| Submission | Dec. 27, 2024 |
| Submission [Line Items] | |
| Central Index Key | 0000886128 |
| Registrant Name | FUELCELL ENERGY INC |
| Registration File Number | 333-274971 |
| Form Type | S-3 |
| Submission Type | POSASR |
| Fee Exhibit Type | EX-FILING FEES |
| Offerings | Dec. 27, 2024 USD ($) |
| Offering: 1 | |
| Offering: | |
| Rule 457(o) | true |
| Security Type | Equity |
| Security Class Title | Common Stock, par value $0.0001 |
| Fee Rate | 0.01531% |
| Offering: 2 | |
| Offering: | |
| Rule 457(o) | true |
| Security Type | Other |
| Security Class Title | Warrants |
| Fee Rate | 0.01531% |
| Offering: 3 | |
| Offering: | |
| Rule 457(o) | true |
| Security Type | Other |
| Security Class Title | Units |
| Fee Rate | 0.01531% |
| Offering: 4 | |
| Offering: | |
| Fee Previously Paid | false |
| Rule 457(o) | true |
| Security Type | Unallocated (Universal) Shelf |
| Maximum Aggregate Offering Price | $ 405,000,000 |
| Fee Rate | 0.01531% |
| Amount of Registration Fee | $ 62,005.50 |
| Offering Note | (1) We are registering hereunder such indeterminate number of each identified class of securities up to a proposed aggregate offering price of $405,000,000, which may be offered by us from time to time in unspecified numbers and at indeterminate prices, and as may be issued upon conversion, exercise, redemption, repurchase or exchange of any securities registered hereunder, including any applicable anti-dilution provisions. Pursuant to Rule 416 under the Securities Act of 1933, as amended (the "Securities Act"), the securities being registered hereunder include such indeterminate number of shares of common stock as may be issuable with respect to the securities being registered hereunder as a result of stock splits, stock dividends or similar transactions. (2) The proposed maximum aggregate offering price per class of security will be determined from time to time by the registrant in connection with the issuance by the registrant of the securities registered hereunder and is not specified as to each class of security pursuant to Instruction 2.A.iii.b. of the Instructions to the Calculation of Filing Fee Tables and Related Disclosure under Item 16(b) of Form S-3 under the Securities Act. |
| Fees Summary | Dec. 27, 2024 USD ($) |
| Fees Summary [Line Items] | |
| Total Offering | $ 405,000,000 |
| Previously Paid Amount | 0 |
| Total Fee Amount | 62,005.50 |
| Total Offset Amount | 0 |
| Net Fee | $ 62,005.50 |
