the warranty period.

[3] During the second quarter of fiscal 2011, the Company incurred an obligation to repair and upgrade a select group of 1.2 megawatt (MW) fuel cell modules produced between 2007 and early 2009. The repair and upgrade obligation was based on events that occurred and knowledge obtained concerning the performance of this select group of modules during the second fiscal quarter of 2011 however, the formal agreement to begin the repair and upgrade program was not finalized until May 2011. The program commenced in the third quarter of 2011 and with the exception of providing replacement modules to POSCO, has concluded during fiscal year 2012. The Company recorded a charge of approximately $8.8 million during the quarter ended April 30, 2011 recorded as a cost of product sales and revenues on the consolidated statements of operations. The charge consisted of the costs associated with the replacement of modules of $9.5 million and the costs associated with the repair of other modules of $4.1 million, partially off-set by the estimated fair value at the end of the respective SA contract terms for upgraded assets being deployed in the program of approximately $4.8 million, which will be returned to the Company at the expiration of the respective LTSA agreements if the customer does not renew the SA agreement through at least the remaining useful life of the upgraded assets. For the remainder of fiscal 2011 since April 30, 2011, the Company incurred actual repair and upgrade costs of approximately $2.9 million and reduced its estimate for future repair costs under this program resulting in a benefit to cost of product sales and revenues of $0.5 million. For the year ended October 31, 2012, the Company incurred actual repair and upgrade costs of approximately $3.7 million and increased the reserve by $0.6 million during the fourth quarter of 2012 to adjust for the cost of modules which are expected to be provided to POSCO in accordance with the B1200 repair campaign when needed.