Capacity of plant.

No definition available.

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Namespace Prefix:	fcel_
Data Type:	num:powerItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash covenant minimum required percentage of unrestricted cash balance on outstanding loan balance and accounts payable.

+ References

No definition available.

+ Details

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- Definition

Common stock issued during period warrants exercised.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Common stock shares issued to warrant holders.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Debt instrument non-refundable fee paid.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Loan Advance

+ References

No definition available.

+ Details

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Namespace Prefix:	fcel_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of debt prepayment charge in after year one.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcel_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Percentage of debt prepayment charge in next twelve months.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcel_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of shares will receive upon stock conversion prior to execution of agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcel_
Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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Subsequent Events - Additional Information (Details)				3 Months Ended
Subsequent Events - Additional Information (Details)	Feb. 28, 2019 USD ($) MW	Feb. 21, 2019 shares	Mar. 28, 2018 USD ($)	Jan. 31, 2019 USD ($)	Apr. 01, 2019	Apr. 30, 2016 USD ($)
Subsequent Event [Member] \| Waiver Agreement [Member] \| Series C Preferred Stock [Member]
Subsequent Event [Line Items]
Percentage of shares will receive upon conversion prior to execution of waiver agreement		25.00%
Subsequent Event [Member] \| Exchange Agreement [Member]
Subsequent Event [Line Items]
Warrants exercised \| shares		7,680,000
Common stock issued to warrant holders \| shares		6,000,000
New Construction Loan Facility [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 23,000,000
Loan Advance	$ 9,600,000
Term Loan Maturity Date	Oct. 31, 2019
New Construction Loan Facility [Member] \| Subsequent Event [Member] \| one-month LIBOR [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate	2.25%
New Construction Loan Facility [Member] \| Subsequent Event [Member] \| Groton CT [Member]
Subsequent Event [Line Items]
Capacity of Plant \| MW	7.4
Hercules Capital, Inc. [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 25,000,000		$ 25,000,000
Loan Advance			$ 13,100,000
Debt instrument, basis spread on variable rate				4.50%
Term Loan Maturity Date				Apr. 01, 2020
Hercules Capital, Inc. [Member] \| Series C Preferred Stock [Member]
Subsequent Event [Line Items]
Cash covenant minimum required percentage of unrestricted cash balance on outstanding loan balance and accounts payable				75.00%
Hercules Capital, Inc. [Member] \| Scenario Forecast [Member]
Subsequent Event [Line Items]
Cash covenant minimum required percentage of unrestricted cash balance on outstanding loan balance and accounts payable					75.00%
Hercules Capital, Inc. [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Cash covenant minimum required percentage of unrestricted cash balance on outstanding loan balance and accounts payable	50.00%
Debt prepayment charge in first twelve months	2.00%
Debt prepayment charge thereafter	1.00%
Non-refundable fee paid	$ 250,000