FuelCell Energy (FCEL) 10-Q 7 Jun 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Apr. 30, 2018	Jun. 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	FUELCELL ENERGY INC
Entity Central Index Key	886,128
Document Type	10-Q
Document Period End Date	Apr. 30, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	FCEL
Current Fiscal Year End Date	--10-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		85,964,710

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Current assets:
Cash and cash equivalents, unrestricted	$ 66,973	$ 49,294
Restricted cash and cash equivalents - short-term	5,249	4,628
Accounts receivable, net	46,189	68,521
Inventories	55,255	74,496
Other current assets	7,938	6,571
Total current assets	181,604	203,510
Restricted cash and cash equivalents - long-term	32,965	33,526
Project assets	79,595	73,001
Property, plant and equipment, net	44,667	43,565
Goodwill	4,075	4,075
Intangible asset	9,592	9,592
Other assets	15,121	16,517
Total assets	367,619	383,786
Current liabilities:
Current portion of long-term debt	10,094	28,281
Accounts payable	42,813	42,616
Accrued liabilities	14,731	18,381
Deferred revenue	9,424	7,964
Preferred stock obligation of subsidiary	837	836
Total current liabilities	77,899	98,078
Long-term deferred revenue	17,841	18,915
Long-term preferred stock obligation of subsidiary	14,825	14,221
Long-term debt and other liabilities	82,804	63,759
Total liabilities	193,369	194,973
Stockholders’ equity:
Common stock ($0.0001 par value); 225,000,000 and 125,000,000 shares authorized as of April 30, 2018 and October 31, 2017, respectively; 84,898,762 and 69,492,816 shares issued and outstanding as of April 30, 2018 and October 31, 2017, respectively	8	7
Additional paid-in capital	1,063,501	1,045,197
Accumulated deficit	(960,890)	(943,533)
Accumulated other comprehensive loss	(328)	(415)
Treasury stock, Common, at cost (182,962 and 88,861 shares as of April 30, 2018 and October 31, 2017, respectively)	(447)	(280)
Deferred compensation	447	280
Total stockholders’ equity	102,291	101,256
Total liabilities and stockholders' equity	367,619	383,786
Series B Preferred Stock [Member]
Current liabilities:
Redeemable preferred stock	59,857	59,857
Series C Preferred Stock [Member]
Current liabilities:
Redeemable preferred stock	$ 12,102	$ 27,700

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	225,000,000	125,000,000
Common stock, shares issued	84,898,762	69,492,816
Common stock, shares outstanding	84,898,762	69,492,816
Treasury stock, shares	182,962	88,861
Series B Preferred Stock [Member]
Preferred Stock, Liquidation Preference, Value	$ 64,020	$ 64,020
Series C Preferred Stock [Member]
Preferred Stock, Liquidation Preference, Value	$ 14,548	$ 33,300

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Revenues:
Product	$ 12,200	$ 737	$ 41,730	$ 2,544
Service and license	3,206	12,592	7,310	19,528
Generation	1,742	1,634	3,634	3,719
Advanced Technologies	3,682	5,454	6,769	11,628
Total revenues	20,830	20,417	59,443	37,419
Costs of revenues:
Product	13,947	3,204	40,084	7,259
Service and license	2,531	12,159	5,937	18,425
Generation	2,036	1,294	3,645	2,409
Advanced technologies	2,945	3,377	5,771	7,130
Total costs of revenues	21,459	20,034	55,437	35,223
Gross (loss) profit	(629)	383	4,006	2,196
Operating expenses:
Administrative and selling expenses	7,085	6,483	13,227	12,487
Research and development expenses	5,021	5,386	9,067	10,778
Restructuring expense		10		1,355
Total costs and expenses	12,106	11,879	22,294	24,620
Loss from operations	(12,735)	(11,496)	(18,288)	(22,424)
Interest expense	(2,059)	(2,310)	(4,200)	(4,577)
Other income, net	1,620	532	2,096	123
Loss before benefit (provision) for income taxes	(13,174)	(13,274)	(20,392)	(26,878)
Benefit (provision) for income taxes		36	3,035	(45)
Net loss	(13,174)	(13,238)	(17,357)	(26,923)
Net loss attributable to common stockholders	$ (18,173)	$ (14,038)	$ (26,619)	$ (28,523)
Loss per share basic and diluted:
Net loss per share attributable to common stockholders	$ (0.23)	$ (0.33)	$ (0.35)	$ (0.71)
Basic and diluted weighted average shares outstanding	79,563,265	42,568,818	75,731,565	40,049,948
Series C Preferred Stock [Member]
Operating expenses:
Series C preferred stock deemed dividends	$ (4,199)	$ 0	$ (7,662)	$ 0
Series B Preferred Stock [Member]
Operating expenses:
Series B preferred stock dividends	$ (800)	$ (800)	$ (1,600)	$ (1,600)

Consolidated Statements of Ope5

Consolidated Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Product	$ 12,200	$ 737	$ 41,730	$ 2,544
Service and license	3,206	12,592	7,310	19,528
Related Party [Member]
Product	10,900	200	11,400	300
Service and license	$ 600	$ 1,300	$ 1,800	$ 2,900

Statement of Comprehensive Loss

Statement of Comprehensive Loss Statement - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (13,174)	$ (13,238)	$ (17,357)	$ (26,923)
Foreign currency translation adjustments	54	32	87	(38)
Total comprehensive loss	$ (13,120)	$ (13,206)	$ (17,270)	$ (26,961)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2017
Cash flows from operating activities:
Net loss	$ (13,174)	$ (13,238)	$ (17,357)	$ (26,923)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation			1,378	2,226
Loss from change in fair value of embedded derivatives			45	25
Depreciation			4,302	4,296
Non-cash interest expense on preferred stock and debt obligations			2,845	2,958
Unrealized foreign exchange gains			(367)	(259)
Deferred income taxes			(3,035)	0
Project asset impairment			485	0
Other non-cash transactions, net			203	241
Decrease (increase) in operating assets:
Accounts receivable			24,379	(9,020)
Inventories			30,981	(1,779)
Other assets			(1,382)	(366)
Increase (decrease) in operating liabilities:
Accounts payable			3,290	(4,837)
Accrued liabilities			(4,238)	(5,684)
Deferred revenue			386	547
Net cash provided by (used in) operating activities			41,915	(38,575)
Cash flows from investing activities:
Capital expenditures			(5,506)	(8,290)
Project asset expenditures			(21,749)	(10,154)
Cash acquired from asset acquisition			0	633
Net cash used in investing activities			(27,255)	(17,811)
Cash flows from financing activities:
Repayment of debt			(10,919)	(6,299)
Proceeds from debt			13,091	17,891
Payment of deferred financing costs			(352)	(119)
Payment of preferred dividends and return of capital			(2,096)	(2,067)
Cash received for common stock issued for stock plans			0	50
Proceeds from sale of common stock and warrant exercises, net			3,268	12,785
Net cash provided by financing activities			2,992	22,241
Effects on cash from changes in foreign currency rates			87	(38)
Net increase (decrease) in cash, cash equivalents and restricted cash			17,739	(34,183)
Cash, cash equivalents and restricted cash-beginning of period			87,448	118,316	$ 118,316
Cash, cash equivalents and restricted cash-end of period	$ 105,187	$ 84,133	105,187	84,133	$ 87,448
Supplemental cash flow disclosures:
Cash interest paid			1,144	2,821
Noncash financing and investing activity:
Common stock issued for Employee Stock Purchase Plan in settlement of prior year accrued employee contributions			0	50
Net noncash reclass of project assets to inventory			11,740	0
Assumption of debt in conjunction with asset acquisition			0	2,289
Acquisition of project assets			0	2,386
Series C preferred share conversions			15,598	0
Accrued purchase of fixed assets, cash paid in subsequent period			273	1,816
Accrued purchase of project assets, cash paid in subsequent period			$ 1,504	$ 115

Nature of Business and Basis of

Nature of Business and Basis of Presentation	6 Months Ended
	Apr. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Note 1. Nature of Business and Basis of Presentation FuelCell Energy, Inc., together with its subsidiaries (the “Company”, “FuelCell Energy”, “we”, “us”, or “our”) is a leading integrated fuel cell company with a growing global presence. We design, manufacture, install, operate and service ultra-clean, efficient and reliable stationary fuel cell power plants. Our SureSource power plants generate electricity and usable high quality heat for commercial, industrial, government and utility customers. We have commercialized our stationary carbonate fuel cells and are also pursuing the complementary development of planar solid oxide fuel cells and other fuel cell technologies. Our operations are funded primarily through sales of equity instruments to strategic investors or in public markets, corporate and project level debt financing and local or state government loans or grants. In order to produce positive cash flow from operations, we need to be successful at increasing annual order volume and production and in our cost reduction efforts. 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 our financial position and results of operations as of and for the six months ended April 30, 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, 2017 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 our financial statements and notes thereto for the year ended October 31, 2017, which are contained in our 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. 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 assets and liabilities. Estimates are used in accounting for, among other things, revenue recognition, excess and obsolete inventories, product warranty costs, accruals for service agreements, allowance for uncollectible receivables, depreciation and amortization, impairment of goodwill, indefinite-lived intangible assets and long-lived assets, income taxes, and contingencies. 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. Related Parties POSCO Energy Co., Ltd. (“POSCO Energy”) is a related party and owned approximately 3.0% of the outstanding common shares of the Company as of April 30, 2018. Revenues from POSCO Energy for the three months ended April 30, 2018 and 2017 represent approximately 4.0% and 7.0%, respectively, of consolidated revenues and revenues from POSCO Energy for the six months ended April 30, 2018 and 2017 represent approximately 3.0% and 8.0%, respectively, of consolidated revenues. NRG Energy, Inc. (“NRG”) is a related party and owned approximately 2.0% of the outstanding common shares of the Company as of April 30, 2018. NRG Yield, Inc. (“NRG Yield”) is a dividend growth-oriented company formed by NRG that owns, operates and acquires a diversified portfolio of contracted renewable and conventional generation and thermal infrastructure assets in the United States. Revenues from NRG and NRG Yield for the three months ended April 30, 2018 and 2017 represent approximately 52.0% and 0.3%, respectively, of consolidated revenues and revenues for the six months ended April 30, 2018 and 2017 represent approximately 18.1% and 0.4%, respectively, of consolidated revenues.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	6 Months Ended
	Apr. 30, 2018
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	Note 2. Recent Accounting Pronouncements Recent Accounting Guidance Not Yet Effective In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” This ASU provides for five principles which should be followed to determine the appropriate amount and timing of revenue recognition for the transfer of goods and services to customers. The principles in this ASU should be applied to all contracts with customers regardless of industry. The amendments in this ASU were initially effective for fiscal years, and interim periods within those years, beginning after December 15, 2016, with two transition methods of adoption allowed. Early adoption for reporting periods prior to December 15, 2016 is not permitted. In March 2015, the FASB voted to defer the effective date by one year to fiscal years, and interim periods within those fiscal years beginning after December 15, 2017 (which, for the Company, will be the first quarter of fiscal year 2019), but allow adoption as of the original effective date. The Company has numerous different revenue sources including the sale and installation of fuel cell power plants, site engineering and construction services, sale of modules and spare parts, extended warranty service agreements, sale of electricity under power purchase agreements, license fees and royalty income from manufacturing and technology transfer agreements and customer-sponsored Advanced Technologies projects. This requires application of various revenue recognition methods under current accounting guidance. Although we anticipate that upon adoption of this new ASU the timing of revenue recognition for certain of our revenue sources might change, we are still evaluating the financial statement impacts of the guidance in this ASU and determining which transition method we will utilize. In May 2016, the FASB issued ASU 2016-12, “Revenue from Contracts with Customers (Topic 606).” This ASU provides narrow-scope improvements and practical expedients regarding collectability, presentation of sales tax collected from customers, non-cash consideration, contract modifications at transition, completed contracts at transition and other technical corrections. We have initiated a review of the contracts for our significant revenue streams to understand the impact of the adoption of this ASU. In February 2016, the FASB issued ASU 2016-02, “Leases” which, for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in its balance sheet. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, generally on a straight-line basis. This ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years (which, for the Company, will be the first quarter of fiscal year 2020). Early adoption is permitted. The Company has both operating and capital leases (refer to Note 17. “Commitments and Contingencies”) as well as sale-leasebacks accounted for under the finance method and may have other arrangements that contain embedded leases as characterized in this ASU. We expect that adoption of this ASU will result in the recognition of right-of-use assets and lease liabilities not currently recorded in our consolidated financial statements under existing accounting guidance. However, we are still evaluating all of the Company’s contractual arrangements and the impact that adoption of ASU 2016-02 will have on the Company’s consolidated financial statements.

Accounts Receivable, Net

Accounts Receivable, Net	6 Months Ended
	Apr. 30, 2018
Receivables [Abstract]
Accounts Receivable, Net	Note 3. Accounts Receivable, Net Accounts receivable as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Commercial Customers: Amount billed $ 15,621 $ 41,073 Unbilled recoverable costs (1) 22,746 18,162 38,367 59,235 Advanced Technologies (including U.S. government (2)): Amount billed 1,980 1,934 Unbilled recoverable costs 5,842 7,352 7,822 9,286 Accounts receivable, net $ 46,189 $ 68,521 (1) Additional long-term unbilled recoverable costs of $11.2 million and $12.8 million are included within “Other assets” as of April 30, 2018 and October 31, 2017, respectively. (2) Total U.S. government accounts receivable, including unbilled recoverable cost, outstanding as of April 30, 2018 and October 31, 2017 were $4.5 million and $3.2 million, respectively. We bill customers for power plant and power plant component sales based on certain contractual milestones being reached. We bill service agreements based on the contract price and billing terms of the contracts. Generally, our Advanced Technologies contracts are billed based on actual recoverable costs incurred, typically in the month subsequent to incurring costs. Some Advanced Technologies contracts are billed based on contractual milestones or costs incurred. Unbilled recoverable costs relate to revenue recognized on customer contracts that have not been billed. Accounts receivable are presented net of an allowance for doubtful accounts of $0.1 million as of April 30, 2018 and October 31, 2017. Uncollectible accounts receivable are charged against the allowance for doubtful accounts when all collection efforts have failed and it is deemed unlikely that the amount will be recovered. Accounts receivable from commercial customers (including unbilled recoverable costs) included amounts due from POSCO Energy of $12.2 million and $6.2 million as of April 30, 2018 and October 31, 2017, respectively, and amounts due from NRG and NRG Yield of $0.02 million and $0.1 million as of April 30, 2018 and October 31, 2017, respectively.

Inventories

Inventories	6 Months Ended
	Apr. 30, 2018
Inventory Disclosure [Abstract]
Inventories	Note 4. Inventories Inventories as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Raw materials $ 19,355 $ 20,065 Work-in-process (1) 35,900 54,431 Inventories $ 55,255 $ 74,496 (1) Work-in-process includes the standard components of inventory used to build the typical modules or module components that are intended to be used in future power plant orders or to service our service agreements. Included in work-in-process as of April 30, 2018 and October 31, 2017 was $29.3 million and $46.3 million, respectively, of completed standard components. Raw materials consist mainly of various nickel powders and steels, various other components used in producing cell stacks and purchased components for balance of plant. Work-in-process inventory is comprised of material, labor, and overhead costs incurred to build balance of plant components, fuel cell stacks and modules, which are subcomponents of a power plant.

Project Assets

Project Assets	6 Months Ended
	Apr. 30, 2018
Project Assets [Abstract]
Project Assets	Note 5. Project Assets Project assets as of April 30, 2018 and October 31, 2017 were $79.6 million and $73.0 million, respectively. Project assets as of April 30, 2018 and October 31, 2017 included five completed, commissioned installations generating power with respect to which we have a power purchase agreement (“PPA”) with the end-user of power and site host with an aggregate value of $31.1 million and $32.1 million as of April 30, 2018 and October 31, 2017, respectively. Certain of these assets are the subject of sale-leaseback arrangements with PNC Energy Capital, LLC (“PNC”), which are recorded under the financing method of accounting for a sale-leaseback. Under the financing method, the Company does not recognize the proceeds received from the lessor as a sale of such assets. The Project assets balance as of April 30, 2018 and October 31, 2017 also includes assets with an aggregate value of $48.5 million and $40.9 million, respectively, which are being developed and constructed by the Company and have not been placed in service. On April 5, 2018, the Company sold a project asset to NRG Yield which resulted in the recognition of product revenue of $10.8 million. The total reduction in project assets relating to the sale to NRG Yield was $9.8 million which was recorded as product cost of revenues. The Company also had a $0.5 million impairment of a project asset during the six months ended April 30, 2018 due to the termination of the project. The impairment was recorded as generation cost of revenues. Project construction costs incurred for the long-term project assets are reported as investing activities in the Consolidated Statements of Cash Flows. The proceeds received from the sale and subsequent leaseback of project assets are classified as “Cash flows from financing activities” within the Consolidated Statements of Cash Flows and are classified as a financing obligation within “Current portion of long-term debt” and “Long-term debt and other liabilities” on the Consolidated Balance Sheets (refer to Note 14 for more information).

Other Current Assets

Other Current Assets	6 Months Ended
	Apr. 30, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Other Current Assets	Note 6. Other Current Assets Other current assets as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Advance payments to vendors (1) $ 2,714 $ 1,035 Deferred finance costs (2) 129 129 Prepaid expenses and other (3) 5,095 5,407 Other current assets $ 7,938 $ 6,571 (1) Advance payments to vendors relate to payments for inventory purchases ahead of receipt. (2) Represents the current portion of direct deferred finance costs that relate primarily to securing the $40.0 million loan facility with NRG which is being amortized over the five-year life of the facility. (3) Primarily relates to other prepaid expenses including insurance, rent and lease payments.

Other Assets

Other Assets	6 Months Ended
	Apr. 30, 2018
Other Assets Noncurrent [Abstract]
Other Assets	Note 7. Other Assets Other assets as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Long-term stack residual value (1) $ 1,096 $ 987 Deferred finance costs (2) 32 97 Long-term unbilled recoverable costs (3) 11,153 12,806 Other (4) 2,840 2,627 Other assets $ 15,121 $ 16,517 (1) Relates to estimated residual value for module exchanges performed under the Company’s service agreements where the useful life extends beyond the contractual term of the service agreement and the Company obtains title to the module from the customer upon expiration or termination of the service agreement. If the Company does not obtain rights to title from the customer, the full cost of the module is expensed at the time of the module exchange. (2) Represents the long-term portion of direct deferred finance costs relating to the Company’s loan facility with NRG which is being amortized over the five-year life of the facility. (3) Represents unbilled recoverable costs that relate to revenue recognized on customer contracts that will be billed in future periods in excess of twelve months from the balance sheet date. (4) The Company entered into an agreement with one of its customers on June 29, 2016 which includes a fee for the purchase of the plants at the end of the term of the agreement. The fee is payable in installments over the term of the agreement and the total paid as of April 30, 2018 and October 31, 2017 was $2.0 million and $1.6 million, respectively. Also included within “Other” are long-term security deposits.

Accounts Payable

Accounts Payable	6 Months Ended
	Apr. 30, 2018
Accounts Payable Current [Abstract]
Accounts Payable	Note 8. Accounts Payable Accounts payable as of April 30, 2018 and October 31, 2017 was $42.8 million and $42.6 million, respectively. Included in the balance were amounts due to POSCO Energy of $32.7 million as of April 30, 2018 and October 31, 2017 for the purchase of inventory.

Accrued Liabilities

Accrued Liabilities	6 Months Ended
	Apr. 30, 2018
Accrued Liabilities Current [Abstract]
Accrued Liabilities	Note 9. Accrued Liabilities Accrued liabilities as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Accrued payroll and employee benefits $ 3,124 $ 5,315 Accrued contract loss — 37 Accrued product warranty cost (1) 343 348 Accrued material purchases (2) 548 2,396 Accrued service agreement costs (3) 1,726 3,319 Contractual milestone billings for inventory (4) 5,921 4,440 Accrued legal, taxes, professional and other 3,069 2,526 Accrued liabilities $ 14,731 $ 18,381 (1) Activity in the accrued product warranty costs for the six months ended April 30, 2018 included additions for estimates of future warranty obligations of $0.3 million on contracts in the warranty period and reductions related to actual warranty spend of $0.3 million as contracts progress through the warranty period or are beyond the warranty period. (2) The Company acts as a procurement agent for POSCO Energy under an Integrated Global Supply Chain Agreement whereby the Company procures materials on POSCO Energy’s behalf for its Korean production facility. This liability represents amounts received for the purchase of materials on behalf of POSCO Energy. Amounts due to vendors is recorded as “Accounts payable.” (3) The loss accruals on service contracts were $1.1 million as of October 31, 2017 which decreased to $1.0 million as of April 30, 2018. The accruals for performance guarantees decreased from $2.2 million as of October 31, 2017 to $0.7 million as of April 30, 2018 resulting from payments offset by additional accruals for the minimum power output falling below the contract requirements for certain service agreements. (4) Amounts represent contractual milestone billings for inventory that will be provided to POSCO Energy within the next twelve months under a transaction that will not result in revenue recognition.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Apr. 30, 2018
Equity [Abstract]
Stockholders' Equity	Note 10. Stockholders’ Equity Changes in stockholders’ equity Changes in stockholders’ equity were as follows for the six months ended April 30, 2018: Total Stockholders’ Equity Balance as of October 31, 2017 $ 101,256 Share-based compensation 1,378 Proceeds from common stock issuance and warrant exercises, net of fees 3,268 Common stock issued, non-employee compensation 282 Taxes paid upon vesting of restricted stock awards, net of stock issued under benefit plans (621 ) Preferred dividends – Series B (1,600 ) Conversion of Redeemable Series C preferred stock 15,598 Other comprehensive income - foreign currency translation adjustments 87 Net loss (17,357 ) Balance as of April 30, 2018 $ 102,291 Authorized Common Stock On December 14, 2017, the number of authorized shares of the Company’s common stock was increased from 125,000,000 to 225,000,000, by a vote of the holders of a majority of the outstanding shares of the Company’s common stock. NASDAQ Marketplace Rule 5635(d) On December 14, 2017, in accordance with NASDAQ Marketplace Rule 5635(d), the Company’s common stockholders approved the issuance of shares of the Company’s common stock exceeding 19.9% of the number of shares outstanding on September 5, 2017, upon the conversion and/or redemption of the Series C Convertible Preferred Stock issued in an underwritten offering in September 2017. Public Offerings and Outstanding Warrants On May 3, 2017, the Company completed an underwritten public offering of (i) 12,000,000 shares of its common stock, (ii) Series C warrants to purchase 12,000,000 shares of its common stock and (iii) Series D warrants to purchase 12,000,000 shares of its common stock. The Series C warrants have an exercise price of $1.60 per share and a term of five years. A total of 11,536 shares of common stock were issued during the first six months of fiscal year 2018 upon exercise of Series C warrants and the Company received total proceeds of $0.02 million in connection with such exercises. The Series D warrants have an exercise price of $1.28 per share and a term of one year. A total of 2,584,174 shares of common stock were issued during the first six months of fiscal year 2018 upon the exercise of Series D warrants and the Company received total proceeds of $3.3 million in connection with such exercises. As of April 30, 2018, all Series D warrants have been exercised. On July 12, 2016, the Company closed on a registered public offering of securities to a single institutional investor pursuant to a placement agent agreement with J.P. Morgan Securities LLC. In conjunction with the offering, the Company issued 7,680,000 Series A Warrants, all of which remained outstanding as of April 30, 2018, at an exercise price of $5.83 per share. The following table summarizes outstanding warrant activity during the six months ended April 30, 2018: Series A Warrants Series C Warrants Series D Warrants Balance as of October 31, 2017 7,680,000 11,580,900 2,584,174 Warrants exercised — (11,536 ) (2,584,174 ) Warrants expired — — — Balance as of April 30, 2018 7,680,000 11,569,364 —

Redeemable Preferred Stock

Redeemable Preferred Stock	6 Months Ended
	Apr. 30, 2018
Preferred Stock [Abstract]
Redeemable Preferred Stock	Note 11. Redeemable Preferred Stock The Company is authorized to issue up to 250,000 shares of preferred stock, par value $0.01 per share, issuable in one or more series. Of these authorized shares, the Company had, as of April 30, 2018, issued and outstanding shares of Series C Convertible Preferred Stock and 5% Series B Cumulative Convertible Perpetual Preferred Stock in the amounts described below. Series C Preferred Stock The Company issued an aggregate of 33,500 shares of its Series C Convertible Preferred Stock (“Series C Preferred Stock” and such shares, the “Series C Preferred Shares”), $0.01 par value and $1,000 stated value per share, during the fiscal year ended October 31, 2017. As of April 30, 2018 and October 31, 2017, there were 14,548 and 33,300 shares of Series C Preferred Stock issued and outstanding, respectively, with a carrying value of $12.1 million and $27.7 million, respectively. During the six months ended April 30, 2018, holders of our Series C Preferred Stock converted 18,752 shares of the Series C Preferred Stock into common shares through installment conversions resulting in a reduction of $15.6 million to the carrying value being recorded to equity. Installment conversions in which the conversion price is below the fixed conversion price of $1.84 per share The deemed dividend represents the difference between the fair value of the common shares issued to settle the installment amounts and the carrying value of the Series C Preferred Shares. Based on review of pertinent accounting literature including Accounting Standards Codification (“ASC”) 470 – Debt - Distinguishing Liabilities from Equity Derivative and Hedging A summary of certain terms of the Series C Preferred Stock are described as follows: Conversion Rights. The Series C Preferred Shares are convertible into shares of common stock subject to the beneficial ownership limitations provided in the Certificate of Designations for Series C Preferred Stock (the “Certificate of Designations”), at a conversion price equal to $1.84 per share of common stock (“Conversion Price”), subject to adjustment as provided in the Certificate of Designations, at any time at the option of the holder. In the event of a triggering event, as defined in the Certificate of Designations, the Series C Preferred Shares are convertible into shares of common stock at a conversion price of the lower of $1.84 per share and 85% of the lowest volume weighted average price (“VWAP”) of the common stock of the five trading days immediately prior to delivery of the applicable conversion notice. The holders will be prohibited from converting Series C Preferred Shares into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would own more than 8.99% of the total number of shares of common stock then issued and outstanding. Each holder has the right to increase its maximum percentage up to 9.99% upon 60 days’ notice to the Company. Installment Payments. On November 1, 2017 and on the sixteenth day and first day of each calendar month thereafter until March 1, 2019, subject to extension in certain circumstances (the “Maturity Date”), inclusive, the Company will redeem the stated value of Series C Preferred Shares in thirty-three equal installments of $1.0 million (each bimonthly amount, an “Installment Amount” and the date of each such payment, an “Installment Date”). The holders will have the ability to defer installment payments, but not beyond the Maturity Date. In addition, during each period commencing on the 11th trading day prior to an Installment Date and prior to the immediately subsequent Installment Date, the holders may elect to accelerate the conversion of Series C Preferred Shares at the then applicable installment conversion price, provided that the holders may not elect to effect any such acceleration during such installment period if either (a) in the aggregate, all the accelerations in such installment period exceed the sum of three other Installment Amounts, or (b) the number of Series C Preferred Shares subject to prior accelerations exceeds in the aggregate twelve Installment Amounts. Subject to certain conditions as provided in the Certificate of Designations, the Company may elect to pay the Installment Amounts in cash or shares of common stock or in a combination of cash and shares of common stock. Installment Amounts paid in shares will be that number of shares of common stock equal to (a) the applicable Installment Amount, to be paid in common stock divided by (b) the least of (i) the then existing conversion price, (ii) 87.5% of the VWAP of the common stock on the trading day immediately prior to the applicable Installment Date, and (iii) 87.5% of the arithmetic average of the two lowest VWAPs of the common stock during the ten consecutive trading day period ending and including the trading day immediately prior to the applicable Installment Date as applicable, provided that the Company meets standard equity conditions. The Company shall make such election no later than the eleventh trading day immediately prior to the applicable Installment Date. If the Company elects or is required to pay an Installment Amount in whole or in part in cash, the amount paid will be equal to 108% of the applicable Installment Amount. Dividends. Each holder of the Series C Preferred Shares shall be entitled to receive dividends (a) if no triggering event, as defined in the Certificate of Designations, has occurred and is continuing when and as declared by the Board of Directors, in its sole and absolute discretion or (b) if a triggering event has occurred and until such triggering event has been cured, a dividend of 15% per annum based on the holder’s outstanding number of Series C Preferred Shares multiplied by the stated value. There were no triggering events or dividends declared in fiscal year 2017 or during the six months ended April 30, 2018. Redemption. In the event of a triggering event, as defined in the Certificate of Designations, the holders of the Series C Preferred Shares can force redemption at a price equal to the greater of (a) the conversion amount to be redeemed multiplied by 125% and (b) the product of (i) the conversion rate with respect to the conversion amount in effect at such time as such holder delivers a triggering event redemption notice multiplied by (ii) the greatest closing sale price of the common stock on any trading day during the period commencing on the date immediately preceding such triggering event and ending on the date the Company makes the entire payment required. Liquidation. In the event of the Company’s liquidation, dissolution, or winding up, prior to distribution to holders of securities ranking junior to the Series C Preferred Shares, holders of Series C Preferred Shares will be entitled to receive the amount of cash, securities or other property equal to the greater of (a) the stated value thereof on the date of such payment plus accrued dividends, if any and (b) the amount per share such holder would receive if such holder converted such Series C Preferred Shares into common stock immediately prior to the date of such payment. Ranking and Voting Rights. Shares of Series C Preferred Stock rank with respect to dividend rights and rights upon the Company’s liquidation, winding up or dissolution: • senior to shares of our common stock; • junior to our debt obligations; • junior to our outstanding Series B Preferred Stock; and • effectively junior to our subsidiaries’ (i) existing and future liabilities and (ii) capital stock held by others. The holders of the Series C Preferred Shares have no voting rights, except as required by law. Any amendment to the Company’s certificate of incorporation or bylaws or the Certificate of Designations that adversely affects the powers, preferences and rights of the Series C Preferred Shares requires the approval of the holders of a majority of the Series C Preferred Shares then outstanding. Redeemable Series B Preferred Stock We have 105,875 shares of our 5% Series B Cumulative Convertible Perpetual Preferred Stock (Liquidation Preference $1,000.00 per share) (“Series B Preferred Stock”) authorized for issuance. As of April 30, 2018 and October 31, 2017, there were 64,020 shares of Series B Preferred Stock issued and outstanding, with a carrying value of $59.9 million. Dividends of $1.6 million were paid in cash for each of the six month periods ended April 30, 2018 and 2017, respectively. Class A Cumulative Redeemable Exchangeable Preferred Shares FCE FuelCell Energy Ltd. (“FCE Ltd”), a subsidiary of the Company, has 1,000,000 Class A Cumulative Redeemable Exchangeable Preferred Shares (the “Series 1 Preferred Shares”) outstanding, which are held by Enbridge, Inc. (“Enbridge”), which is a related party. The Company made its scheduled payments of Cdn. $0.5 million during each of the six month periods ended April 30, 2018 and 2017 under the terms of the Company’s agreement with Enbridge. The Company also recorded interest expense, which reflects the amortization of the fair value discount of approximately Cdn. $1.4 million and Cdn. $1.3 million for the six months ended April 30, 2018 and 2017, respectively. As of April 30, 2018 and October 31, 2017, the carrying value of the Series 1 Preferred Shares was Cdn. $20.1 million (U.S. $15.7 million) and Cdn. $19.4 million (U.S. $15.1 million), respectively, and is classified as a preferred stock obligation of a subsidiary on the Consolidated Balance Sheets.

Loss Per Share

Loss Per Share	6 Months Ended
	Apr. 30, 2018
Earnings Per Share [Abstract]
Loss Per Share	Note 12. Loss Per Share The calculation of basic and diluted loss per share was as follows: Three Months Ended April 30, Six Months Ended April 30, 2018 2017 2018 2017 Numerator Net loss $ (13,174 ) $ (13,238 ) $ (17,357 ) $ (26,923 ) Series C preferred stock deemed dividends (4,199 ) — (7,662 ) — Series B preferred stock dividends (800 ) (800 ) (1,600 ) (1,600 ) Net loss attributable to common stockholders $ (18,173 ) $ (14,038 ) $ (26,619 ) $ (28,523 ) Denominator Weighted average basic common shares 79,563,265 42,568,818 75,731,565 40,049,948 Effect of dilutive securities (1) — — — — Weighted average diluted common shares 79,563,265 42,568,818 75,731,565 40,049,948 Basic loss per share $ (0.23 ) $ (0.33 ) $ (0.35 ) $ (0.71 ) Diluted loss per share (1) $ (0.23 ) $ (0.33 ) $ (0.35 ) $ (0.71 ) (1) Due to the net loss to common stockholders in each of the periods presented above, diluted loss per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive. As of April 30, 2018 and 2017, potentially dilutive securities excluded from the diluted loss per share calculation are as follows: April 30, April 30, 2018 2017 May 2017 Offering - Series C Warrants 11,569,364 — July 2016 Offering - Series A Warrants 7,680,000 7,680,000 July 2014 Offering - NRG Warrant — 166,666 Outstanding options to purchase common stock 327,890 214,383 Unvested Restricted Stock Awards 1,185,457 1,986,732 Series C Preferred Shares to satisfy conversion requirements (1) 7,906,783 — 5% Series B Cumulative Convertible Preferred Stock 454,043 454,043 Series 1 Preferred Shares to satisfy conversion requirements 15,166 15,166 Total potentially dilutive securities 29,138,703 10,516,990 (1) The number of shares of common stock issuable upon conversion of the Series C Preferred Stock was calculated using the stated value outstanding on April 30, 2018 of $14.5 million (original stated value of $33.5 million less the stated value of conversions to date through April 30, 2018 totaling $19.0 million) divided by the conversion price of $1.84. The actual number of shares issued could vary depending on the actual market price of the Company’s common shares on the date of such conversions.

Restricted Cash

Restricted Cash	6 Months Ended
	Apr. 30, 2018
Restricted Cash And Investments [Abstract]
Restricted Cash	Note 13. Restricted Cash As of April 30, 2018 and October 31, 2017, there was $38.2 million of restricted cash and cash equivalents pledged as collateral for letters of credit for certain banking requirements and contractual commitments. The restricted cash balance for both periods presented includes $15.0 million which has been placed in a Grantor’s Trust account to secure certain obligations under a 15-year service agreement and has been classified as long-term. The restricted cash balance as of April 30, 2018 and October 31, 2017 also includes $17.2 million and $17.0 million, respectively, to support obligations related to PNC sale-leaseback transactions. As of April 30, 2018 and October 31, 2017, outstanding letters of credit totaled $2.3 million and $2.9 million, respectively. These expire on various dates through April 2019.

Debt and Financing Obligation

Debt and Financing Obligation	6 Months Ended
	Apr. 30, 2018
Debt [Abstract]
Debt and Financing Obligation	Note 14. Debt and Financing Obligation Debt as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Connecticut Development Authority Note $ 2,256 $ 2,349 Connecticut Green Bank Note 6,051 6,052 Financing obligation for sale-leaseback transactions 46,110 46,937 State of Connecticut Loan 10,000 10,000 Hercules Loan and Security Agreement 26,754 21,468 New Britain Renewable Energy Term Loan 1,402 1,697 Equipment financing and capital lease obligations 489 632 Deferred finance costs (1,455 ) (1,344 ) Total debt $ 91,607 $ 87,791 Current portion of long-term debt and financing obligation (10,094 ) (28,281 ) Long-term debt $ 81,513 $ 59,510 The Company has a loan agreement with the Connecticut Development Authority that was used to finance equipment purchases associated with our prior manufacturing capacity expansion. The interest rate is 5.0 percent per annum and the loan is collateralized by the assets procured under this loan as well as $4.0 million of additional machinery and equipment. The original repayment terms required monthly interest and principal payments through May 2018. However, the repayment terms for the loan agreement with the Connecticut Development Authority were modified in April 2018, such that the remaining balance and interest will be paid on a monthly basis through December 2018. The Company has a long-term loan agreement with the Clean Energy Finance and Investment Authority, now known as the Connecticut Green Bank, totaling $5.9 million in support of the Bridgeport Fuel Cell Park project. The loan agreement carries an interest rate of 5.0 percent per annum. Interest only payments commenced in January 2014 and principal payments will commence on the eighth anniversary of the project’s provisional acceptance date, which is December 20, 2021, payable in forty-eight equal monthly installments. Outstanding amounts are secured by future cash flows from the Bridgeport Fuel Cell Park service agreement. In 2015, the Company entered into the first of a series of agreements with PNC, whereby the Company’s project finance subsidiaries entered into sale-leaseback agreements for commissioned projects where we had entered into a PPA with the site host/end-user of produced power. Under the financing method of accounting for a sale-leaseback, the Company does not recognize as income any of the sale proceeds received from the lessor that contractually constitute payment to acquire the assets subject to these arrangements. Instead, the sale proceeds received are accounted for as financing obligations. The outstanding financing obligation balance as of April 30, 2018 was $46.1 million and the decrease from $46.9 million on October 31, 2017 includes lease payments offset by the recognition of interest expense. The sale-leaseback transactions include a fair value purchase option at the end of the lease term. In November 2015, the Company closed on a definitive Assistance Agreement with the State of Connecticut and received a disbursement of $10.0 million for the first phase of an expansion project to expand the existing 65,000 square foot manufacturing facility in Torrington, Connecticut by approximately 102,000 square feet for a total size of 167,000 square feet. In conjunction with this financing, the Company entered into a $10.0 million Promissory Note and related security agreement securing the loan with equipment liens and a mortgage on its Danbury, Connecticut location. Pursuant to the terms of the loan, principal payments were deferred for the first four years and will begin in November 2019. Monthly interest payments at a fixed rate of 2.0 percent per annum began in December 2015. The financing is payable over 15 years and is predicated on certain terms and conditions, including the forgiveness of up to half of the loan principal if certain job retention and job creation targets are reached. On April 17, 2017, the Company entered into an amendment to the Assistance Agreement extending certain job creation target dates until October 28, 2019. In April 2016, the Company entered into a loan and security agreement (the “Hercules Agreement”) with Hercules Capital, Inc. (“Hercules”) subject to certain terms and conditions of which the Company drew down $20.0 million during fiscal year 2016. The loan was a 30 month secured facility. The term loan interest rate was 9.75 percent per annum as of October 31, 2017 and increased to 10.0 percent per annum as of January 31, 2018 as a result of the increase in the prime rate. In addition to interest, which is paid on a monthly basis, principal payments commenced on November 1, 2017 in equal monthly installments. The loan balance and all accrued and unpaid interest was due and payable by October 1, 2018. Under the terms of the Hercules Agreement, there was an end of term charge of $1.7 million due on October 31, 2018, which was being accreted over the 30 month term using the effective interest rate method. On March 28, 2018, the Company and Hercules entered into an amendment to the Hercules Agreement (such amendment, the “Amendment”) which allowed the Company to draw a term loan advance of $13.1 million. The aggregate amount outstanding, which includes the amount outstanding under the original Hercules Agreement of $11.9 million and the term loan advance under the Amendment, is $25.0 million. The term loan maturity date is October 1, 2020, subject to extension upon the Company’s achievement of certain performance milestones. Payments for the aggregate amount outstanding are interest-only for the initial 12-month period, followed by equal monthly installments of principal and interest until the term loan maturity date. The term loan interest rate is 10.15% per annum. The end of term charge of $1.7 million remains due on October 31, 2018, however, under the terms of the Amendment, it has been considered earned and has been fully accrued. An additional end of term charge of $0.9 million will be due on October 1, 2020, subject to extension upon the Company’s achievement of certain performance milestones. The end of term charge is being accreted over a 30-month term. As collateral for obligations under the Hercules Agreement, as amended, the Company granted Hercules a security interest in FuelCell Energy, Inc.’s existing and thereafter-acquired assets except for intellectual property and certain other excluded assets. The collateral does not include assets held by FuelCell Energy Finance, LLC (“FuelCell Finance”) or any project subsidiary thereof. The Company may continue to collateralize and finance its project subsidiaries through other lenders and partners. Under the Hercules Agreement, as amended, there is a minimum cash covenant which requires the Company to maintain an unrestricted cash balance in accounts subject to an account control agreement in favor of Hercules of at least the greater of (x) (a) 75% of the outstanding loan balance plus (b) the amount of accounts payable (as defined under GAAP) not paid within 90 days of the invoice date and (y) $10.0 million. The Hercules Agreement, as amended, contains customary representations and warranties, affirmative and negative covenants, and events of default that entitle Hercules to cause our indebtedness under the agreement to become immediately due and payable. In November 2016, we assumed debt with Webster Bank in the amount of $2.3 million as a part of an asset acquisition transaction. The term loan interest rate is 5.0 percent per annum and payments, which commenced in January 2017, are due on a quarterly basis. The balance outstanding as of April 30, 2018 was $1.4 million. The Company leases computer equipment under master lease agreements. Lease payment terms are generally thirty-six months from the date of acceptance for leased equipment. Deferred finance costs relate primarily to sale-leaseback transactions entered into with PNC which are being amortized over the ten-year term and direct deferred finance costs relating to the Hercules Agreement, as amended, which is being amortized over the 30 month life of the loan. In July 2014, the Company, through its wholly-owned subsidiary, FuelCell Finance, entered into a Loan Agreement with NRG (the “NRG Agreement”). Pursuant to the NRG Agreement, NRG has extended a $40.0 million revolving construction and term financing facility for the purpose of accelerating project development by the Company and its subsidiaries. We may draw on the facility to finance the construction of projects through the commercial operating date of the power plants so financed. The interest rate is 8.5 percent per annum for construction-period financing and 8.0 percent per annum thereafter. Fees that were paid by FuelCell Finance to NRG for making the loan facility available and related legal fees incurred were capitalized and are being amortized straight-line over the life of the related loan agreement, which is five years. The term of the loans are up to five years but may be repaid early should the projects be sold or refinanced at the option of the Company. There were no drawdowns or outstanding balances on the NRG Agreement as of April 30, 2018 and October 31, 2017.

Benefit Plans

Benefit Plans	6 Months Ended
	Apr. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Benefit Plans	Note 15. Benefit Plans 2018 Omnibus Incentive Plan The Company’s 2018 Omnibus Incentive Plan (the “2018 Incentive Plan”) was approved by the Company’s stockholders at the 2018 Annual Meeting of Stockholders, which was held on April 5, 2018. The 2018 Incentive Plan provides that a total of 4.0 million shares of the Company’s common stock may be issued thereunder. The 2018 Incentive Plan authorizes grants of stock options, stock appreciation rights, restricted stock awards (“RSAs”), restricted stock units (“RSUs”), performance shares, performance units and incentive awards to key employees, directors, consultants and advisors. Previous equity awards which remain outstanding under the 2006 and 2010 Equity Incentive Plans as of April 30, 2018 consisted of incentive stock options, nonstatutory stock options, RSAs and RSUs. Restricted Stock Awards and Units A total of 2.2 million shares were granted as RSUs under the 2018 Incentive Plan during the six months ended April 30, 2018. These RSUs were awarded to the Company’s executive officers and key employees. RSU expense is based on the fair value of the award at the date of grant and is amortized over the vesting period which is either over three or four years. There were 4.3 million RSUs and RSAs outstanding as of April 30, 2018 under the 2018 Incentive Plan and the Company’s previous incentive plans. Stock Awards During the six months ended April 30, 2018, the Company awarded 158,708 shares of fully vested, unrestricted common stock to the independent members of our board of directors as a component of board of director compensation, which will result in recognition of $0.3 million of expense (recognized ratably over the next 12 months). Employee Stock Purchase Plan The 2018 Employee Stock Purchase Plan (the “ESPP”) was approved by the Company’s stockholders at the 2018 Annual Meeting of Stockholders. The adoption of the ESPP allows the Company to provide eligible employees of the Company and of certain designated subsidiaries with the opportunity to voluntarily participate in the ESPP, enabling such participants to purchase shares of the Company’s common stock at a discount to market price at the time of such purchase. The maximum number of the Company’s shares of common stock that may be issued under the ESPP is 500,000 shares.

Income Taxes

Income Taxes	6 Months Ended
	Apr. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Note 16. Income Taxes The Company recorded an income tax benefit totaling $3.0 million for the six months ended April 30, 2018 compared to income tax expense of $0.05 million for the six months ended April 30, 2017. The income tax benefit for the six months ended April 30, 2018 related to the Tax Cuts and Jobs Act (the “Act”) that was enacted on December 22, 2017. The Act reduced the U.S. federal corporate tax rate from 34% to 21% effective January 1, 2018 which resulted in a deferred tax benefit of $1.0 million related to a reduction of the Company’s deferred tax liability for in process research and development (“IPR&D”). The Act also established an unlimited carryforward period for the net operating loss (“NOL”) the Company anticipates generating in fiscal year 2018. This provision of the Act resulted in a reduction of the valuation allowance attributable to deferred tax assets at the enactment date by $2.0 million based on the indefinite life of the resulting NOL as well as the deferred tax liability for IPR&D.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Apr. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 17. Commitments and Contingencies Lease Agreements As of April 30, 2018 and October 31, 2017, the Company had equipment financing and capital lease obligations of $0.5 million and $0.6 million, respectively. Payment terms are generally thirty-six months from the date of acceptance for leased equipment. The Company also leases certain computer and office equipment and manufacturing facilities in Torrington and Danbury, Connecticut under operating leases expiring on various dates through 2030. Non-cancelable minimum payments applicable to operating and capital leases as of April 30, 2018 were as follows: Operating Leases Capital Leases Due Year 1 $ 685 $ 300 Due Year 2 502 146 Due Year 3 367 36 Due Year 4 382 5 Due Year 5 376 2 Thereafter 3,190 — Total $ 5,502 $ 489 Service Agreements Under the provisions of our service agreements, we provide services to maintain, monitor, and repair customer power plants to meet minimum operating levels. Under the terms of our service agreements, the particular power plant must meet a minimum operating output during defined periods of the term. If minimum output falls below the contract requirement, we may be subject to performance penalties and/or may be required to repair or replace the customer’s fuel cell module(s). An estimate is not recorded for a potential performance guarantee liability until a performance issue has occurred at a particular power plant. At that point, the actual power plant’s output is compared against the minimum output guarantee and an accrual is recorded. The review of power plant performance is updated for each reporting period to incorporate the most recent performance of the power plant and minimum output guarantee payments made to customers, if any. The Company has provided for an accrual for performance guarantees, based on actual fleet performance, which totaled $0.7 million and $2.2 million as of April 30, 2018 and October 31, 2017, respectively, and is recorded in “Accrued liabilities.” Our loss accrual on service agreements totaled $1.0 million and $1.1 million as of April 30, 2018 and October 31, 2017, respectively, and is recorded in “Accrued liabilities.” Our accrual estimates are performed on a contract by contract basis and include cost assumptions based on what we anticipate the service requirements will be to fulfill obligations under each contract. Power Purchase Agreements Under the terms of our PPAs, customers agree to purchase power from our fuel cell power plants at negotiated rates. Electricity rates are generally a function of the customers’ current and future electricity pricing available from the grid. As owner or lessee of the power plants, we are responsible for all operating costs necessary to maintain, monitor and repair the power plants. Under certain agreements, we are also responsible for procuring fuel, generally natural gas or biogas, to run the power plants. Other As of April 30, 2018, the Company had unconditional purchase commitments aggregating $48.1 million, for materials, supplies and services in the normal course of business. Under certain sales and financing agreements, the Company is contractually committed to provide compensation for any losses that our customers and finance partners may suffer in certain limited circumstances resulting from reductions in realization of the U.S. Investment Tax Credit. Such obligations would arise as a result of reductions to the value of the underlying fuel cell projects as assessed by the U.S. Internal Revenue Service (the “IRS”). The Company does not believe that any payments under these contracts are probable based on the facts known at the reporting date. The maximum potential future payments that the Company could have to make with respect to these obligations would depend on the difference between the fair values of the fuel cell projects sold or financed and the values the IRS would determine as the fair value for the systems for purposes of claiming the Investment Tax Credit. The value of the Investment Tax Credit in the Company’s agreements is based on guidelines provided by the regulations from the IRS. The Company and its customers use fair values determined with the assistance of independent third-party appraisals. We are involved in legal proceedings, claims and litigation arising out of the ordinary conduct of our business. Although we cannot assure the outcome, management presently believes that the result of such legal proceedings, either individually, or in the aggregate, will not have a material adverse effect on our consolidated financial statements, and no material amounts have been accrued in our consolidated financial statements with respect to these matters.

Nature of Business and Basis 25

Nature of Business and Basis of Presentation (Policies)	6 Months Ended
	Apr. 30, 2018
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 our financial position and results of operations as of and for the six months ended April 30, 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, 2017 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 our financial statements and notes thereto for the year ended October 31, 2017, which are contained in our 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.
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 assets and liabilities. Estimates are used in accounting for, among other things, revenue recognition, excess and obsolete inventories, product warranty costs, accruals for service agreements, allowance for uncollectible receivables, depreciation and amortization, impairment of goodwill, indefinite-lived intangible assets and long-lived assets, income taxes, and contingencies. 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.
Related Parties	Related Parties POSCO Energy Co., Ltd. (“POSCO Energy”) is a related party and owned approximately 3.0% of the outstanding common shares of the Company as of April 30, 2018. Revenues from POSCO Energy for the three months ended April 30, 2018 and 2017 represent approximately 4.0% and 7.0%, respectively, of consolidated revenues and revenues from POSCO Energy for the six months ended April 30, 2018 and 2017 represent approximately 3.0% and 8.0%, respectively, of consolidated revenues. NRG Energy, Inc. (“NRG”) is a related party and owned approximately 2.0% of the outstanding common shares of the Company as of April 30, 2018. NRG Yield, Inc. (“NRG Yield”) is a dividend growth-oriented company formed by NRG that owns, operates and acquires a diversified portfolio of contracted renewable and conventional generation and thermal infrastructure assets in the United States. Revenues from NRG and NRG Yield for the three months ended April 30, 2018 and 2017 represent approximately 52.0% and 0.3%, respectively, of consolidated revenues and revenues for the six months ended April 30, 2018 and 2017 represent approximately 18.1% and 0.4%, respectively, of consolidated revenues.
Accounts Receivable, Net	Accounts Receivable, Net We bill customers for power plant and power plant component sales based on certain contractual milestones being reached. We bill service agreements based on the contract price and billing terms of the contracts. Generally, our Advanced Technologies contracts are billed based on actual recoverable costs incurred, typically in the month subsequent to incurring costs. Some Advanced Technologies contracts are billed based on contractual milestones or costs incurred. Unbilled recoverable costs relate to revenue recognized on customer contracts that have not been billed.
Inventories	Inventories Raw materials consist mainly of various nickel powders and steels, various other components used in producing cell stacks and purchased components for balance of plant. Work-in-process inventory is comprised of material, labor, and overhead costs incurred to build balance of plant components, fuel cell stacks and modules, which are subcomponents of a power plant.

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	6 Months Ended
	Apr. 30, 2018
Receivables [Abstract]
Schedule of Accounts Receivable	Accounts receivable as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Commercial Customers: Amount billed $ 15,621 $ 41,073 Unbilled recoverable costs (1) 22,746 18,162 38,367 59,235 Advanced Technologies (including U.S. government (2)): Amount billed 1,980 1,934 Unbilled recoverable costs 5,842 7,352 7,822 9,286 Accounts receivable, net $ 46,189 $ 68,521 (1) Additional long-term unbilled recoverable costs of $11.2 million and $12.8 million are included within “Other assets” as of April 30, 2018 and October 31, 2017, respectively. (2) Total U.S. government accounts receivable, including unbilled recoverable cost, outstanding as of April 30, 2018 and October 31, 2017 were $4.5 million and $3.2 million, respectively.

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Apr. 30, 2018
Inventory Disclosure [Abstract]
Components of Inventories	Inventories as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Raw materials $ 19,355 $ 20,065 Work-in-process (1) 35,900 54,431 Inventories $ 55,255 $ 74,496 (1) Work-in-process includes the standard components of inventory used to build the typical modules or module components that are intended to be used in future power plant orders or to service our service agreements. Included in work-in-process as of April 30, 2018 and October 31, 2017 was $29.3 million and $46.3 million, respectively, of completed standard components.

Other Current Assets (Tables)

Other Current Assets (Tables)	6 Months Ended
	Apr. 30, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Schedule of Other Current Assets	Other current assets as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Advance payments to vendors (1) $ 2,714 $ 1,035 Deferred finance costs (2) 129 129 Prepaid expenses and other (3) 5,095 5,407 Other current assets $ 7,938 $ 6,571 (1) Advance payments to vendors relate to payments for inventory purchases ahead of receipt. (2) Represents the current portion of direct deferred finance costs that relate primarily to securing the $40.0 million loan facility with NRG which is being amortized over the five-year life of the facility. (3) Primarily relates to other prepaid expenses including insurance, rent and lease payments.

Other Assets (Tables)

Other Assets (Tables)	6 Months Ended
	Apr. 30, 2018
Other Assets Noncurrent [Abstract]
Schedule of Other Assets	Other assets as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Long-term stack residual value (1) $ 1,096 $ 987 Deferred finance costs (2) 32 97 Long-term unbilled recoverable costs (3) 11,153 12,806 Other (4) 2,840 2,627 Other assets $ 15,121 $ 16,517 (1) Relates to estimated residual value for module exchanges performed under the Company’s service agreements where the useful life extends beyond the contractual term of the service agreement and the Company obtains title to the module from the customer upon expiration or termination of the service agreement. If the Company does not obtain rights to title from the customer, the full cost of the module is expensed at the time of the module exchange. (2) Represents the long-term portion of direct deferred finance costs relating to the Company’s loan facility with NRG which is being amortized over the five-year life of the facility. (3) Represents unbilled recoverable costs that relate to revenue recognized on customer contracts that will be billed in future periods in excess of twelve months from the balance sheet date. (4) The Company entered into an agreement with one of its customers on June 29, 2016 which includes a fee for the purchase of the plants at the end of the term of the agreement. The fee is payable in installments over the term of the agreement and the total paid as of April 30, 2018 and October 31, 2017 was $2.0 million and $1.6 million, respectively. Also included within “Other” are long-term security deposits.

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Apr. 30, 2018
Accrued Liabilities Current [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Accrued payroll and employee benefits $ 3,124 $ 5,315 Accrued contract loss — 37 Accrued product warranty cost (1) 343 348 Accrued material purchases (2) 548 2,396 Accrued service agreement costs (3) 1,726 3,319 Contractual milestone billings for inventory (4) 5,921 4,440 Accrued legal, taxes, professional and other 3,069 2,526 Accrued liabilities $ 14,731 $ 18,381 (1) Activity in the accrued product warranty costs for the six months ended April 30, 2018 included additions for estimates of future warranty obligations of $0.3 million on contracts in the warranty period and reductions related to actual warranty spend of $0.3 million as contracts progress through the warranty period or are beyond the warranty period. (2) The Company acts as a procurement agent for POSCO Energy under an Integrated Global Supply Chain Agreement whereby the Company procures materials on POSCO Energy’s behalf for its Korean production facility. This liability represents amounts received for the purchase of materials on behalf of POSCO Energy. Amounts due to vendors is recorded as “Accounts payable.” (3) The loss accruals on service contracts were $1.1 million as of October 31, 2017 which decreased to $1.0 million as of April 30, 2018. The accruals for performance guarantees decreased from $2.2 million as of October 31, 2017 to $0.7 million as of April 30, 2018 resulting from payments offset by additional accruals for the minimum power output falling below the contract requirements for certain service agreements. (4) Amounts represent contractual milestone billings for inventory that will be provided to POSCO Energy within the next twelve months under a transaction that will not result in revenue recognition.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Apr. 30, 2018
Equity [Abstract]
Schedule of Stockholders' Equity	Changes in stockholders’ equity were as follows for the six months ended April 30, 2018: Total Stockholders’ Equity Balance as of October 31, 2017 $ 101,256 Share-based compensation 1,378 Proceeds from common stock issuance and warrant exercises, net of fees 3,268 Common stock issued, non-employee compensation 282 Taxes paid upon vesting of restricted stock awards, net of stock issued under benefit plans (621 ) Preferred dividends – Series B (1,600 ) Conversion of Redeemable Series C preferred stock 15,598 Other comprehensive income - foreign currency translation adjustments 87 Net loss (17,357 ) Balance as of April 30, 2018 $ 102,291
Schedule of Stockholders' Equity Note, Warrants or Rights	The following table summarizes outstanding warrant activity during the six months ended April 30, 2018: Series A Warrants Series C Warrants Series D Warrants Balance as of October 31, 2017 7,680,000 11,580,900 2,584,174 Warrants exercised — (11,536 ) (2,584,174 ) Warrants expired — — — Balance as of April 30, 2018 7,680,000 11,569,364 —

Loss Per Share (Tables)

Loss Per Share (Tables)	6 Months Ended
	Apr. 30, 2018
Earnings Per Share [Abstract]
Calculation of Basic and Diluted Loss Per Share	The calculation of basic and diluted loss per share was as follows: Three Months Ended April 30, Six Months Ended April 30, 2018 2017 2018 2017 Numerator Net loss $ (13,174 ) $ (13,238 ) $ (17,357 ) $ (26,923 ) Series C preferred stock deemed dividends (4,199 ) — (7,662 ) — Series B preferred stock dividends (800 ) (800 ) (1,600 ) (1,600 ) Net loss attributable to common stockholders $ (18,173 ) $ (14,038 ) $ (26,619 ) $ (28,523 ) Denominator Weighted average basic common shares 79,563,265 42,568,818 75,731,565 40,049,948 Effect of dilutive securities (1) — — — — Weighted average diluted common shares 79,563,265 42,568,818 75,731,565 40,049,948 Basic loss per share $ (0.23 ) $ (0.33 ) $ (0.35 ) $ (0.71 ) Diluted loss per share (1) $ (0.23 ) $ (0.33 ) $ (0.35 ) $ (0.71 ) (1) Due to the net loss to common stockholders in each of the periods presented above, diluted loss per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive. As of April 30, 2018 and 2017, potentially dilutive securities excluded from the diluted loss per share calculation are as follows:
Schedule of Potentially Dilutive Securities Excluded from the Diluted Loss Per Share Calculation	As of April 30, 2018 and 2017, potentially dilutive securities excluded from the diluted loss per share calculation are as follows: April 30, April 30, 2018 2017 May 2017 Offering - Series C Warrants 11,569,364 — July 2016 Offering - Series A Warrants 7,680,000 7,680,000 July 2014 Offering - NRG Warrant — 166,666 Outstanding options to purchase common stock 327,890 214,383 Unvested Restricted Stock Awards 1,185,457 1,986,732 Series C Preferred Shares to satisfy conversion requirements (1) 7,906,783 — 5% Series B Cumulative Convertible Preferred Stock 454,043 454,043 Series 1 Preferred Shares to satisfy conversion requirements 15,166 15,166 Total potentially dilutive securities 29,138,703 10,516,990 (1) The number of shares of common stock issuable upon conversion of the Series C Preferred Stock was calculated using the stated value outstanding on April 30, 2018 of $14.5 million (original stated value of $33.5 million less the stated value of conversions to date through April 30, 2018 totaling $19.0 million) divided by the conversion price of $1.84. The actual number of shares issued could vary depending on the actual market price of the Company’s common shares on the date of such conversions.

Debt and Financing Obligation (

Debt and Financing Obligation (Tables)	6 Months Ended
	Apr. 30, 2018
Debt [Abstract]
Schedule of Debt	Debt as of April 30, 2018 and October 31, 2017 consisted of the following: April 30, October 31, 2018 2017 Connecticut Development Authority Note $ 2,256 $ 2,349 Connecticut Green Bank Note 6,051 6,052 Financing obligation for sale-leaseback transactions 46,110 46,937 State of Connecticut Loan 10,000 10,000 Hercules Loan and Security Agreement 26,754 21,468 New Britain Renewable Energy Term Loan 1,402 1,697 Equipment financing and capital lease obligations 489 632 Deferred finance costs (1,455 ) (1,344 ) Total debt $ 91,607 $ 87,791 Current portion of long-term debt and financing obligation (10,094 ) (28,281 ) Long-term debt $ 81,513 $ 59,510

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Apr. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Non-Cancelable Minimum Payments Applicable to Operating and Capital Leases	Non-cancelable minimum payments applicable to operating and capital leases as of April 30, 2018 were as follows: Operating Leases Capital Leases Due Year 1 $ 685 $ 300 Due Year 2 502 146 Due Year 3 367 36 Due Year 4 382 5 Due Year 5 376 2 Thereafter 3,190 — Total $ 5,502 $ 489

Nature of Business and Basis 35

Nature of Business and Basis of Presentation - Additional Information (Details)	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
POSCO Energy [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Common stock ownership percentage	3.00%		3.00%
Significant customer revenue percentage	4.00%	7.00%	3.00%	8.00%
NRG Energy, Inc. [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Common stock ownership percentage	2.00%		2.00%
Significant customer revenue percentage	52.00%	0.30%	18.10%	0.40%

Accounts Receivable, Net - Sche

Accounts Receivable, Net - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Oct. 31, 2017
Receivables [Abstract]
Contract receivable		$ 15,621	$ 41,073
Unbilled contracts receivable	[1]	22,746	18,162
Commercial customers accounts receivable		38,367	59,235
Advanced Technologies including U.S. government, Amount billed receivable		1,980	1,934
Advanced Technologies including U.S. government, Unbilled recoverable costs receivable		5,842	7,352
Advanced Technologies including U.S. government, Accounts receivable	[2]	7,822	9,286
Accounts receivable, net		$ 46,189	$ 68,521
[1]	Additional long-term unbilled recoverable costs of $11.2 million and $12.8 million are included within “Other assets” as of April 30, 2018 and October 31, 2017, respectively.
[2]	Total U.S. government accounts receivable, including unbilled recoverable cost, outstanding as of April 30, 2018 and October 31, 2017 were $4.5 million and $3.2 million, respectively.

Accounts Receivable, Net - Sc37

Accounts Receivable, Net - Schedule of Accounts Receivable (Details) (Parenthetical) - USD ($) $ in Millions	Apr. 30, 2018	Oct. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Long-term investments and receivables, net	$ 11.2	$ 12.8
Government [Member]
Accounts Notes And Loans Receivable [Line Items]
U.S. government accounts receivable, including unbilled recoverable cost	$ 4.5	$ 3.2

Accounts Receivable, Net - Addi

Accounts Receivable, Net - Additional Information (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 100	$ 100
POSCO Energy [Member]
Accounts Notes And Loans Receivable [Line Items]
Accounts Receivable, Related Parties, Current	12,200	6,200
NRG Energy, Inc. [Member]
Accounts Notes And Loans Receivable [Line Items]
Accounts Receivable, Related Parties, Current	$ 20	$ 100

Inventories - Components of Inv

Inventories - Components of Inventories (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Oct. 31, 2017
Inventory Disclosure [Abstract]
Raw materials		$ 19,355	$ 20,065
Work-in-process	[1]	35,900	54,431
Inventories		$ 55,255	$ 74,496
[1]	Work-in-process includes the standard components of inventory used to build the typical modules or module components that are intended to be used in future power plant orders or to service our service agreements. Included in work-in-process as of April 30, 2018 and October 31, 2017 was $29.3 million and $46.3 million, respectively, of completed standard components.

Inventories - Components of I40

Inventories - Components of Inventories (Parenthetical) (Details) - USD ($) $ in Millions	Apr. 30, 2018	Oct. 31, 2017
Inventory Disclosure [Abstract]
Completed Standard Component	$ 29.3	$ 46.3

Project Assets - Additional Inf

Project Assets - Additional Information (Details) $ in Thousands	Apr. 05, 2018USD ($)	Apr. 30, 2018USD ($)ProjectAsset	Oct. 31, 2017USD ($)ProjectAsset
Project Assets [Abstract]
Long-term project assets construction in progress		$ 48,500	$ 40,900
Long-term project assets		$ 79,595	$ 73,001
Number of project assets | ProjectAsset		5	5
Sale leaseback transaction, net book value		$ 31,100	$ 32,100
Project revenue	$ 10,800
Reduction in project assets relating to sale	$ 9,800
Impairment on project asset		$ 500

Other Current Assets - Schedule

Other Current Assets - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Oct. 31, 2017
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Advance payments to vendors	[1]	$ 2,714	$ 1,035
Deferred finance costs	[2]	129	129
Prepaid expenses and other	[3]	5,095	5,407
Other current assets		$ 7,938	$ 6,571
[1]	Advance payments to vendors relate to payments for inventory purchases ahead of receipt.
[2]	Represents the current portion of direct deferred finance costs that relate primarily to securing the $40.0 million loan facility with NRG which is being amortized over the five-year life of the facility.
[3]	Primarily relates to other prepaid expenses including insurance, rent and lease payments.

Other Current Assets - Schedu43

Other Current Assets - Schedule of Other Current Assets (Parenthetical) (Details) - NRG Energy, Inc. [Member]	6 Months Ended
	Apr. 30, 2018USD ($)
Other Current Assets [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 40,000,000
Line of credit facility, expiration period	5 years

Other Assets - Schedule of Othe

Other Assets - Schedule of Other Assets (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Oct. 31, 2017
Other Assets Noncurrent [Abstract]
Long-term stack residual value	[1]	$ 1,096	$ 987
Deferred finance costs	[2]	32	97
Long-term unbilled recoverable costs	[3]	11,153	12,806
Other	[4]	2,840	2,627
Other assets		$ 15,121	$ 16,517
[1]	Relates to estimated residual value for module exchanges performed under the Company’s service agreements where the useful life extends beyond the contractual term of the service agreement and the Company obtains title to the module from the customer upon expiration or termination of the service agreement. If the Company does not obtain rights to title from the customer, the full cost of the module is expensed at the time of the module exchange.
[2]	Represents the long-term portion of direct deferred finance costs relating to the Company’s loan facility with NRG which is being amortized over the five-year life of the facility.
[3]	Represents unbilled recoverable costs that relate to revenue recognized on customer contracts that will be billed in future periods in excess of twelve months from the balance sheet date.
[4]	The Company entered into an agreement with one of its customers on June 29, 2016 which includes a fee for the purchase of the plants at the end of the term of the agreement. The fee is payable in installments over the term of the agreement and the total paid as of April 30, 2018 and October 31, 2017 was $2.0 million and $1.6 million, respectively. Also included within “Other” are long-term security deposits.

Other Assets - Schedule of Ot45

Other Assets - Schedule of Other Assets (Parenthetical) (Details) $ in Millions	6 Months Ended
	Apr. 30, 2018USD ($)	Oct. 31, 2017USD ($)	Jun. 29, 2016Customer
Other Assets Noncurrent [Abstract]
Deferred finance costs amortization period	5 years
Number of customers under agreement | Customer			1
Contractual Obligation | $	$ 2	$ 1.6

Accounts Payable - Additional I

Accounts Payable - Additional Information (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Oct. 31, 2017
Schedule Of Accounts Payable [Line Items]
Accounts payable	$ 42,813	$ 42,616
POSCO Energy [Member]
Schedule Of Accounts Payable [Line Items]
Accounts Payable, Related Parties, Current	$ 32,700	$ 32,700

Schedule of Accrued Liabilities

Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Oct. 31, 2017
Accrued Liabilities Current [Abstract]
Accrued payroll and employee benefits		$ 3,124	$ 5,315
Accrued contract loss		0	37
Accrued product warranty cost	[1]	343	348
Accrued material purchases	[2]	548	2,396
Accrued service agreement costs	[3]	1,726	3,319
Contractual milestone billings for inventory	[4]	5,921	4,440
Accrued legal, taxes, professional and other		3,069	2,526
Accrued liabilities		$ 14,731	$ 18,381
[1]	Activity in the accrued product warranty costs for the six months ended April 30, 2018 included additions for estimates of future warranty obligations of $0.3 million on contracts in the warranty period and reductions related to actual warranty spend of $0.3 million as contracts progress through the warranty period or are beyond the warranty period.
[2]	The Company acts as a procurement agent for POSCO Energy under an Integrated Global Supply Chain Agreement whereby the Company procures materials on POSCO Energy’s behalf for its Korean production facility. This liability represents amounts received for the purchase of materials on behalf of POSCO Energy. Amounts due to vendors is recorded as “Accounts payable.”
[3]	The loss accruals on service contracts were $1.1 million as of October 31, 2017 which decreased to $1.0 million as of April 30, 2018. The accruals for performance guarantees decreased from $2.2 million as of October 31, 2017 to $0.7 million as of April 30, 2018 resulting from payments offset by additional accruals for the minimum power output falling below the contract requirements for certain service agreements.
[4]	Amounts represent contractual milestone billings for inventory that will be provided to POSCO Energy within the next twelve months under a transaction that will not result in revenue recognition.

Schedule of Accrued Liabiliti48

Schedule of Accrued Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	6 Months Ended
	Apr. 30, 2018	Oct. 31, 2017
Accrued Liabilities Current [Abstract]
Product warranty accrual, warranties issued	$ 0.3
Product warranty accrual, payment and adjustments	0.3
Gain reserve on service agreements	1	$ 1.1
Reserve for performance guarantees	$ 0.7	$ 2.2

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Stockholders Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of October 31, 2017			$ 101,256
Foreign currency translation adjustments	$ 54	$ 32	87	$ (38)
Net loss	(13,174)	$ (13,238)	(17,357)	$ (26,923)
Balance as of April 30, 2018	102,291		102,291
Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of October 31, 2017			101,256
Share-based compensation			1,378
Proceeds from common stock issuance and warrant exercises, net of fees			3,268
Common stock issued, non-employee compensation			282
Taxes paid upon vesting of restricted stock awards, net of stock issued under benefit plans			(621)
Preferred dividends – Series B			(1,600)
Conversion of Redeemable Series C preferred stock			15,598
Foreign currency translation adjustments			87
Net loss			(17,357)
Balance as of April 30, 2018	$ 102,291		$ 102,291

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 14, 2017	May 03, 2017	Apr. 30, 2018	Oct. 31, 2017
Stockholders' Equity Note
Common stock, shares authorized			225,000,000	125,000,000
Excess percentage of common shares outstanding	19.90%
Series C Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding			11,569,364	11,580,900
Series D Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding				2,584,174
Series A Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 5.83
Class of Warrant or Right, Outstanding			7,680,000
Common Stock | Series C Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			11,536
Net proceeds from common stock and warrants			$ 20
Common Stock | Series D Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			2,584,174
Net proceeds from common stock and warrants			$ 3,300
Convertible Preferred Offering [Member] | Series C Preferred Stock [Member]
Stockholders' Equity Note
Preferred stock offering date	2017-09
Underwritten Public Offering [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues		12,000,000
Underwritten Public Offering [Member] | Series C Warrants [Member]
Stockholders' Equity Note
Class of warrants or rights issued		12,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.60
Class of warrant or right term		5 years
Underwritten Public Offering [Member] | Series D Warrants [Member]
Stockholders' Equity Note
Class of warrants or rights issued		12,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.28
Class of warrant or right term		1 year

Stockholders' Equity - Schedu51

Stockholders' Equity - Schedule of Warrant Activity (Details)	6 Months Ended
	Apr. 30, 2018shares
Series A Warrant [Member]
Balance as of October 31, 2017	7,680,000
Balance as of April 30, 2018	7,680,000
Series C Warrants [Member]
Balance as of October 31, 2017	11,580,900
Warrants exercised	(11,536)
Balance as of April 30, 2018	11,569,364
Series D Warrants [Member]
Balance as of October 31, 2017	2,584,174
Warrants exercised	(2,584,174)

Redeemable Preferred Stock - Ad

Redeemable Preferred Stock - Additional Information (Details) $ / shares in Units, $ in Thousands, $ in Millions	Nov. 01, 2017USD ($)Installment	Apr. 30, 2018USD ($)$ / sharesshares	Apr. 30, 2017USD ($)	Apr. 30, 2018USD ($)TradingDay$ / sharesshares	Apr. 30, 2018CAD ($)TradingDayshares	Apr. 30, 2017USD ($)	Oct. 31, 2017CAD ($)shares	Apr. 30, 2018CAD ($)shares	Oct. 31, 2017USD ($)$ / sharesshares	Oct. 31, 2017CAD ($)shares
Class Of Stock [Line Items]
Preferred stock, shares authorized | shares		250,000		250,000				250,000
Preferred stock, par value | $ / shares		$ 0.01		$ 0.01
Convertible preferred stock, reduction in carrying amount | $				$ 15,600
Series B Cumulative Convertible Perpetual Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock, shares authorized | shares		105,875		105,875				105,875	105,875	105,875
Preferred stock, dividend rate, percentage				5.00%	5.00%		5.00%
Preferred stock, shares issued | shares		64,020		64,020				64,020	64,020	64,020
Preferred stock, shares outstanding | shares		64,020		64,020				64,020	64,020	64,020
Temporary equity, carrying amount, attributable to parent | $		$ 59,857		$ 59,857					$ 59,857
Preferred stock, liquidation preference per share | $ / shares		$ 1,000		$ 1,000					$ 1,000
Dividends, preferred stock, cash | $				$ 1,600		$ 1,600
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage				15.00%	15.00%
Temporary equity, carrying amount, attributable to parent | $		$ 12,102		$ 12,102					$ 27,700
Convertible preferred stock, converted into common stock | shares				18,752	18,752
Conversion of stock conversion price | $ / shares		$ 1.84		$ 1.84
Preferred stock deemed dividends | $		$ 4,199	$ 0	$ 7,662		$ 0
Preferred stock redemption terms				Installment Payments. On November 1, 2017 and on the sixteenth day and first day of each calendar month thereafter until March 1, 2019, subject to extension in certain circumstances (the “Maturity Date”), inclusive, the Company will redeem the stated value of Series C Preferred Shares in thirty-three equal installments of $1.0 million (each bimonthly amount, an “Installment Amount” and the date of each such payment, an “Installment Date”). The holders will have the ability to defer installment payments, but not beyond the Maturity Date. In addition, during each period commencing on the 11th trading day prior to an Installment Date and prior to the immediately subsequent Installment Date, the holders may elect to accelerate the conversion of Series C Preferred Shares at the then applicable installment conversion price, provided that the holders may not elect to effect any such acceleration during such installment period if either (a) in the aggregate, all the accelerations in such installment period exceed the sum of three other Installment Amounts, or (b) the number of Series C Preferred Shares subject to prior accelerations exceeds in the aggregate twelve Installment Amounts.	Installment Payments. On November 1, 2017 and on the sixteenth day and first day of each calendar month thereafter until March 1, 2019, subject to extension in certain circumstances (the “Maturity Date”), inclusive, the Company will redeem the stated value of Series C Preferred Shares in thirty-three equal installments of $1.0 million (each bimonthly amount, an “Installment Amount” and the date of each such payment, an “Installment Date”). The holders will have the ability to defer installment payments, but not beyond the Maturity Date. In addition, during each period commencing on the 11th trading day prior to an Installment Date and prior to the immediately subsequent Installment Date, the holders may elect to accelerate the conversion of Series C Preferred Shares at the then applicable installment conversion price, provided that the holders may not elect to effect any such acceleration during such installment period if either (a) in the aggregate, all the accelerations in such installment period exceed the sum of three other Installment Amounts, or (b) the number of Series C Preferred Shares subject to prior accelerations exceeds in the aggregate twelve Installment Amounts.
Preferred stock redemption maturity date				Mar. 1, 2019	Mar. 1, 2019
Number of preferred stock redemption equal installments | Installment	33
Redemption of preferred shares in installments, each installment amount | $	$ 1,000
Common stock consecutive trading day | TradingDay				10	10
Repayment percentage of installment amount				108.00%	108.00%
Preferred shares, triggering event redemption terms				Redemption. In the event of a triggering event, as defined in the Certificate of Designations, the holders of the Series C Preferred Shares can force redemption at a price equal to the greater of (a) the conversion amount to be redeemed multiplied by 125% and (b) the product of (i) the conversion rate with respect to the conversion amount in effect at such time as such holder delivers a triggering event redemption notice multiplied by (ii) the greatest closing sale price of the common stock on any trading day during the period commencing on the date immediately preceding such triggering event and ending on the date the Company makes the entire payment required.	Redemption. In the event of a triggering event, as defined in the Certificate of Designations, the holders of the Series C Preferred Shares can force redemption at a price equal to the greater of (a) the conversion amount to be redeemed multiplied by 125% and (b) the product of (i) the conversion rate with respect to the conversion amount in effect at such time as such holder delivers a triggering event redemption notice multiplied by (ii) the greatest closing sale price of the common stock on any trading day during the period commencing on the date immediately preceding such triggering event and ending on the date the Company makes the entire payment required.
Redemption pice percentage				125.00%	125.00%
Preferred shares voting rights				no voting rights	no voting rights
Series C Preferred Stock [Member] | Volume Weighted Average Price [Member]
Class Of Stock [Line Items]
Percentage of common stock on trading day immediately prior to applicable installment date				87.50%	87.50%
Series C Preferred Stock [Member] | Arithmetic Average Of Two Lowest Volume Weighted Average Price [Member]
Class Of Stock [Line Items]
Percentage of common stock on trading day immediately prior to applicable installment date				87.50%	87.50%
Series C Preferred Stock [Member] | Convertible Preferred Offering [Member]
Class Of Stock [Line Items]
Aggregate number of shares issued | shares							33,500
Sale of stock price per share | $ / shares									$ 0.01
Preferred stock, stated value per share | $ / shares									$ 1,000
Preferred stock, shares issued | shares		14,548		14,548				14,548	33,300	33,300
Preferred stock, shares outstanding | shares		14,548		14,548				14,548	33,300	33,300
Temporary equity, carrying amount, attributable to parent | $		$ 12,100		$ 12,100					$ 27,700
Conversion of stock conversion price | $ / shares		$ 1.84		$ 1.84
Convertible preferred stock, terms of conversion				Conversion Rights. The Series C Preferred Shares are convertible into shares of common stock subject to the beneficial ownership limitations provided in the Certificate of Designations for Series C Preferred Stock (the “Certificate of Designations”), at a conversion price equal to $1.84 per share of common stock (“Conversion Price”), subject to adjustment as provided in the Certificate of Designations, at any time at the option of the holder. In the event of a triggering event, as defined in the Certificate of Designations, the Series C Preferred Shares are convertible into shares of common stock at a conversion price of the lower of $1.84 per share and 85% of the lowest volume weighted average price (“VWAP”) of the common stock of the five trading days immediately prior to delivery of the applicable conversion notice. The holders will be prohibited from converting Series C Preferred Shares into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would own more than 8.99% of the total number of shares of common stock then issued and outstanding. Each holder has the right to increase its maximum percentage up to 9.99% upon 60 days’ notice to the Company.	Conversion Rights. The Series C Preferred Shares are convertible into shares of common stock subject to the beneficial ownership limitations provided in the Certificate of Designations for Series C Preferred Stock (the “Certificate of Designations”), at a conversion price equal to $1.84 per share of common stock (“Conversion Price”), subject to adjustment as provided in the Certificate of Designations, at any time at the option of the holder. In the event of a triggering event, as defined in the Certificate of Designations, the Series C Preferred Shares are convertible into shares of common stock at a conversion price of the lower of $1.84 per share and 85% of the lowest volume weighted average price (“VWAP”) of the common stock of the five trading days immediately prior to delivery of the applicable conversion notice. The holders will be prohibited from converting Series C Preferred Shares into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would own more than 8.99% of the total number of shares of common stock then issued and outstanding. Each holder has the right to increase its maximum percentage up to 9.99% upon 60 days’ notice to the Company.
Percentage of lowest volume weighted average price of common stock considered as conversion price				85.00%	85.00%
Conversion terms, increase beneficial ownership limitation percentage upon notice periods				60 days	60 days
Series C Preferred Stock [Member] | Convertible Preferred Offering [Member] | Minimum [Member]
Class Of Stock [Line Items]
Conversion terms, beneficial ownership limitation, percentage				8.99%	8.99%
Series C Preferred Stock [Member] | Convertible Preferred Offering [Member] | Maximum [Member]
Class Of Stock [Line Items]
Conversion terms, beneficial ownership increase, percentage				9.99%	9.99%
Class A Cumulative Redeemable Exchangeable Preferred Shares [Member]
Class Of Stock [Line Items]
Preferred stock, shares outstanding | shares		1,000,000		1,000,000				1,000,000
Return of capital and dividend payments | $					$ 0.5		$ 0.5
Interest expense, other | $					$ 1.4		$ 1.3
Carrying value of preferred shares, total		$ 15,700		$ 15,700				$ 20.1	$ 15,100	$ 19.4

Loss Per Share - Calculation of

Loss Per Share - Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Numerator
Net loss		$ (13,174)	$ (13,238)	$ (17,357)	$ (26,923)
Net loss attributable to common stockholders		$ (18,173)	$ (14,038)	$ (26,619)	$ (28,523)
Denominator
Weighted average basic common shares		79,563,265	42,568,818	75,731,565	40,049,948
Effect of dilutive securities	[1]	0	0	0	0
Weighted average diluted common shares		79,563,265	42,568,818	75,731,565	40,049,948
Basic loss per share		$ (0.23)	$ (0.33)	$ (0.35)	$ (0.71)
Diluted loss per share	[1]	$ (0.23)	$ (0.33)	$ (0.35)	$ (0.71)
Series C Preferred Stock [Member]
Numerator
Series C preferred stock deemed dividends		$ (4,199)	$ 0	$ (7,662)	$ 0
Series B Preferred Stock [Member]
Numerator
Series B preferred stock dividends		$ (800)	$ (800)	$ (1,600)	$ (1,600)
[1]	Due to the net loss to common stockholders in each of the periods presented above, diluted loss per share was computed without consideration to potentially dilutive instruments as their inclusion would have been antidilutive. As of April 30, 2018 and 2017, potentially dilutive securities excluded from the diluted loss per share calculation are as follows:

Loss Per Share - Schedule of Po

Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from the Diluted Loss Per Share Calculation (Details) - shares		6 Months Ended
		Apr. 30, 2018	Apr. 30, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, number		327,890	214,383
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number		4,300,000
Antidilutive securities excluded from computation of earnings per share, amount		29,138,703	10,516,990
Series C Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Class of warrant or right, number of securities called by warrants or rights		11,569,364
Series A Warrant [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Class of warrant or right, number of securities called by warrants or rights		7,680,000	7,680,000
NRG Warrant [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Class of warrant or right, number of securities called by warrants or rights			166,666
Unvested Restricted Stock Awards [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number		1,185,457	1,986,732
Series C Preferred Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Convertible preferred stock, shares issued upon conversion	[1]	7,906,783	0
Series B Cumulative Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Convertible preferred stock, shares issued upon conversion		454,043	454,043
Series 1 Preferred Shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Convertible preferred stock, shares issued upon conversion		15,166	15,166
[1]	The number of shares of common stock issuable upon conversion of the Series C Preferred Stock was calculated using the stated value outstanding on April 30, 2018 of $14.5 million (original stated value of $33.5 million less the stated value of conversions to date through April 30, 2018 totaling $19.0 million) divided by the conversion price of $1.84. The actual number of shares issued could vary depending on the actual market price of the Company’s common shares on the date of such conversions.

Loss Per Share - Schedule of 55

Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from the Diluted Loss Per Share Calculation (Parenthetical) (Details) - Series C Preferred Stock [Member] $ / shares in Units, $ in Millions	6 Months Ended
	Apr. 30, 2018USD ($)$ / shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Preferred stock, stated value	$ 14.5
Preferred stock, original total stated value	33.5
Preferred stock, conversion amount	$ 19
Conversion of stock conversion price | $ / shares	$ 1.84

Restricted Cash - Additional In

Restricted Cash - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Apr. 30, 2018	Oct. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents	$ 38,200	$ 38,200
Restricted cash and cash equivalents - long-term	32,965	33,526
Reserves for obligations	$ 17,200	17,000
Letter of credit date of expiration	Apr. 30, 2019
Letters of credit outstanding, amount	$ 2,300	2,900
Dominion Bridgeport FuelCell Park [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents - long-term	$ 15,000	$ 15,000
Restricted cash and cash equivalents - long-term service agreement	15 years

Debt and Financing Obligation -

Debt and Financing Obligation - Schedule of Debt (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Mar. 28, 2018	Oct. 31, 2017	Nov. 30, 2015
Debt Instrument [Line Items]
Equipment financing and capital lease obligations	$ 489		$ 632
Deferred finance costs	(1,455)		(1,344)
Total debt	91,607		87,791
Current portion of long-term debt and financing obligation	(10,094)		(28,281)
Long-term debt	81,513		59,510
Connecticut Development Authority Note [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	2,256		2,349
Connecticut Green Bank Note [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	6,051		6,052
Financing Obligation for Sale-Lease Back Transactions [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	46,110		46,937
State of Connecticut Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	10,000		10,000	$ 10,000
Hercules Capital, Inc. [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	26,754	$ 11,900	21,468
New Britain Renewable Energy Term Loan [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 1,402		$ 1,697

Debt and Financing Obligation58

Debt and Financing Obligation - Additional Information (Details) - USD ($)	Mar. 28, 2018	Jan. 31, 2018	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2017	Oct. 31, 2016	Oct. 01, 2020	Oct. 31, 2018	Nov. 30, 2016	Nov. 30, 2015	Mar. 05, 2013
Debt Instrument [Line Items]
Proceeds from Issuance of Debt			$ 13,091,000	$ 17,891,000
Lease payment term			36 months
Connecticut Development Authority Note [Member]
Debt Instrument [Line Items]
Collateralized Agreements			$ 4,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.00%
Long-term Line of Credit			$ 2,256,000		$ 2,349,000
Connecticut Green Bank Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage											5.00%
Line of Credit Facility, Maximum Borrowing Capacity											$ 5,900,000
Long-term Line of Credit			6,051,000		6,052,000
PNC Energy Capital, LLC [Member]
Debt Instrument [Line Items]
Long-term Line of Credit			46,100,000		46,900,000
CT Department of Economic & Community Development [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 10,000,000
State of Connecticut [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.00%
Debt Instrument, Face Amount			$ 10,000,000		10,000,000					$ 10,000,000
Term of loan			15 years
Hercules Capital, Inc. [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 25,000,000
Long-term Line of Credit	$ 11,900,000		$ 26,754,000		$ 21,468,000
Term of loan			30 months
Proceeds from Issuance of Debt						$ 20,000,000
Debt Instrument, Interest Rate, Stated Percentage Rate Range	10.15%
Loan Advance	$ 13,100,000
Term Loan Maturity Date			Oct. 1, 2020
Hercules Capital, Inc. [Member] | Series C Preferred Stock [Member]
Debt Instrument [Line Items]
Debt instrument, amendment description			As collateral for obligations under the Hercules Agreement, as amended, the Company granted Hercules a security interest in FuelCell Energy, Inc.’s existing and thereafter-acquired assets except for intellectual property and certain other excluded assets. The collateral does not include assets held by FuelCell Energy Finance, LLC (“FuelCell Finance”) or any project subsidiary thereof. The Company may continue to collateralize and finance its project subsidiaries through other lenders and partners. Under the Hercules Agreement, as amended, there is a minimum cash covenant which requires the Company to maintain an unrestricted cash balance in accounts subject to an account control agreement in favor of Hercules of at least the greater of (x) (a) 75% of the outstanding loan balance plus (b) the amount of accounts payable (as defined under GAAP) not paid within 90 days of the invoice date and (y) $10.0 million. The Hercules Agreement, as amended, contains customary representations and warranties, affirmative and negative covenants, and events of default that entitle Hercules to cause our indebtedness under the agreement to become immediately due and payable.
Cash covenant minimum required percentage of unrestricted cash balance on outstanding loan balance and accounts payable			75.00%
Minimum required unrestricted cash balance under control agreement			$ 10,000,000
Hercules Capital, Inc. [Member] | Scenario Forecast [Member]
Debt Instrument [Line Items]
Other Deductions and Charges							$ 900,000	$ 1,700,000
Hercules Capital, Inc. [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range					9.75%
Hercules Capital, Inc. [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range		10.00%
New Britain Renewable Energy Term Loan [Member]
Debt Instrument [Line Items]
Long-term Line of Credit			$ 1,402,000		$ 1,697,000
Debt Instrument, Interest Rate, Stated Percentage Rate Range			5.00%
Notes Payable to Bank, Current			$ 1,400,000						$ 2,300,000
NRG Energy, Inc. [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			40,000,000
Long-term Line of Credit			0		0
Proceeds from Issuance of Debt			$ 0		$ 0
NRG Energy, Inc. [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range			8.00%
NRG Energy, Inc. [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range			8.50%

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
	Apr. 30, 2018	Apr. 05, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units, granted, shares	2,200,000
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number	4,300,000
Stock Issued During Period, Shares, Issued for Services	158,708
Noninterest Expense Directors Fees	$ 0.3
Maximum [Member] | Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		500,000
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units, general vesting period	3 years
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units, general vesting period	4 years
2018 Omnibus Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance		4,000,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended	6 Months Ended		10 Months Ended
	Dec. 31, 2017	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2018
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit)		$ (36)	$ (3,035)	$ 45
U.S. federal corporate tax rate	34.00%
Reduction of valuation allowance attributable to deferred tax assets			2,000
IPR&D
Operating Loss Carryforwards [Line Items]
Reduction in deferred tax liability			$ 1,000
Scenario Plan [Member]
Operating Loss Carryforwards [Line Items]
U.S. federal corporate tax rate					21.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Apr. 30, 2018	Oct. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Capitalized lease obligations	$ 489	$ 632
Lease Payment Terms	36 months
Reserve for performance guarantees	$ 700	2,200
Loss reserve on service agreements	1,000	$ 1,100
Recorded Unconditional Purchase Obligation	$ 48,100

Commitments and Contingencies62

Commitments and Contingencies - Schedule of Non-Cancelable Minimum Payments Applicable to Operating and Capital Leases (Details) $ in Thousands	Apr. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating Leases, due in one year	$ 685
Operating Leases, due in two years	502
Operating Leases, due in three years	367
Operating Leases, due in four years	382
Operating Leases, due in five years	376
Operating Leases, due thereafter	3,190
Operating Leases, future minimum payments due	5,502
Capital Leases, future minimum payments due, next twelve months	300
Capital Leases, future minimum payments due in two years	146
Capital Leases, future minimum payments due in three years	36
Capital Leases, future minimum payments due in four years	5
Capital Leases, future minimum payments due in five years	2
Capital Leases, future minimum payments due thereafter	0
Capital Leases, future minimum payments due	$ 489