Nature of Business and Basis of Presentation (Policies)	9 Months Ended
Jul. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial information. Accordingly, they do not contain all of the information and footnotes required by accounting principles generally accepted in the United States of America (“GAAP”) for complete financial statements. In the opinion of management, all normal and recurring adjustments necessary to fairly present the Company’s financial position and results of operations as of and for the three and nine months ended July 31, 2019 and 2018 have been included. All intercompany accounts and transactions have been eliminated. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. The balance sheet as of October 31, 2018 has been derived from the audited financial statements at that date, but it does not include all of the information and footnotes required by GAAP for complete financial statements. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto for the fiscal year ended October 31, 2018, which are contained in the Company’s Annual Report on Form 10-K previously filed with the SEC. The results of operations for the interim periods presented are not necessarily indicative of results that may be expected for any other interim period or for the full fiscal year. On May 8, 2019 at 5:00 p.m. Eastern time, the Company effected a 1-for-12 reverse stock split, reducing the number of the Company’s common shares outstanding on that date from 183,411,230 shares to 15,284,269 shares. The number of authorized shares of common stock remains unchanged at 225,000,000 shares and the number of authorized shares of preferred stock remains unchanged at 250,000 shares. Additionally, the conversion rate of our Series B Preferred Stock (as defined elsewhere herein), the conversion price of our Series C Preferred Stock and Series D Preferred Stock (each as defined elsewhere herein), the exchange price of our Series 1 Preferred Shares (as defined elsewhere herein), the exercise price of all then outstanding options and warrants, and the number of shares reserved for future issuance pursuant to our equity compensation plans were all adjusted proportionately in connection with the reverse stock split. All share and per share amounts and conversion prices presented herein have been adjusted retroactively to reflect these changes. Certain reclassifications have been made to the prior year amounts to conform to the current year presentation. The Company adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)” effective November 1, 2018 and applied the modified retrospective transition method. As a result of the adoption of this ASU, Unbilled receivables has been reclassified as a separate line item from Accounts receivable, net on the Consolidated Balance Sheets and Unbilled receivables has been classified as a separate item from Accounts receivable, net in the Consolidated Statement of Cash Flows for the prior year period.
Going Concern and Liquidity Considerations	Going Concern and Liquidity Considerations The Company’s consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The Company has significant short-term debt and other obligations currently due or maturing in less than one year, which are in excess of the Company’s cash and current asset balance. Due to the Company’s constrained liquidity, the Company has been delaying certain payments to third parties, including trade creditors, to conserve cash. Management has been actively working with trade creditors, and entering into forbearance agreements and payment arrangements. However, the Company may not be able to enter into forbearance agreements or make suitable payment arrangements with its trade creditors, or the terms of any forbearance agreements or payment arrangements may not be favorable to the Company. If the Company is unable to negotiate such forbearance agreements or payment arrangements, trade creditors whose payments have been delayed may take action against the Company, including, but not limited to, filing litigation, arbitration or other proceedings against the Company. Going forward, suppliers may require changes to payment terms and advance payments which may create an additional strain on liquidity. The Company has entered into a series of amendments to its senior secured debt facility with its senior lender Hercules Capital, Inc. (“Hercules”) in order to, among other things, provide for a lower minimum cash covenant, obtain a waiver of the minimum cash covenant during certain amendment periods, and avoid events of default and acceleration of amounts due under the loan agreement. Most recently, Hercules provided an amendment through September 30, 2019, which would extend to October 22, 2019 if the outstanding loan balance is less than or equal to $5.0 million on or before September 30, 2019. As of September 4, 2019, the outstanding principal balance under the Hercules facility totaled approximately $5.6 million. In exchange for these amendments, the Company has paid down the principal balance under the Hercules facility and agreed to make additional principal payments equal to 30% of the net proceeds of stock sales under the Company’s at-the-market sales agreement, as further described in Note 17. “Debt and Financing Obligation” and Note 20. “Subsequent Events”. As of July 31, 2019, the Company had an accumulated deficit from recurring net losses for the current and prior years. These factors as well as negative cash flows from operating and investing activities and negative working capital raise substantial doubt about the Company’s ability to continue as a going concern. Management is working to address the Company’s current liquidity position through the exploration of various alternatives, including, but not limited to, refinancing the Company’s senior secured credit facility with Hercules; retaining existing project financing facilities and securing additional project financing facilities (including construction and term debt facilities and tax equity financing); potential sales of the Company’s assets, its intellectual property, or all or part of its business; potential licensing of certain of the Company’s technology and intellectual property; implementing cost reduction measures such as the reduction in force implemented in April; increasing sales activity related to the Company’s products; negotiating and entering into advanced technology research and development contracts; and sales of common stock or other equity securities directly to investors or through the Company’s at-the-market sales plan. Notwithstanding the Company’s efforts, the Company may not be able to refinance the Hercules credit facility on acceptable terms, or at all, retain existing project financing facilities or secure additional project financing facilities on acceptable terms, or at all, consummate any sale of its assets or all or part of its business, any sale or license of any of its intellectual property, or any sale of equity securities, implement further cost reduction measures, increase its sales activity, or successfully negotiate and enter into advanced technology contracts. Although the maturity date of the Hercules credit facility is April 1, 2020, the waiver by Hercules of certain covenants (including the minimum unrestricted cash covenant) expires by September 30, 2019 (or October 22, 2019 if the Hercules loan balance is less than or equal to $5.0 million on or before September 30, 2019). Accordingly, if the Company is not able to refinance the Hercules credit facility, and if Hercules is not willing to provide further accommodations, the Company may not meet certain covenant requirements and as a result may default on its obligations under its senior secured credit facility with Hercules. The occurrence of an event of default under the Hercules credit facility also constitutes or may result in an event of default under, and causes or may cause the acceleration of, a number of material financial obligations of the Company, including the loan from the State of Connecticut, the loan from Connecticut Green Bank, and the project finance facilities with Generate Lending, LLC (“Generate Lending”), PNC Energy Capital, LLC (“PNC”), and Fifth Third Bank (“Fifth Third”). The occurrence of an event of default under the Hercules credit facility also constitutes a triggering event under the Certificate of Designations, Preferences and Rights of the Series D Convertible Preferred Stock of the Company. At the project finance level, as further described in Note 17. “Debt and Financing Obligation” and Note 20. “Subsequent Events”, the Company has outstanding construction loans from NRG Energy, Inc. (“NRG”), Generate Lending and Fifth Third. Under the most recent amendment to the loan agreement with NRG, the maturity date of each note payable to NRG is now the date that is the earliest of (a) September 30, 2019, (b) the commercial operation date or substantial completion date, as applicable, with respect to the fuel cell project owned by the co-borrower under such note, and (c) the repayment in full or the closing of a refinancing of the Company’s indebtedness with Hercules. NRG may also accelerate the maturity dates if it determines, in its sole discretion, that the Company is not making sufficient progress towards the completion of the construction of the 2.8 MW Tulare BioMAT project in California. If the Company is unable to make sufficient progress toward the completion of such project or to obtain another amendment, extension or refinancing, the Company may default on the NRG loan. The occurrence of an event of default under the NRG loan agreement may result in the principal and all accrued interest becoming immediately due and payable. Under the most recent amendment to the loan agreement with Generate Lending, Generate Lending has a call right, which may be exercised during the period beginning on September 1, 2019 and ending on (and including) September 30, 2019 (which period may be further extended by mutual agreement of the parties), and which, if exercised, would require payment of all outstanding loans from Generate Lending (which are further described in Note 17. “Debt and Financing Obligations”) and all accrued and unpaid interest thereon on September 30, 2019. If Generate Lending calls the loan or determines to cease lending under its construction loan facility, the Company will be required to pursue alternative financing for the Company’s generation backlog. If the Company is unable to obtain such financing, it may result in delays in project execution and potential termination or events of default under certain power purchase agreements. Finally, under the most recent amendment to the construction loan agreement with Fifth Third, the Company has agreed (among other things) that, no later than September 28, 2019, it will deliver to Fifth Third a binding loan agreement for permanent financing from another lender and one or more binding letters of intent from tax equity investors in an amount of at least $18.0 million, provided that such date will be automatically extended to October 21, 2019 in the event that the Hercules credit facility is repaid or extended beyond October 21, 2019, and further provided that both dates could be extended by an additional 60 days due to delays outside of the control of the Company or if Fifth Third is reasonably satisfied that the Company is negotiating diligently and in good faith with potential take-out lenders or tax equity investors. If the Company is unable to obtain a binding loan agreement for permanent financing from another lender and one or more binding letters of intent from tax equity investors in an amount of at least $18.0 million, and if Fifth Third does not provide further accommodation, the Company may default on the Fifth Third loan. The occurrence of an event of default under the Fifth Third loan may result in the principal and all accrued interest becoming immediately due and payable. Should these obligations to NRG, Generate Lending and Fifth Third mature as described above without further extension or amendment, the Company may not have the liquidity to repay such obligations. The occurrence of an event of default under any of these project finance agreements also constitutes or may result in an event of default under, and causes or may cause the acceleration of amounts due under these agreements and a number of other material financial obligations of the Company, including the Hercules facility, the loan from the State of Connecticut, the financing agreements with PNC and the loan from the Connecticut Green Bank. The terms of any financing and other measures to obtain funds that may be undertaken by the Company may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain and retain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development efforts and commercialization efforts and accelerate its exploration of potential sales of its intellectual property, other assets, and business, any of which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue its business plans, there is no assurance that the Company will be successful in obtaining and retaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. If the Company is unable to obtain external financing and/or increase liquidity through sales of its assets, its intellectual property or all or part of its business or through licensing of its technology and intellectual property, it may not be able to sustain future operations. As a result, the Company may be required to delay, reduce and/or cease its operations and/or seek bankruptcy protection. Based on its recurring losses from operations, expectation of continuing operating losses for the foreseeable future, negative working capital, and need to raise additional capital to finance its future operations, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year after the date of filing of this Quarterly Report on Form 10-Q. The Company’s financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.
Use Of Estimates	Use of Estimates The preparation of financial statements and related disclosures in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent liabilities. Estimates are used in accounting for, among other things, revenue recognition, contract loss accruals, excess, slow-moving and obsolete inventories, product warranty accruals, loss accruals on service agreements, share-based compensation expense, allowance for doubtful accounts, depreciation and amortization, impairment of goodwill and in-process research and development intangible assets, impairment of long-lived assets (including project assets), income taxes, contingencies and valuing assets acquired and pre-existing contractual arrangements settled in the acquisition of Bridgeport Fuel Cell, LLC. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Due to the inherent uncertainty involved in making estimates, actual results in future periods may differ from those estimates.

Nature of Business and Basis of Presentation (Policies)

9 Months Ended

Jul. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

The accompanying unaudited consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial information. Accordingly, they do not contain all of the information and footnotes required by accounting principles generally accepted in the United States of America (“GAAP”) for complete financial statements. In the opinion of management, all normal and recurring adjustments necessary to fairly present the Company’s financial position and results of operations as of and for the three and nine months ended July 31, 2019 and 2018 have been included. All intercompany accounts and transactions have been eliminated.

Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. The balance sheet as of October 31, 2018 has been derived from the audited financial statements at that date, but it does not include all of the information and footnotes required by GAAP for complete financial statements. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto for the fiscal year ended October 31, 2018, which are contained in the Company’s Annual Report on Form 10-K previously filed with the SEC. The results of operations for the interim periods presented are not necessarily indicative of results that may be expected for any other interim period or for the full fiscal year.

On May 8, 2019 at 5:00 p.m. Eastern time, the Company effected a 1-for-12 reverse stock split, reducing the number of the Company’s common shares outstanding on that date from 183,411,230 shares to 15,284,269 shares. The number of authorized shares of common stock remains unchanged at 225,000,000 shares and the number of authorized shares of preferred stock remains unchanged at 250,000 shares. Additionally, the conversion rate of our Series B Preferred Stock (as defined elsewhere herein), the conversion price of our Series C Preferred Stock and Series D Preferred Stock (each as defined elsewhere herein), the exchange price of our Series 1 Preferred Shares (as defined elsewhere herein), the exercise price of all then outstanding options and warrants, and the number of shares reserved for future issuance pursuant to our equity compensation plans were all adjusted proportionately in connection with the reverse stock split. All share and per share amounts and conversion prices presented herein have been adjusted retroactively to reflect these changes.

Certain reclassifications have been made to the prior year amounts to conform to the current year presentation. The Company adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)” effective November 1, 2018 and applied the modified retrospective transition method. As a result of the adoption of this ASU, Unbilled receivables has been reclassified as a separate line item from Accounts receivable, net on the Consolidated Balance Sheets and Unbilled receivables has been classified as a separate item from Accounts receivable, net in the Consolidated Statement of Cash Flows for the prior year period.

Going Concern and Liquidity Considerations

The Company’s consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities and commitments in the normal course of business. The Company has significant short-term debt and other obligations currently due or maturing in less than one year, which are in excess of the Company’s cash and current asset balance. Due to the Company’s constrained liquidity, the Company has been delaying certain payments to third parties, including trade creditors, to conserve cash. Management has been actively working with trade creditors, and entering into forbearance agreements and payment arrangements. However, the Company may not be able to enter into forbearance agreements or make suitable payment arrangements with its trade creditors, or the terms of any forbearance agreements or payment arrangements may not be favorable to the Company. If the Company is unable to negotiate such forbearance agreements or payment arrangements, trade creditors whose payments have been delayed may take action against the Company, including, but not limited to, filing litigation, arbitration or other proceedings against the Company. Going forward, suppliers may require changes to payment terms and advance payments which may create an additional strain on liquidity.

The Company has entered into a series of amendments to its senior secured debt facility with its senior lender Hercules Capital, Inc. (“Hercules”) in order to, among other things, provide for a lower minimum cash covenant, obtain a waiver of the minimum cash covenant during certain amendment periods, and avoid events of default and acceleration of amounts due under the loan agreement. Most recently, Hercules provided an amendment through September 30, 2019, which would extend to October 22, 2019 if the outstanding loan balance is less than or equal to $5.0 million on or before September 30, 2019. As of September 4, 2019, the outstanding principal balance under the Hercules facility totaled approximately $5.6 million. In exchange for these amendments, the Company has paid down the principal balance under the Hercules facility and agreed to make additional principal payments equal to 30% of the net proceeds of stock sales under the Company’s at-the-market sales agreement, as further described in Note 17. “Debt and Financing Obligation” and Note 20. “Subsequent Events”.

As of July 31, 2019, the Company had an accumulated deficit from recurring net losses for the current and prior years. These factors as well as negative cash flows from operating and investing activities and negative working capital raise substantial doubt about the Company’s ability to continue as a going concern.

Management is working to address the Company’s current liquidity position through the exploration of various alternatives, including, but not limited to, refinancing the Company’s senior secured credit facility with Hercules; retaining existing project financing facilities and securing additional project financing facilities (including construction and term debt facilities and tax equity financing); potential sales of the Company’s assets, its intellectual property, or all or part of its business; potential licensing of certain of the Company’s technology and intellectual property; implementing cost reduction measures such as the reduction in force implemented in April; increasing sales activity related to the Company’s products; negotiating and entering into advanced technology research and development contracts; and sales of common stock or other equity securities directly to investors or through the Company’s at-the-market sales plan. Notwithstanding the Company’s efforts, the Company may not be able to refinance the Hercules credit facility on acceptable terms, or at all, retain existing project financing facilities or secure additional project financing facilities on acceptable terms, or at all, consummate any sale of its assets or all or part of its business, any sale or license of any of its intellectual property, or any sale of equity securities, implement further cost reduction measures, increase its sales activity, or successfully negotiate and enter into advanced technology contracts. Although the maturity date of the Hercules credit facility is April 1, 2020, the waiver by Hercules of certain covenants (including the minimum unrestricted cash covenant) expires by September 30, 2019 (or October 22, 2019 if the Hercules loan balance is less than or equal to $5.0 million on or before September 30, 2019). Accordingly, if the Company is not able to refinance the Hercules credit facility, and if Hercules is not willing to provide further accommodations, the Company may not meet certain covenant requirements and as a result may default on its obligations under its senior secured credit facility with Hercules. The occurrence of an event of default under the Hercules credit facility also constitutes or may result in an event of default under, and causes or may cause the acceleration of, a number of material financial obligations of the Company, including the loan from the State of Connecticut, the loan from Connecticut Green Bank, and the project finance facilities with Generate Lending, LLC (“Generate Lending”), PNC Energy Capital, LLC (“PNC”), and Fifth Third Bank (“Fifth Third”). The occurrence of an event of default under the Hercules credit facility also constitutes a triggering event under the Certificate of Designations, Preferences and Rights of the Series D Convertible Preferred Stock of the Company.

At the project finance level, as further described in Note 17. “Debt and Financing Obligation” and Note 20. “Subsequent Events”, the Company has outstanding construction loans from NRG Energy, Inc. (“NRG”), Generate Lending and Fifth Third. Under the most recent amendment to the loan agreement with NRG, the maturity date of each note payable to NRG is now the date that is the earliest of (a) September 30, 2019, (b) the commercial operation date or substantial completion date, as applicable, with respect to the fuel cell project owned by the co-borrower under such note, and (c) the repayment in full or the closing of a refinancing of the Company’s indebtedness with Hercules. NRG may also accelerate the maturity dates if it determines, in its sole discretion, that the Company is not making sufficient progress towards the completion of the construction of the 2.8 MW Tulare BioMAT project in California. If the Company is unable to make sufficient progress toward the completion of such project or to obtain another amendment, extension or refinancing, the Company may default on the NRG loan. The occurrence of an event of default under the NRG loan agreement may result in the principal and all accrued interest becoming immediately due and payable.

Under the most recent amendment to the loan agreement with Generate Lending, Generate Lending has a call right, which may be exercised during the period beginning on September 1, 2019 and ending on (and including) September 30, 2019 (which period may be further extended by mutual agreement of the parties), and which, if exercised, would require payment of all outstanding loans from Generate Lending (which are further described in Note 17. “Debt and Financing Obligations”) and all accrued and unpaid interest thereon on September 30, 2019. If Generate Lending calls the loan or determines to cease lending under its construction loan facility, the Company will be required to pursue alternative financing for the Company’s generation backlog. If the Company is unable to obtain such financing, it may result in delays in project execution and potential termination or events of default under certain power purchase agreements.

Finally, under the most recent amendment to the construction loan agreement with Fifth Third, the Company has agreed (among other things) that, no later than September 28, 2019, it will deliver to Fifth Third a binding loan agreement for permanent financing from another lender and one or more binding letters of intent from tax equity investors in an amount of at least $18.0 million, provided that such date will be automatically extended to October 21, 2019 in the event that the Hercules credit facility is repaid or extended beyond October 21, 2019, and further provided that both dates could be extended by an additional 60 days due to delays outside of the control of the Company or if Fifth Third is reasonably satisfied that the Company is negotiating diligently and in good faith with potential take-out lenders or tax equity investors. If the Company is unable to obtain a binding loan agreement for permanent financing from another lender and one or more binding letters of intent from tax equity investors in an amount of at least $18.0 million, and if Fifth Third does not provide further accommodation, the Company may default on the Fifth Third loan. The occurrence of an event of default under the Fifth Third loan may result in the principal and all accrued interest becoming immediately due and payable.

Should these obligations to NRG, Generate Lending and Fifth Third mature as described above without further extension or amendment, the Company may not have the liquidity to repay such obligations. The occurrence of an event of default under any of these project finance agreements also constitutes or may result in an event of default under, and causes or may cause the acceleration of amounts due under these agreements and a number of other material financial obligations of the Company, including the Hercules facility, the loan from the State of Connecticut, the financing agreements with PNC and the loan from the Connecticut Green Bank.

The terms of any financing and other measures to obtain funds that may be undertaken by the Company may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain and retain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development efforts and commercialization efforts and accelerate its exploration of potential sales of its intellectual property, other assets, and business, any of which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue its business plans, there is no assurance that the Company will be successful in obtaining and retaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. If the Company is unable to obtain external financing and/or increase liquidity through sales of its assets, its intellectual property or all or part of its business or through licensing of its technology and intellectual property, it may not be able to sustain future operations. As a result, the Company may be required to delay, reduce and/or cease its operations and/or seek bankruptcy protection. Based on its recurring losses from operations, expectation of continuing operating losses for the foreseeable future, negative working capital, and need to raise additional capital to finance its future operations, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year after the date of filing of this Quarterly Report on Form 10-Q.

The Company’s financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.

Use Of Estimates

Use of Estimates

The preparation of financial statements and related disclosures in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent liabilities. Estimates are used in accounting for, among other things, revenue recognition, contract loss accruals, excess, slow-moving and obsolete inventories, product warranty accruals, loss accruals on service agreements, share-based compensation expense, allowance for doubtful accounts, depreciation and amortization, impairment of goodwill and in-process research and development intangible assets, impairment of long-lived assets (including project assets), income taxes, contingencies and valuing assets acquired and pre-existing contractual arrangements settled in the acquisition of Bridgeport Fuel Cell, LLC. Estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the consolidated financial statements in the period they are determined to be necessary. Due to the inherent uncertainty involved in making estimates, actual results in future periods may differ from those estimates.