Fuel Tech (FTEK) 10-Q 11 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Document and Entity Information [Abstract]
Entity Registrant Name	FUEL TECH, INC.
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		24,701,159
Amendment Flag	false
Entity Central Index Key	0000846913
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q2

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 8,254,000	$ 10,914,000
Restricted cash	2,639,000	2,080,000
Accounts receivable, net	5,658,000	6,473,000
Inventories, net	342,000	264,000
Prepaid expenses and other current assets	1,410,000	1,879,000
Income taxes receivable	69,000	0
Total current assets	18,372,000	21,610,000
Property and equipment, net of accumulated depreciation of $26,503 and $26,174, respectively	5,437,000	5,662,000
Goodwill	2,116,000	2,116,000
Other intangible assets, net of accumulated amortization of $6,756 and $6,671, respectively	838,000	906,000
Restricted cash	364,000	507,000
Right-of-use operating lease assets	1,035,000	980,000
Other assets	395,000	443,000
Total assets	28,557,000	32,224,000
Current liabilities:
Accounts payable	1,585,000	2,117,000
Current portion of long-term borrowings	684,000	0
Accrued liabilities:
Operating lease liabilities - current	279,000	300,000
Employee compensation	679,000	519,000
Income taxes payable	36,000	0
Other accrued liabilities	2,104,000	1,976,000
Total current liabilities	5,367,000	4,912,000
Operating lease liabilities - non-current	738,000	680,000
Long-term borrowings, net of current portion	872,000	0
Deferred income taxes, net	172,000	171,000
Other liabilities	278,000	286,000
Total liabilities	7,427,000	6,049,000
COMMITMENTS AND CONTINGENCIES (Note 13)
Stockholders’ equity:
Common stock, $.01 par value, 40,000,000 shares authorized, 25,476,420 and 25,053,480 shares issued, and 24,701,159 and 24,592,578 shares outstanding, respectively	255,000	254,000
Additional paid-in capital	139,710,000	139,560,000
Accumulated deficit	(115,436,000)	(110,325,000)
Accumulated other comprehensive loss	(1,857,000)	(1,778,000)
Nil coupon perpetual loan notes	76,000	76,000
Treasury stock, at cost	(1,618,000)	(1,612,000)
Total stockholders’ equity	21,130,000	26,175,000
Total liabilities and stockholders’ equity	$ 28,557,000	$ 32,224,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
Costs and expenses:
Cost of sales	3,799	5,050	6,050	11,191
Selling, general and administrative	2,755	4,455	6,641	8,913
Restructuring charge	0	30	0	625
Research and development	271	205	595	471
Intangible assets abandonment	0	51	0	51
Costs and expenses:	6,825	9,791	13,286	21,251
Operating loss from continuing operations	(2,424)	(843)	(5,107)	(2,148)
Interest expense	(3)	(3)	(6)	(4)
Interest income	2	9	13	11
Other income (expense), net	(88)	(97)	138	(72)
Loss from continuing operations before income taxes	(2,513)	(934)	(4,962)	(2,213)
Income tax expense	(31)	(2)	(149)	(2)
Net loss (income) from continuing operations	(2,544)	(936)	(5,111)	(2,215)
Loss from discontinued operations	0	(9)	0	(19)
Net loss	$ (2,544)	$ (945)	$ (5,111)	$ (2,234)
Basic
Continuing operations (in dollars per share)	$ (0.10)	$ (0.04)	$ (0.21)	$ (0.09)
Discontinued operations (in dollars per share)	0	0	0	0
Basic net loss per common share (in dollars per share)	(0.10)	(0.04)	(0.21)	(0.09)
Diluted
Continuing operations (in dollars per share)	(0.10)	(0.04)	(0.21)	(0.09)
Discontinued operations (in dollars per share)	0	0	0	0
Diluted net loss per common share (in dollars per share)	$ (0.10)	$ (0.04)	$ (0.21)	$ (0.09)
Weighted-average number of common shares outstanding:
Basic (in shares)	24,668,000	24,187,000	24,633,000	24,182,000
Diluted (in shares)	24,668,000	24,187,000	24,633,000	24,182,000

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,795	$ 1,816
Accumulated depreciation	26,503	26,174
Accumulated amortization	$ 6,756	$ 6,671
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	25,476,420	25,053,480
Common stock outstanding (in shares)	24,701,159	24,592,578

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (2,544)	$ (945)	$ (5,111)	$ (2,234)
Other comprehensive income loss:
Foreign currency translation adjustments	152	(43)	(79)	61
Comprehensive loss	$ (2,392)	$ (988)	$ (5,190)	$ (2,173)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total accumulated other comprehensive loss	Nil Coupon Perpetual Loan Notes	Treasury Stock	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, AdjustmentAccumulated Deficit
Balance (in shares) at Dec. 31, 2018		24,170
Balance at beginning of period at Dec. 31, 2018	$ 34,052	$ 248	$ 138,992	$ (102,495)	$ (1,285)	$ 76	$ (1,484)	$ 22	$ 22
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(1,289)			(1,289)
Foreign currency translation adjustments	104				104
Stock compensation expense	96		96
Common shares issued upon vesting of restricted stock units (in shares)		18
Treasury shares withheld (in shares)		(2)
Treasury shares withheld	(2)						(2)
Balance (in shares) at Mar. 31, 2019		24,186
Balance at end of period at Mar. 31, 2019	32,983	$ 248	139,088	(103,762)	(1,181)	76	(1,486)
Balance (in shares) at Dec. 31, 2018		24,170
Balance at beginning of period at Dec. 31, 2018	34,052	$ 248	138,992	(102,495)	(1,285)	76	(1,484)	$ 22	$ 22
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(2,234)
Foreign currency translation adjustments	61
Balance (in shares) at Jun. 30, 2019		24,186
Balance at end of period at Jun. 30, 2019	32,118	$ 248	139,211	(104,707)	(1,224)	76	(1,486)
Balance (in shares) at Mar. 31, 2019		24,186
Balance at beginning of period at Mar. 31, 2019	32,983	$ 248	139,088	(103,762)	(1,181)	76	(1,486)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(945)			(945)
Foreign currency translation adjustments	(43)				(43)
Stock compensation expense	123		123
Balance (in shares) at Jun. 30, 2019		24,186
Balance at end of period at Jun. 30, 2019	32,118	$ 248	139,211	(104,707)	(1,224)	76	(1,486)
Balance (in shares) at Dec. 31, 2019		24,592
Balance at beginning of period at Dec. 31, 2019	26,175	$ 254	139,560	(110,325)	(1,778)	76	(1,612)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(2,567)			(2,567)
Foreign currency translation adjustments	(231)				(231)
Stock compensation expense	81		81
Common shares issued upon vesting of restricted stock units (in shares)		55
Treasury shares withheld (in shares)		(11)
Treasury shares withheld	(5)						(5)
Balance (in shares) at Mar. 31, 2020		24,636
Balance at end of period at Mar. 31, 2020	23,453	$ 254	139,641	(112,892)	(2,009)	76	(1,617)
Balance (in shares) at Dec. 31, 2019		24,592
Balance at beginning of period at Dec. 31, 2019	26,175	$ 254	139,560	(110,325)	(1,778)	76	(1,612)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,111)
Foreign currency translation adjustments	(79)
Balance (in shares) at Jun. 30, 2020		24,701
Balance at end of period at Jun. 30, 2020	21,130	$ 255	139,710	(115,436)	(1,857)	76	(1,618)
Balance (in shares) at Mar. 31, 2020		24,636
Balance at beginning of period at Mar. 31, 2020	23,453	$ 254	139,641	(112,892)	(2,009)	76	(1,617)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(2,544)			(2,544)
Foreign currency translation adjustments	152				152
Stock compensation expense	69		69
Common shares issued upon vesting of restricted stock units (in shares)		66
Common shares issued upon vesting of restricted stock units		$ 1					(1)
Treasury shares withheld (in shares)		(1)
Balance (in shares) at Jun. 30, 2020		24,701
Balance at end of period at Jun. 30, 2020	$ 21,130	$ 255	$ 139,710	$ (115,436)	$ (1,857)	$ 76	$ (1,618)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating Activities
Net loss	$ (5,111)	$ (2,234)
Loss from discontinued operations	0	19
Net loss (income) from continuing operations	(5,111)	(2,215)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	329	478
Amortization	85	68
Loss (gain) on disposal of equipment	0	(2)
Provision for doubtful accounts, net of recoveries	(1,082)	0
Intangible assets abandonment	0	51
Stock-based compensation, net of forfeitures	150	219
Changes in operating assets and liabilities:
Accounts receivable	1,863	3,870
Inventories	(78)	640
Prepaid expenses, other current assets and other non-current assets	424	1,163
Accounts payable	(531)	(5,595)
Accrued liabilities and other non-current liabilities	537	(1,485)
Net cash used in operating activities - continuing operations	(3,414)	(2,804)
Net cash used in operating activities - discontinued operations	0	(19)
Net cash used in operating activities	(3,414)	(2,823)
Investing Activities
Purchases of equipment and patents	(122)	(359)
Net cash used in investing activities - continuing operations	(122)	(359)
Financing Activities
Proceeds from borrowings	1,556	0
Taxes paid on behalf of equity award participants	(6)	(2)
Net cash used in financing activities	1,550	(2)
Effect of exchange rate fluctuations on cash	(258)	44
Net decrease in cash, cash equivalents and restricted cash	(2,244)	(3,140)
Cash, cash equivalents, and restricted cash at beginning of period (Note 2)	13,501	18,059
Cash, cash equivalents and restricted cash at end of period (Note 2)	$ 11,257	$ 14,919

General

General	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General Organization Fuel Tech, Inc. and subsidiaries ("Fuel Tech", the "Company", "we", "us" or "our") provides advanced engineered solutions for the optimization of combustion systems in utility and industrial applications. Our primary focus is on the worldwide marketing and sale of NO x reduction technologies as well as our FUEL CHEM program. The Company’s NO x reduction technologies reduce nitrogen oxide emissions from boilers, furnaces and other stationary combustion sources. Our FUEL CHEM program is based on proprietary TIFI ® Targeted In-Furnace™ Injection technology, in combination with advanced Computational Fluid Dynamics (CFD) and Chemical Kinetics Modeling (CKM) boiler modeling, in the unique application of specialty chemicals to improve the efficiency, reliability and environmental status of combustion units by controlling slagging, fouling, corrosion, opacity and other sulfur trioxide-related issues in the boiler. Our business is materially dependent on the continued existence and enforcement of air quality regulations, particularly in the United States. We have expended significant resources in the research and development of new technologies in building our proprietary portfolio of air pollution control, fuel and boiler treatment chemicals, computer modeling and advanced visualization technologies. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, the financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the statements for the periods presented. All significant intercompany transactions and balances have been eliminated. The results of operations for the three and six months ended June 30, 2020 are not necessarily indicative of the results to be expected for the full year ending December 31, 2020 . For further information, refer to the audited consolidated financial statements and footnotes thereto included in Fuel Tech’s Annual Report on Form 10-K for the year ended December 31, 2019 as filed with the Securities and Exchange Commission. COVID-19 Pandemic The emergence of the coronavirus (COVID-19) around the world presents significant risks to the Company, not all of which the Company is able to fully evaluate or even foresee at the current time. While the COVID-19 pandemic did not materially adversely affect the Company’s financial results and business operations in the Company’s first fiscal quarter ended March 31, 2020, economic and health conditions in the United States and across most of the globe have changed rapidly. The COVID-19 pandemic has affected the Company’s operations in the three and six months ended June 30, 2020, although the impact of the pandemic is difficult to quantify, and may continue to do so indefinitely thereafter. The Company has experienced, and may continue to experience, reductions in demand for certain of our products as several accounts remained offline due to soft electric demand and unplanned outage activities and due to the delay or abandonment of ongoing or anticipated projects due to our customers’, suppliers’ and other third parties’ financial distress or concern regarding the volatility of global markets. Management cannot predict the full impact of the COVID-19 pandemic on the Company’s sales and marketing channels and supply chain, and as a result, the ultimate extent of the effects of the COVID-19 pandemic on the Company is highly uncertain and will depend on future developments. Such effects could exist for an extended period of time even after the pandemic might end.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Restricted cash Restricted cash as of June 30, 2020 represents funds that are restricted to satisfy any amount borrowed against the Company's Cash Collateral Security agreement with BMO Harris Bank N.A. The balance of restricted cash totaling $3,003 is comprised of $2,639 in current assets relating to existing standby letters of credit with varying maturity dates and expire no later than June 30, 2021 and $364 in long-term assets will remain through the expiration dates of the underlying standby letter of credits (the latest maturity date is February 1, 2023) with BMO Harris Bank N.A. Refer to Note 9 Debt Financing for further information on the Cash Collateral Security agreement with BMO Harris Bank N.A. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows: June 30, June 30, Cash and cash equivalents $ 8,254 $ 11,664 Restricted cash included in current assets 2,639 2,768 Restricted cash included in long-term assets 364 487 Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 11,257 $ 14,919 Leases The Company applies the provisions of Accounting Standards Codification ("ASC") 842, Leases. The Company determines if an arrangement is a lease at inception by evaluating whether the arrangement conveys the right to use an identified asset and whether the Company obtains substantially all of the economic benefits from and has the ability to direct the use of the asset. Right-of-use ("ROU") assets and lease liabilities are recognized at the lease commencement date based on the present value of the future minimum lease payments over the lease term. Operating ROU assets also include the impact of any lease incentives. Operating leases are included in right-of-use ("ROU") operating lease assets, operating lease liabilities - current, and operating lease liabilities - non-current on our Consolidated Balance Sheets. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components, and we elected the practical expedient to not separate lease and non-lease components for the majority of our leases. For certain equipment leases, such as vehicles, we account for the lease and non-lease components as a single lease component. We also elected the practical expedient to keep leases with an initial term of 12 months or less off of the consolidated balance sheet.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The Company recognizes revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Fuel Tech’s sales of products to customers represent single performance obligations. The majority of our contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and, therefore, not distinct. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. Sales, value add, and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. We generally expense sales commissions on a ratable basis when incurred because the amortization period would have been one year or less. These costs are recorded within selling, general and administrative expenses within the Condensed Consolidated Statements of Operations. FUEL CHEM Revenues from the sale of chemical products are recognized when control transfers to customer upon shipment or delivery of the product based on the applicable shipping terms. We generally recognize revenue for these arrangements at a point in time based on our evaluation of when the customer obtains control of the promised goods or services. Air Pollution Control Technology Fuel Tech’s APC contracts are typically six to eighteen months in length. A typical contract will have three or four critical operational measurements that, when achieved, serve as the basis for us to invoice the customer via progress billings. At a minimum, these measurements will include the generation of engineering drawings, the shipment of equipment and the completion of a system performance test. As part of most of its contractual APC project agreements, Fuel Tech will agree to customer-specific acceptance criteria that relate to the operational performance of the system that is being sold. These criteria are determined based on modeling that is performed by Fuel Tech personnel, which is based on operational inputs that are provided by the customer. The customer will warrant that these operational inputs are accurate as they are specified in the binding contractual agreement. Further, the customer is solely responsible for the accuracy of the operating condition information; typically all performance guarantees and equipment warranties granted by us are voidable if the operating condition information is inaccurate or is not met. Since control transfers over time, revenue is recognized based on the extent of progress towards completion of the single performance obligation. Fuel Tech uses the cost-to-cost input measure of progress for our contracts since it best depicts the transfer of assets to the customer which occurs as we incur costs on our contracts. Under the cost-to-cost input measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. Revenues are recorded proportionally as costs are incurred. Costs to fulfill include all internal and external engineering costs, equipment charges, inbound and outbound freight expenses, internal and site transfer costs, installation charges, purchasing and receiving costs, inspection costs, warehousing costs, project personnel travel expenses and other direct and indirect expenses specifically identified as project- or product-line related, as appropriate (e.g. test equipment depreciation and certain insurance expenses). Fuel Tech’s APC product line also includes ancillary revenue for post contractual goods and services. Revenue associated with these activities are recognized at point in time when delivery of goods or completion of the service obligation is performed. Fuel Tech has installed over 1,100 units with APC technology and normally provides performance guarantees to our customers based on the operating conditions for the project. As part of the project implementation process, we perform system start-up and optimization services that effectively serve as a test of actual project performance. We believe that this test, combined with the accuracy of the modeling that is performed, enables revenue to be recognized prior to the receipt of formal customer acceptance. Disaggregated Revenue by Product Technology The following table presents our revenues disaggregated by product technology: Three Months Ended Six Months Ended 2020 2019 2020 2019 Air Pollution Control Technology solutions $ 1,469 $ 3,795 $ 2,198 $ 8,536 Spare parts 214 384 413 533 Ancillary revenue 254 624 522 1,523 Total Air Pollution Control Technology revenues 1,937 4,803 3,133 10,592 FUEL CHEM FUEL CHEM technology solutions 2,464 4,145 5,046 8,511 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103 Disaggregated Revenue by Geography The following table presents our revenues disaggregated by geography, based on the billing addresses of our customers: Three Months Ended Six Months Ended 2020 2019 2020 2019 United States $ 3,310 $ 7,562 $ 6,407 $ 16,377 Foreign Revenues Latin America 59 17 205 192 Europe 197 668 590 1,285 Asia 835 701 977 1,249 Total Foreign Revenues 1,091 1,386 1,772 2,726 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103 Timing of Revenue Recognition The following table presents the timing of our revenue recognition: Three Months Ended Six Months Ended 2020 2019 2020 2019 Products transferred at a point in time $ 2,932 $ 5,153 $ 5,981 $ 10,567 Products and services transferred over time 1,469 3,795 2,198 8,536 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103 Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the consolidated balance sheets. In our Air Pollution Control Technology segment, amounts are billed as work progresses in accordance with agreed-upon contractual terms. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. These assets are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. At June 30, 2020 and December 31, 2019 , contract assets were approximately $1,763 and $1,857 , respectively, and are included in accounts receivable on the consolidated balance sheets. However, the Company will periodically bill in advance of costs incurred before revenue is recognized, resulting in contract liabilities. These liabilities are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. Contract liabilities were $1,168 and $712 , at June 30, 2020 and December 31, 2019 , respectively, and are included in other accrued liabilities on the consolidated balance sheets. Changes in the contract asset and liability balances during the six month period ended June 30, 2020 , were not materially impacted by any other items other than amounts billed and revenue recognized as described previously. Revenue recognized that was included in the contract liability balance at the beginning of the period was $210 and $458 for the three and six months ended June 30, 2020 , respectively and $707 and $926 for three and six months ended June 30, 2019 , respectively, which represented primarily revenue from progress towards completion of our Air Pollution Control technology contracts. As of June 30, 2020 , we had three construction contracts in progress that were identified as loss contracts and a provision for losses of $16 was recorded in other accrued liabilities on the consolidated balance sheet. Refer to Footnote 13 for an accrual related to certain non-conformance issues with a U.S. customer associated with equipment that requires remedy under the warranty provision of the customer contract. As of December 31, 2019 , we had three construction contracts in progress that were identified as loss contracts and a provision for losses in the amount of $26 was recorded in other accrued liabilities on the consolidated balance sheet. Remaining Performance Obligations Remaining performance obligations, represents the transaction price of Air Pollution Control technology booked orders for which work has not been performed. As of June 30, 2020 , the aggregate amount of the transaction price allocated to remaining performance obligations was $8,321 . The Company expects to recognize revenue on approximately $4,845 of the remaining performance obligations over the next 12 months with the remaining recognized thereafter. Accounts Receivable The components of accounts receivable are as follows: As of June 30, 2020 December 31, 2019 Trade receivables $ 4,592 $ 6,425 Unbilled receivables 1,763 1,857 Other short-term receivables 19 7 Allowance for doubtful accounts (716 ) (1,816 ) Total accounts receivable $ 5,658 $ 6,473

Restructuring Activities

Restructuring Activities	6 Months Ended
	Jun. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring Activities	Restructuring Activities On January 18, 2019, the Company announced a planned suspension of its Air Pollution Control (“APC”) business operation in China. This action is part of Fuel Tech’s ongoing operational improvement initiatives designed to prioritize resource allocation, reduce costs, and drive profitability for the Company on a global basis. The transition associated with the suspension of the APC business which has taken place through June 30, 2020 includes staff rationalization and reduction, supplier and partner engagement, and the monetization of certain assets. The remaining transition activities include the execution of the remaining activities to satisfy the requirements for the remaining APC projects in China (with a backlog totaling approximately $29 ) in addition to collection efforts for the remaining accounts receivable. The following table presents our revenues and net loss (which includes the Restructuring charge line item within the Condensed Statements of Operations for 2020 and 2019 in China as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Total revenues $ 3 $ (28 ) $ 5 $ 310 Net income (loss) (85 ) (540 ) 42 (1,390 ) Total assets primarily consist of cash, accounts receivable, contract assets, prepaid expenses and other current assets. Total liabilities consist of accounts payable and certain accrued liabilities. The following table presents net assets in China as follows: As of June 30, 2020 December 31, 2019 Total assets $ 3,072 $ 4,249 Total liabilities 352 399 Total net assets $ 2,720 $ 3,850 The Company incurred $0 in the three and six month periods ending June 30, 2020 and $30 and $625 during the three and six month periods ending June 30, 2019 for severance and lease cancellation costs related to the suspension of the APC business in China. There is no liability for restructuring activities for the three and six months ending June 30, 2020 . The following is a reconciliation of the accrual for the workforce reduction that is included within the "Accrued Liabilities - Employee Compensation" line of the consolidated balance sheets for the three and six months ending June 30, 2020 and 2019 : Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Restructuring liability at beginning of period $ — $ 373 $ — $ 65 Amounts expensed — 30 — 625 Amounts paid — (248 ) — (535 ) Restructuring liability at end of period $ — $ 155 $ — $ 155

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The changes in accumulated other comprehensive loss by component were as follows: Three months ended June 30, Six Months Ended 2020 2019 2020 2019 Foreign currency translation Balance at beginning of period $ (2,009 ) $ (1,181 ) $ (1,778 ) $ (1,285 ) Other comprehensive loss: Foreign currency translation adjustments (1) 152 (43 ) (79 ) 61 Total accumulated other comprehensive loss $ (1,857 ) $ (1,224 ) $ (1,857 ) $ (1,224 ) (1) In all periods presented, there were no tax impacts related to rate changes and no amounts were reclassified to earnings.

Treasury Stock

Treasury Stock	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Treasury Stock	Treasury Stock Common stock held in treasury totaled 808,139 and 796,090 with a cost of $1,618 and $1,612 at June 30, 2020 and December 31, 2019 , respectively. These shares were withheld from employees to settle personal tax withholding obligations that arose as a result of restricted stock units that vested in the periods presented.

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic earnings per share excludes the dilutive effects of stock options, restricted stock units (RSUs), and the nil coupon non-redeemable convertible unsecured loan notes. Diluted earnings per share includes the dilutive effect of the nil coupon non-redeemable convertible unsecured loan notes, RSUs, and unexercised in-the-money stock options, except in periods of net loss where the effect of these instruments is anti-dilutive. Out-of-money stock options are excluded from diluted earnings per share because they are anti-dilutive. For the three and six months ended June 30, 2020 and 2019, basic earnings per share is equal to diluted earnings per share because all outstanding stock awards and convertible loan notes are considered anti-dilutive during periods of net loss. The following table sets forth the weighted-average shares used in calculating the earnings per share for the three and six months ended June 30, 2020 and 2019 . Three Months Ended Six Months Ended 2020 2019 2020 2019 Basic weighted-average shares 24,668,000 24,187,000 24,633,000 24,182,000 Conversion of unsecured loan notes — — — — Unexercised options and unvested RSUs — — — — Diluted weighted-average shares 24,668,000 24,187,000 24,633,000 24,182,000 Fuel Tech had 553,000 and 1,515,000 weighted average equity awards outstanding at June 30, 2020 and 2019 , respectively, that were not dilutive for the purposes of inclusion in the calculation of diluted earnings per share but could potentially become dilutive in future periods.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Under our stock-based employee compensation plan, referred to as the Fuel Tech, Inc. 2014 Long-Term Incentive Plan (Incentive Plan), awards may be granted to participants in the form of Non-Qualified Stock Options, Incentive Stock Options, Stock Appreciation Rights, Restricted Stock, Restricted Stock Units (“RSUs”), Performance Awards, Bonuses or other forms of share-based or non-share-based awards or combinations thereof. Participants in the Incentive Plan may be our directors, officers, employees, consultants or advisors (except consultants or advisors in capital-raising transactions) as the directors determine are key to the success of our business. There are a maximum of 5,600,676 shares that may be issued or reserved for awards to participants under the Incentive Plan. As of June 30, 2020 , Fuel Tech had 2,284,333 shares available for share-based awards under the 2014 Plan. We did not record any excess tax benefits within income tax expense for the three and six months ended June 30, 2020 . Given the Company has a full valuation allowance on its deferred tax assets, there were no excess tax benefits to record for the three and six months ended June 30, 2020 . In addition, we account for forfeitures of awards based on an estimate of the number of awards expected to be forfeited and adjusting the estimate when it is no longer probable that the employee will fulfill the service condition. Stock-based compensation is included in selling, general, and administrative costs in our Consolidated Statements of Operations. The components of stock-based compensation for the three and six months ended June 30, 2020 and 2019 were as follows: Three Months Ended Six Months Ended June 30, 2020 2019 2020 2019 Stock options and restricted stock units, net of forfeited $ 69 $ 123 $ 150 $ 219 Tax benefit of stock-based compensation expense — — — — After-tax effect of stock-based compensation $ 69 $ 123 $ 150 $ 219 Stock Options Stock options granted to employees under the Incentive Plans have a 10 -year life and they vest as follows: 50% after the second anniversary of the award date, 25% after the third anniversary, and the final 25% after the fourth anniversary of the award date. Fuel Tech calculates stock compensation expense for employee option awards based on the grant date fair value of the award, less expected annual forfeitures, and recognizes expense on a straight-line basis over the four -year service period of the award. Stock options granted to members of our board of directors vest immediately. Stock compensation for these awards is based on the grant date fair value of the award and is recognized in expense immediately. Fuel Tech uses the Black-Scholes option pricing model to estimate the grant date fair value of employee stock options. The principal variable assumptions utilized in valuing options and the methodology for estimating such model inputs include: (1) risk-free interest rate – an estimate based on the yield of zero–coupon treasury securities with a maturity equal to the expected life of the option; (2) expected volatility – an estimate based on the historical volatility of Fuel Tech’s Common Stock for a period equal to the expected life of the option; and (3) expected life of the option – an estimate based on historical experience including the effect of employee terminations. Stock option activity for Fuel Tech’s Incentive Plans for the six months ended June 30, 2020 was as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding on January 1, 2020 747,500 $ 3.33 Granted — — Exercised — — Expired or forfeited (40,000 ) 5.50 Outstanding on June 30, 2020 707,500 $ 3.21 4.48 $ — Exercisable on June 30, 2020 707,500 $ 3.21 4.48 $ — As of June 30, 2020 , there was no unrecognized compensation cost related to non-vested stock options granted under the Incentive Plans. Restricted Stock Units Restricted stock units (RSUs) granted to employees vest over time based on continued service (typically vesting over a period between two and four years). Such time-vested RSUs are valued at the date of grant using the intrinsic value method based on the closing price of the Common Shares on the grant date. Compensation cost, adjusted for estimated forfeitures, is amortized on a straight-line basis over the requisite service period. In addition to the time vested RSUs, the Company entered into a 2020 Executive Performance RSU Award Agreement (the “2020 Agreement”) with certain officers, including its President and Chief Executive Officer pursuant to which each 2020 Participating Executive will have the opportunity to earn a specified amount of restricted stock units (RSUs). The amount of RSUs awarded, if any, will be based on the Company’s achievement of varying levels of operating income before the impact of incentive pay (but including adjustments to reflect the payment of sales commissions) in fiscal 2020 (“Operating Income”), as determined by the Company, in its sole discretion. Nevertheless, no Participating Executive will be entitled to any such RSUs unless the Company achieves a minimum of $1 million in Operating Income in 2020. If awarded, such RSUs will vest in equal amounts ( i.e., 1/3, 1/3 and 1/3) over three years commencing one year after the grant date based on continued service. Such RSUs are valued at the date of grant using the intrinsic value method based on the closing price of the Company’s common stock on the grant date. At June 30, 2020 , there is $208 of unrecognized compensation cost related to all non-vested share-based compensation arrangements granted under the Incentive Plan. That cost is expected to be recognized over the remaining requisite service period of 1.32 years. A summary of restricted stock unit activity for the six months ended June 30, 2020 is as follows: Shares Weighted Average Grant Date Fair Value Unvested restricted stock units at January 1, 2020 775,635 $ 1.47 Granted — — Forfeited (25,000 ) 0.97 Vested (120,630 ) 1.57 Unvested restricted stock units at June 30, 2020 630,005 $ 1.47 The fair value of restricted stock that vested during the six month period ending June 30, 2020 was $190 . Deferred Directors Fees In addition to the Incentive Plans, Fuel Tech has a Deferred Compensation Plan for Directors (Deferred Plan). Under the terms of the Deferred Plan, Directors can elect to defer Directors’ fees for shares of Fuel Tech Common Stock that are issuable at a future date as defined in the agreement. In accordance with ASC 718, Fuel Tech accounts for these awards as equity awards as opposed to liability awards. During the six month periods ended June 30, 2020 and 2019 , Fuel Tech recorded no stock-based compensation expense under the Deferred Plan.

Debt Financing

Debt Financing	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Debt Financing	Debt Financing On April 17, 2020, the Company received $1,556 in loan proceeds from the Paycheck Protection Program (the “PPP”), established pursuant to the recently enacted Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) and administered by the U.S. Small Business Administration (“SBA”). The unsecured loan is evidenced by a promissory note of the Company dated April 15, 2020 (the “Note”) in the principal amount of $1,556 , issued to BMO Harris Bank N.A. (the “Bank”), the lender. Under the terms of the Note, interest will accrue on the outstanding principal at the rate of 1.0% per annum. The term of the Note is two years , though it may be payable sooner in connection with an event of default under the Note. To the extent the loan amount is not forgiven under the PPP, the Company is obligated to make equal monthly payments of principal and interest, beginning seven months from the date of the Note, until the maturity date. The Note contains covenants by the Company, including obtaining the written consent of the Bank prior to material changes in the management or ownership of the Company. On June 19, 2019, the Company entered into a Cash Collateral Security agreement with BMO Harris Bank, N.A. (the BMO Harris agreement) to use for the sole purpose of issuing standby letters of credit. The BMO Harris agreement requires us to pledge as cash collateral 105% of the aggregate face amount of outstanding standby letters of credit. The Company pays 250 basis points on the face values of outstanding letters of credit. There are no financial covenants set forth in the BMO Harris agreement. At June 30, 2020 and December 31, 2019, respectively, the Company had outstanding standby letters of credit totaling approximately $2,860 and $2,461 under the BMO Harris agreement. As of June 30, 2020 and December 31, 2019 respectively, the Company held $3,003 and $2,584 in a separate restricted use designated BMO Harris Bank N.A. deposit account. Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments. In connection with the transition to BMO Harris Bank N.A., the Company canceled its U.S. credit facility with JPMorgan Chase Bank, N.A. effective on September 25, 2019.

Business Segment and Geographic

Business Segment and Geographic Financial Data	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Business Segment and Geographic Financial Data	Business Segment and Geographic Financial Data Business Segment Financial Data We segregate our financial results into two reportable segments representing two broad technology segments as follows: • The Air Pollution Control technology segment includes technologies to reduce NO x emissions in flue gas from boilers, incinerators, furnaces and other stationary combustion sources. These include Low and Ultra Low NO x Burners (LNB and ULNB), Over-Fire Air (OFA) systems, NO x OUT ® and HERT™ Selective Non-Catalytic Reduction (SNCR) systems, and Advanced Selective Catalytic Reduction (ASCR ™ ) systems. Our ASCR systems include ULNB, OFA, and SNCR components, along with a downsized SCR catalyst, Ammonia Injection Grid (AIG), and Graduated Straightening Grid GSG™ systems to provide high NO x reductions at significantly lower capital and operating costs than conventional SCR systems. The NO x OUT CASCADE ® and NO x OUT-SCR ® processes are more basic, using just SNCR and SCR catalyst components. ULTRA™ technology creates ammonia at a plant site using safe urea for use with any SCR application. Flue Gas Conditioning systems are chemical injection systems offered in markets outside the U.S. and Canada to enhance electrostatic precipitator and fabric filter performance in controlling particulate emissions. • The FUEL CHEM ® technology segment, which uses chemical processes in combination with advanced CFD and CKM boiler modeling, for the control of slagging, fouling, corrosion, opacity and other sulfur trioxide-related issues in furnaces and boilers through the addition of chemicals into the furnace using TIFI ® Targeted In-Furnace Injection™ technology. The “Other” classification includes those profit and loss items not allocated to either reportable segment. There are no inter-segment sales that require elimination. We evaluate performance and allocate resources based on reviewing gross margin by reportable segment. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies (Note 1 in our annual report on Form 10-K). We do not review assets by reportable segment, but rather, in aggregate for the Company as a whole. Information about reporting segment net sales and gross margin from continuing operations are provided below: Three months ended June 30, 2020 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 1,937 $ 2,464 $ — $ 4,401 Cost of sales (2,320 ) (1,479 ) — (3,799 ) Gross margin (383 ) 985 — 602 Selling, general and administrative — — (2,755 ) (2,755 ) Research and development — — (271 ) (271 ) Operating (loss) income from continuing operations $ (383 ) $ 985 $ (3,026 ) $ (2,424 ) ` Three months ended June 30, 2019 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 4,803 $ 4,145 $ — $ 8,948 Cost of sales (2,975 ) (2,075 ) — (5,050 ) Gross margin 1,828 2,070 — 3,898 Selling, general and administrative — — (4,455 ) (4,455 ) Restructuring Charge (30 ) — — (30 ) Research and development — — (205 ) (205 ) Intangible assets abandonment — — (51 ) (51 ) Operating income (loss) from continuing operations $ 1,798 $ 2,070 $ (4,711 ) $ (843 ) Six months ended June 30, 2020 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 3,133 $ 5,046 $ — $ 8,179 Cost of sales (3,086 ) (2,964 ) — (6,050 ) Gross margin 47 2,082 — 2,129 Selling, general and administrative — — (6,641 ) (6,641 ) Research and development — — (595 ) (595 ) Operating (loss) income from continuing operations $ 47 $ 2,082 $ (7,236 ) $ (5,107 ) ` Six months ended June 30, 2019 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 10,592 $ 8,511 $ — $ 19,103 Cost of sales (6,864 ) (4,327 ) — (11,191 ) Gross margin 3,728 4,184 — 7,912 Selling, general and administrative — — (8,913 ) (8,913 ) Restructuring Charge (625 ) — — (625 ) Research and development — — (471 ) (471 ) Intangible assets abandonment — — (51 ) (51 ) Operating income (loss) from continuing operations $ 3,103 $ 4,184 $ (9,435 ) $ (2,148 ) Geographic Segment Financial Data Information concerning our operations by geographic area is provided below. Revenues are attributed to countries based on the location of the customer. Assets are those directly associated with operations of the geographic area. Three Months Ended Six Months Ended June 30, 2020 2019 2020 2019 Revenues: United States $3,310 $7,562 $6,407 $16,377 Foreign 1,091 1,386 1,772 2,726 $4,401 $8,948 $8,179 $19,103 June 30, December 31, Assets: United States $ 22,090 $ 23,460 Foreign 6,467 8,764 $ 28,557 $ 32,224

Leases

Leases	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	Leases Leases We have seven total operating leases which relate to both office space locations and certain office equipment. Our leases have remaining lease terms of 11 months to 5 years. Our leases do not contain any material residual value guarantees or material restricted covenants and we currently have no material sublease arrangements. We have no financing leases as defined under ASC 842. Total operating lease expense for the three and six months ended June 30, 2020 and 2019 is as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Operating lease cost $ 79 $ 171 $ 167 $ 343 Short-term lease cost 4 — 7 68 Total lease cost $ 83 $ 171 $ 174 $ 411 The weighted average remaining lease term was 4.20 years as of June 30, 2020 . The weighted average discount rate was 3.62% as of June 30, 2020 . Remaining maturities of our existing lease liabilities as of June 30, 2020 were as follows: Year Ending December 31, Operating Leases 2020 (excluding the six months ended June 30, 2020) 152 2021 303 2022 249 2023 242 Thereafter 206 Total lease payments $ 1,152 Less imputed interest (135 ) Total $ 1,017 The following is the balance sheet classification of our existing lease liabilities as of June 30, 2020 : As of June 30, 2020 December 31, 2019 Operating lease liabilities - current $ 279 $ 300 Operating lease liabilities - non-current 738 680 Total operating lease liabilities $ 1,017 $ 980 Supplemental cash flow information related to leases was as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Cash paid for amounts included in the measurement of lease liabilities $ 84 $ 172 $ 175 $ 343 Leased assets obtained in exchange for operating lease liabilities 74 165 155 328

Accrued Liabilities

Accrued Liabilities	6 Months Ended
	Jun. 30, 2020
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities The components of other accrued liabilities are as follows: As of June 30, 2020 December 31, 2019 Contract liabilities (Note 3) $ 1,168 $ 712 Accrued remediation contingency (Note 13) — 146 Other accrued liabilities 936 1,118 Total other accrued liabilities $ 2,104 $ 1,976

Contingencies

Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Commitments and Contingencies Fuel Tech is subject to various claims and contingencies related to, among other things, workers compensation, general liability (including product liability), and lawsuits. The Company records liabilities where a contingent loss is probable and can be reasonably estimated. If the reasonable estimate of a probable loss is a range, the Company records the most probable estimate of the loss or the minimum amount when no amount within the range is a better estimate than any other amount. The Company discloses a contingent liability even if the liability is not probable or the amount is not estimable, or both, if there is a reasonable possibility that a material loss may have been incurred. From time to time we are involved in litigation with respect to matters arising from the ordinary conduct of our business. In the opinion of management, based upon presently available information, either adequate provision for anticipated costs have been accrued or the ultimate anticipated costs will not materially affect our consolidated financial position, results of operations, or cash flows. We do not believe we have any pending loss contingencies that are probable or reasonably possible of having a material impact on our consolidated financial position, results of operations or cash flows. During the fourth quarter of 2018, the Company was notified of certain non-conformance issues with a U.S. customer associated with equipment that requires remedy under the warranty provision of the contract. During the second quarter of 2020 a charge of $1,150 to remedy this non-conformance issue was incurred. Offsetting this amount was a reversal of $499 of expense to reduce the allowance of doubtful accounts that had been previously reserved. The Company has completed all work associated with this issue. As of June 30, 2020 and December 31, 2019, we have $0 and $146 of accrued liability associated with the completion of the non-conformance issues in the other accrued liabilities line of the Consolidated Balance Sheets. Fuel Tech issues a standard product warranty with the sale of its products to customers. Our recognition of warranty liability is based primarily on analyses of warranty claims experienced in the preceding years as the nature of our historical product sales for which we offer a warranty are substantially unchanged. This approach provides an aggregate warranty accrual that is historically aligned with actual warranty claims experienced. There was no change in the warranty liability balance included in the other accrued liabilities line of the Consolidated Balance Sheets during the six months ended June 30, 2020 and 2019 . The warranty liability balance was $159 at June 30, 2020 and 2019 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate is approximately 3% and 0% for the six-month period ended June 30, 2020 and 2019 , respectively. The Company's effective tax rate differs from the statutory federal tax rate of 21% for the six month period ended June 30, 2020 primarily due to a full valuation allowance recorded on our United States, China and Italy deferred tax assets since we cannot anticipate when or if we will have sufficient taxable income to utilize the deferred tax assets in the future. Further, our effective tax rate differs from the statutory federal tax rate due to state taxes, differences between U.S. and foreign tax rates, foreign losses incurred with no related tax benefit, non-deductible commissions, and non-deductible meals and entertainment expenses for the six month periods ended June 30, 2020 and 2019 . Fuel Tech had no unrecognized tax benefits as of June 30, 2020 and December 31, 2019 . On March 27, 2020, President Trump signed into law the Coronavirus Aid, Relief, and Economic Security Act (H.R. 748) (the “CARES Act”). Among the changes to the U.S. federal income tax rules, the Cares Act restored net operating loss carryback rules that were eliminated by 2017 Tax Cuts and Jobs Act, restored 100 percent bonus depreciation for qualified improvement property, modified the limit on the deduction for net interest expense and accelerated the timeframe for refunds of AMT credits. At this time we do not anticipate a material impact to the Company’s current or deferred income taxes as a result of the CARES Act. We will continue to evaluate the effects of the CARES Act as additional legislative guidance become available.

Goodwill and Other Intangibles

Goodwill and Other Intangibles	6 Months Ended
	Jun. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangibles	Goodwill and Other Intangibles Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment. Fuel Tech has two reporting units for goodwill evaluation purposes: the FUEL CHEM ® technology segment and the APC technology segment. There is no goodwill associated with our APC segment. At both June 30, 2020 and December 31, 2019 , our entire goodwill balance of $2,116 was allocated to the FUEL CHEM ® technology segment. Goodwill is allocated to each of our reporting units after considering the nature of the net assets giving rise to the goodwill and how each reporting unit would enjoy the benefits and synergies of the net assets acquired. There were no indications of goodwill impairment in the six months ended June 30, 2020 and 2019 . Fuel Tech reviews other intangible assets, which include patent assets, for impairment on a recurring basis or when events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. In the event that impairment indicators exist, a further analysis is performed and if the sum of the expected undiscounted future cash flows resulting from the use of the asset is less than the carrying amount of the asset, an impairment loss equal to the excess of the asset’s carrying value over its fair value is recorded. Management considers historical experience and all available information at the time the estimates of future cash flows are made, however, the actual cash values that could be realized may differ from those that are estimated. There were no indications of intangible asset impairments for the six month periods ended June 30, 2020 and 2019 .

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated subsequent events through the filing of this Quarterly Report on Form 10-Q, and determined that there have been no events that have occurred that would require adjustments to our disclosures in the consolidated financial statements.

Liquidity

Liquidity	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Liquidity	Liquidity We continue to monitor our liquidity needs and in response to our continued losses have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We have experienced continued declines in revenues and recurring losses. As a result, we have evaluated our ongoing business needs, and considered the cash requirements of our base business of Air Pollution Control (APC) and Fuel Chem businesses. This evaluation included consideration of the following: a) customer and revenue trends in our APC and Fuel Chem business segments, b) current operating structure and expenditure levels, c) current availability of working capital, and d) support for our research and development initiatives. We continue to monitor our liquidity needs and have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We believe our current cash position and net cash flows expected to be generated from operations are adequate to fund planned operations of the Company for the next 12 months. In the event we determine we need to raise additional working capital, we may consider various financing alternatives which may include debt financing, common stock offerings, or financing involving convertible debt or other equity-linked securities; however, such financing alternatives may not be available on acceptable terms or at all and any such additional financing could be dilutive to our shareholders.

General (Policies)

General (Policies)	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, the financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the statements for the periods presented. All significant intercompany transactions and balances have been eliminated. The results of operations for the three and six months ended June 30, 2020 are not necessarily indicative of the results to be expected for the full year ending December 31, 2020 . For further information, refer to the audited consolidated financial statements and footnotes thereto included in Fuel Tech’s Annual Report on Form 10-K for the year ended December 31, 2019 as filed with the Securities and Exchange Commission.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
New Accounting Pronouncements	Leases The Company applies the provisions of Accounting Standards Codification ("ASC") 842, Leases. The Company determines if an arrangement is a lease at inception by evaluating whether the arrangement conveys the right to use an identified asset and whether the Company obtains substantially all of the economic benefits from and has the ability to direct the use of the asset. Right-of-use ("ROU") assets and lease liabilities are recognized at the lease commencement date based on the present value of the future minimum lease payments over the lease term. Operating ROU assets also include the impact of any lease incentives. Operating leases are included in right-of-use ("ROU") operating lease assets, operating lease liabilities - current, and operating lease liabilities - non-current on our Consolidated Balance Sheets. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components, and we elected the practical expedient to not separate lease and non-lease components for the majority of our leases. For certain equipment leases, such as vehicles, we account for the lease and non-lease components as a single lease component. We also elected the practical expedient to keep leases with an initial term of 12 months or less off of the consolidated balance sheet.
Revenue Recognition	The Company recognizes revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. Fuel Tech’s sales of products to customers represent single performance obligations. The majority of our contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and, therefore, not distinct. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. Sales, value add, and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. We generally expense sales commissions on a ratable basis when incurred because the amortization period would have been one year or less. These costs are recorded within selling, general and administrative expenses within the Condensed Consolidated Statements of Operations. FUEL CHEM Revenues from the sale of chemical products are recognized when control transfers to customer upon shipment or delivery of the product based on the applicable shipping terms. We generally recognize revenue for these arrangements at a point in time based on our evaluation of when the customer obtains control of the promised goods or services. Air Pollution Control Technology Fuel Tech’s APC contracts are typically six to eighteen months in length. A typical contract will have three or four critical operational measurements that, when achieved, serve as the basis for us to invoice the customer via progress billings. At a minimum, these measurements will include the generation of engineering drawings, the shipment of equipment and the completion of a system performance test. As part of most of its contractual APC project agreements, Fuel Tech will agree to customer-specific acceptance criteria that relate to the operational performance of the system that is being sold. These criteria are determined based on modeling that is performed by Fuel Tech personnel, which is based on operational inputs that are provided by the customer. The customer will warrant that these operational inputs are accurate as they are specified in the binding contractual agreement. Further, the customer is solely responsible for the accuracy of the operating condition information; typically all performance guarantees and equipment warranties granted by us are voidable if the operating condition information is inaccurate or is not met. Since control transfers over time, revenue is recognized based on the extent of progress towards completion of the single performance obligation. Fuel Tech uses the cost-to-cost input measure of progress for our contracts since it best depicts the transfer of assets to the customer which occurs as we incur costs on our contracts. Under the cost-to-cost input measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. Revenues are recorded proportionally as costs are incurred. Costs to fulfill include all internal and external engineering costs, equipment charges, inbound and outbound freight expenses, internal and site transfer costs, installation charges, purchasing and receiving costs, inspection costs, warehousing costs, project personnel travel expenses and other direct and indirect expenses specifically identified as project- or product-line related, as appropriate (e.g. test equipment depreciation and certain insurance expenses). Fuel Tech’s APC product line also includes ancillary revenue for post contractual goods and services. Revenue associated with these activities are recognized at point in time when delivery of goods or completion of the service obligation is performed. Fuel Tech has installed over 1,100 units with APC technology and normally provides performance guarantees to our customers based on the operating conditions for the project. As part of the project implementation process, we perform system start-up and optimization services that effectively serve as a test of actual project performance. We believe that this test, combined with the accuracy of the modeling that is performed, enables revenue to be recognized prior to the receipt of formal customer acceptance.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents, and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows: June 30, June 30, Cash and cash equivalents $ 8,254 $ 11,664 Restricted cash included in current assets 2,639 2,768 Restricted cash included in long-term assets 364 487 Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 11,257 $ 14,919

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents the timing of our revenue recognition: Three Months Ended Six Months Ended 2020 2019 2020 2019 Products transferred at a point in time $ 2,932 $ 5,153 $ 5,981 $ 10,567 Products and services transferred over time 1,469 3,795 2,198 8,536 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103 The following table presents our revenues disaggregated by product technology: Three Months Ended Six Months Ended 2020 2019 2020 2019 Air Pollution Control Technology solutions $ 1,469 $ 3,795 $ 2,198 $ 8,536 Spare parts 214 384 413 533 Ancillary revenue 254 624 522 1,523 Total Air Pollution Control Technology revenues 1,937 4,803 3,133 10,592 FUEL CHEM FUEL CHEM technology solutions 2,464 4,145 5,046 8,511 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103
Revenue Disaggregated by Geography	The following table presents our revenues disaggregated by geography, based on the billing addresses of our customers: Three Months Ended Six Months Ended 2020 2019 2020 2019 United States $ 3,310 $ 7,562 $ 6,407 $ 16,377 Foreign Revenues Latin America 59 17 205 192 Europe 197 668 590 1,285 Asia 835 701 977 1,249 Total Foreign Revenues 1,091 1,386 1,772 2,726 Total Revenues $ 4,401 $ 8,948 $ 8,179 $ 19,103
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	The components of accounts receivable are as follows: As of June 30, 2020 December 31, 2019 Trade receivables $ 4,592 $ 6,425 Unbilled receivables 1,763 1,857 Other short-term receivables 19 7 Allowance for doubtful accounts (716 ) (1,816 ) Total accounts receivable $ 5,658 $ 6,473

Restructuring Activities (Table

Restructuring Activities (Tables)	6 Months Ended
	Jun. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring	The following table presents our revenues and net loss (which includes the Restructuring charge line item within the Condensed Statements of Operations for 2020 and 2019 in China as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Total revenues $ 3 $ (28 ) $ 5 $ 310 Net income (loss) (85 ) (540 ) 42 (1,390 ) The following table presents net assets in China as follows: As of June 30, 2020 December 31, 2019 Total assets $ 3,072 $ 4,249 Total liabilities 352 399 Total net assets $ 2,720 $ 3,850
Reconciliation of restructuring accrual	The following is a reconciliation of the accrual for the workforce reduction that is included within the "Accrued Liabilities - Employee Compensation" line of the consolidated balance sheets for the three and six months ending June 30, 2020 and 2019 : Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Restructuring liability at beginning of period $ — $ 373 $ — $ 65 Amounts expensed — 30 — 625 Amounts paid — (248 ) — (535 ) Restructuring liability at end of period $ — $ 155 $ — $ 155

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in accumulated other comprehensive loss by component were as follows: Three months ended June 30, Six Months Ended 2020 2019 2020 2019 Foreign currency translation Balance at beginning of period $ (2,009 ) $ (1,181 ) $ (1,778 ) $ (1,285 ) Other comprehensive loss: Foreign currency translation adjustments (1) 152 (43 ) (79 ) 61 Total accumulated other comprehensive loss $ (1,857 ) $ (1,224 ) $ (1,857 ) $ (1,224 ) (1) In all periods presented, there were no tax impacts related to rate changes and no amounts were reclassified to earnings.

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the weighted-average shares used in calculating the earnings per share for the three and six months ended June 30, 2020 and 2019 . Three Months Ended Six Months Ended 2020 2019 2020 2019 Basic weighted-average shares 24,668,000 24,187,000 24,633,000 24,182,000 Conversion of unsecured loan notes — — — — Unexercised options and unvested RSUs — — — — Diluted weighted-average shares 24,668,000 24,187,000 24,633,000 24,182,000

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	The components of stock-based compensation for the three and six months ended June 30, 2020 and 2019 were as follows: Three Months Ended Six Months Ended June 30, 2020 2019 2020 2019 Stock options and restricted stock units, net of forfeited $ 69 $ 123 $ 150 $ 219 Tax benefit of stock-based compensation expense — — — — After-tax effect of stock-based compensation $ 69 $ 123 $ 150 $ 219
Schedule of Stock Option Activity	Stock option activity for Fuel Tech’s Incentive Plans for the six months ended June 30, 2020 was as follows: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding on January 1, 2020 747,500 $ 3.33 Granted — — Exercised — — Expired or forfeited (40,000 ) 5.50 Outstanding on June 30, 2020 707,500 $ 3.21 4.48 $ — Exercisable on June 30, 2020 707,500 $ 3.21 4.48 $ —
Schedule of Nonvested Restricted Stock Units Activity	A summary of restricted stock unit activity for the six months ended June 30, 2020 is as follows: Shares Weighted Average Grant Date Fair Value Unvested restricted stock units at January 1, 2020 775,635 $ 1.47 Granted — — Forfeited (25,000 ) 0.97 Vested (120,630 ) 1.57 Unvested restricted stock units at June 30, 2020 630,005 $ 1.47

Business Segment and Geograph_2

Business Segment and Geographic Financial Data (Tables)	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Information about reporting segment net sales and gross margin from continuing operations are provided below: Three months ended June 30, 2020 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 1,937 $ 2,464 $ — $ 4,401 Cost of sales (2,320 ) (1,479 ) — (3,799 ) Gross margin (383 ) 985 — 602 Selling, general and administrative — — (2,755 ) (2,755 ) Research and development — — (271 ) (271 ) Operating (loss) income from continuing operations $ (383 ) $ 985 $ (3,026 ) $ (2,424 ) ` Three months ended June 30, 2019 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 4,803 $ 4,145 $ — $ 8,948 Cost of sales (2,975 ) (2,075 ) — (5,050 ) Gross margin 1,828 2,070 — 3,898 Selling, general and administrative — — (4,455 ) (4,455 ) Restructuring Charge (30 ) — — (30 ) Research and development — — (205 ) (205 ) Intangible assets abandonment — — (51 ) (51 ) Operating income (loss) from continuing operations $ 1,798 $ 2,070 $ (4,711 ) $ (843 ) Six months ended June 30, 2020 Air Pollution FUEL CHEM Other Total Revenues from external customers $ 3,133 $ 5,046 $ — $ 8,179 Cost of sales (3,086 ) (2,964 ) — (6,050 ) Gross margin 47 2,082 — 2,129 Selling, general and administrative — — (6,641 ) (6,641 ) Research and development — — (595 ) (595 ) Operating (loss) income from continuing operations $ 47 $ 2,082 $ (7,236 ) $ (5,107 )
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area	Information concerning our operations by geographic area is provided below. Revenues are attributed to countries based on the location of the customer. Assets are those directly associated with operations of the geographic area. Three Months Ended Six Months Ended June 30, 2020 2019 2020 2019 Revenues: United States $3,310 $7,562 $6,407 $16,377 Foreign 1,091 1,386 1,772 2,726 $4,401 $8,948 $8,179 $19,103
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country	June 30, December 31, Assets: United States $ 22,090 $ 23,460 Foreign 6,467 8,764 $ 28,557 $ 32,224

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Schedule of Lease Costs	Supplemental cash flow information related to leases was as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Cash paid for amounts included in the measurement of lease liabilities $ 84 $ 172 $ 175 $ 343 Leased assets obtained in exchange for operating lease liabilities 74 165 155 328 Total operating lease expense for the three and six months ended June 30, 2020 and 2019 is as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Operating lease cost $ 79 $ 171 $ 167 $ 343 Short-term lease cost 4 — 7 68 Total lease cost $ 83 $ 171 $ 174 $ 411 Supplemental cash flow information related to leases was as follows: Three Months Ended Six Months Ended 2020 2019 2020 2019 Cash paid for amounts included in the measurement of lease liabilities $ 84 $ 172 $ 175 $ 343 Leased assets obtained in exchange for operating lease liabilities 74 165 155 328
Assets And Liabilities, Lessee	The following is the balance sheet classification of our existing lease liabilities as of June 30, 2020 : As of June 30, 2020 December 31, 2019 Operating lease liabilities - current $ 279 $ 300 Operating lease liabilities - non-current 738 680 Total operating lease liabilities $ 1,017 $ 980
Lessee, Operating Lease, Liability, Maturity	Remaining maturities of our existing lease liabilities as of June 30, 2020 were as follows: Year Ending December 31, Operating Leases 2020 (excluding the six months ended June 30, 2020) 152 2021 303 2022 249 2023 242 Thereafter 206 Total lease payments $ 1,152 Less imputed interest (135 ) Total $ 1,017

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2020
Payables and Accruals [Abstract]
Schedule of other accrued liabilities	The components of other accrued liabilities are as follows: As of June 30, 2020 December 31, 2019 Contract liabilities (Note 3) $ 1,168 $ 712 Accrued remediation contingency (Note 13) — 146 Other accrued liabilities 936 1,118 Total other accrued liabilities $ 2,104 $ 1,976

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	$ 3,003
Cash and cash equivalents	8,254	$ 10,914	$ 11,664
Restricted cash included in current assets	2,639	2,080	2,768
Restricted cash included in long-term assets	364	507	487
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	11,257	$ 13,501	$ 14,919	$ 18,059
Restricted Until Maturity Date
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	2,639
Restricted Until Expiration of Agreement December 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Balance of total restricted cash	$ 364

Revenue - Additional Informatio

Revenue - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)contract	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)contractunit	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)contract
Revenue from Contract with Customer [Abstract]
Number of units installed (over) | unit			1,100
Unbilled receivables, current	$ 1,763		$ 1,763		$ 1,857
Contract liabilities	1,168		1,168		$ 712
Revenue recognized, included in contract liability balance	$ 210	$ 707	$ 458	$ 926
Number of contracts identified as loss contracts | contract	3		3		3
Provision for losses on contracts	$ 16		$ 16		$ 26

Revenue - Revenues Disaggregate

Revenue - Revenues Disaggregated by Product Technology (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
Air Pollution Control
Disaggregation of Revenue [Line Items]
Total Revenues	1,937	4,803	3,133	10,592
Air Pollution Control | Technology solutions
Disaggregation of Revenue [Line Items]
Total Revenues	1,469	3,795	2,198	8,536
Air Pollution Control | Spare parts
Disaggregation of Revenue [Line Items]
Total Revenues	214	384	413	533
Air Pollution Control | Ancillary revenue
Disaggregation of Revenue [Line Items]
Total Revenues	254	624	522	1,523
FUEL CHEM
Disaggregation of Revenue [Line Items]
Total Revenues	2,464	4,145	5,046	8,511
FUEL CHEM | Technology solutions
Disaggregation of Revenue [Line Items]
Total Revenues	$ 2,464	$ 4,145	$ 5,046	$ 8,511

Revenue - Disaggregated Revenue

Revenue - Disaggregated Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
United States
Disaggregation of Revenue [Line Items]
Total Revenues	3,310	7,562	6,407	16,377
Latin America
Disaggregation of Revenue [Line Items]
Total Revenues	59	17	205	192
Europe
Disaggregation of Revenue [Line Items]
Total Revenues	197	668	590	1,285
Asia
Disaggregation of Revenue [Line Items]
Total Revenues	835	701	977	1,249
Total Foreign Revenues
Disaggregation of Revenue [Line Items]
Total Revenues	$ 1,091	$ 1,386	$ 1,772	$ 2,726

Revenue - Timing of Revenue Rec

Revenue - Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
Products transferred at a point in time
Disaggregation of Revenue [Line Items]
Total Revenues	2,932	5,153	5,981	10,567
Products and services transferred over time
Disaggregation of Revenue [Line Items]
Total Revenues	$ 1,469	$ 3,795	$ 2,198	$ 8,536

Revenue - Remaining Performance

Revenue - Remaining Performance Obligations (Details) $ in Thousands	Jun. 30, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligations	$ 8,321
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligations	$ 4,845
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, period	1 year

Revenue - Components of Account

Revenue - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Trade receivables	$ 4,592	$ 6,425
Unbilled receivables	1,763	1,857
Other short-term receivables	19	7
Allowance for doubtful accounts	(716)	(1,816)
Total accounts receivable	$ 5,658	$ 6,473

Restructuring Activities - Char

Restructuring Activities - Charges and Net Assets (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Total Revenues	$ 4,401		$ 8,948		$ 8,179	$ 19,103
Net loss	(2,544)	$ (2,567)	(945)	$ (1,289)	(5,111)	(2,234)
Total assets	28,557				28,557		$ 32,224
Liabilities	7,427				7,427		6,049
Restructuring charge	0		30		0	625
CHINA
Restructuring Cost and Reserve [Line Items]
Remaining performance requirements for APC projects	29				29
Total Revenues	3		(28)		5	310
Net loss	(85)		(540)		42	(1,390)
Total assets	3,072				3,072		4,249
Liabilities	352				352		399
Total net assets	$ 2,720				$ 2,720		$ 3,850
CHINA | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charge			$ 30
CHINA | Facility Closing
Restructuring Cost and Reserve [Line Items]
Restructuring charge						$ 625

Restructuring Activities - Rese

Restructuring Activities - Reserve (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance	$ 0	$ 373	$ 0	$ 65
Amounts expensed	0	30	0	625
Amounts paid	0	(248)	0	(535)
Restructuring liability, ending balance	$ 0	$ 155	$ 0	$ 155

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	$ 23,453	$ 32,983	$ 26,175	$ 34,052
Balance at end of period	21,130	32,118	21,130	32,118
Foreign currency translation
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(2,009)	(1,181)	(1,778)	(1,285)
Total other comprehensive (loss) income	152	(43)	(79)	61
Total accumulated other comprehensive loss
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(2,009)	(1,181)	(1,778)	(1,285)
Balance at end of period	$ (1,857)	$ (1,224)	$ (1,857)	$ (1,224)

Treasury Stock (Details)

Treasury Stock (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Treasury stock (in shares)	808,139,000	796,090,000
Cost of common stock held in treasury	$ 1,618	$ 1,612

Earnings per Share - Basic Earn

Earnings per Share - Basic Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Basic weighted-average shares (in shares)	24,668,000	24,187,000	24,633,000	24,182,000
Conversion of unsecured loan notes (in shares)	0	0	0	0
Unexercised options and unvested RSUs (in shares)	0	0	0	0
Diluted weighted-average shares (in shares)	24,668,000	24,187,000	24,633,000	24,182,000

Earnings per Share - Narrative

Earnings per Share - Narrative (Details) - shares	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	553,000	1,515,000

Stock-Based Compensation -Addit

Stock-Based Compensation -Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	May 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 69,000	$ 123,000	$ 150,000	$ 219,000
Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares originally reserved (in shares)					5,600,676
Number of shares available for grant (in shares)	2,284,333		2,284,333
Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			10 years
Award service period (in years)			4 years
Unrecognized compensation costs	$ 0		$ 0
Incentive Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 208,000		$ 208,000
Unrecognized compensation cost, period of recognition (in years)			1 year 3 months 26 days
Incentive Plan | Restricted Stock Units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			2 years
Incentive Plan | Restricted Stock Units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of stock vested			$ 190,000
Incentive Plan | Second Anniversary of Award Date | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of options vesting	50.00%		50.00%
Incentive Plan | Third Anniversary of Award Date | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of options vesting	25.00%		25.00%
Incentive Plan | Fourth Anniversary of Award Date | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of options vesting	25.00%		25.00%
2019 Executive Performance RSU Award Agreement | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Required operating income			$ 1,000,000
Period before vesting begins			1 year
Deferred Plan | Deferred Compensation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 0	$ 0

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock options and restricted stock units, net of forfeited	$ 69	$ 123	$ 150	$ 219
Tax benefit of stock-based compensation expense	0	0	0	0
After-tax effect of stock-based compensation	$ 69	$ 123	$ 150	$ 219

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - Stock Options - Incentive Plan	6 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares
Number of Options
Outstanding, beginning of period (in shares) | shares	747,500
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Expired or forfeited (in shares) | shares	(40,000)
Outstanding, end of period (in shares) | shares	707,500
Number of Shares, exercisable (in shares) | shares	707,500
Weighted- Average Exercise Price
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 3.33
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	0
Expired or forfeited (in dollars per share) | $ / shares	5.50
Outstanding, end of period (in dollars per share) | $ / shares	3.21
Weighted average exercise price, exercisable (in dollars per share) | $ / shares	$ 3.21
Weighted- Average Remaining Contractual Term, Outstanding	4 years 5 months 23 days
Weighted- Average Remaining Contractual Term, Exercisable	4 years 5 months 23 days
Aggregate Intrinsic Value, Outstanding | $	$ 0
Aggregate Intrinsic Value, Exercisable | $	0
Unrecognized compensation costs | $	$ 0

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Incentive Plan - Restricted Stock	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Shares (in shares)
Beginning balance (in shares) | shares	775,635
Granted (in shares) | shares	0
Forfeited (in shares) | shares	(25,000)
Vested (in shares) | shares	(120,630)
Ending balance (in shares) | shares	630,005
Weighted Average Grant Date Fair Value (in Dollars per share)
Beginning balance (in dollars per share) | $ / shares	$ 1.47
Granted (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	0.97
Vested (in dollars per share) | $ / shares	1.57
Ending balance (in dollars per share) | $ / shares	$ 1.47

Debt Financing (Details)

Debt Financing (Details) - USD ($)	Apr. 17, 2020	Apr. 15, 2020	Jun. 19, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Line of Credit Facility [Line Items]
Proceeds from borrowings				$ 1,556,000	$ 0
Payment Protection Program Loan, CARES Act | U.S. Small Business Administration
Line of Credit Facility [Line Items]
Proceeds from borrowings	$ 1,556
Principal amount		$ 1,556
Interest rate		1.00%
Debt term		2 years
Cash Collateral Security Agreement | Standby Letters of Credit
Line of Credit Facility [Line Items]
Cash collateral, percentage of face amount of outstanding standby letters of credit			105.00%
Letters of credit, amount outstanding				2,860,000		$ 2,461,000
Restricted cash				$ 3,003,000		$ 2,584,000
Cash Collateral Security Agreement | Standby Letters of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate (as percent)			2.50%

Business Segment and Geograph_3

Business Segment and Geographic Financial Data (Details)	6 Months Ended
	Jun. 30, 2020segment
Segment Reporting [Abstract]
Number of reportable segments	2

Business Segment and Geograph_4

Business Segment and Geographic Financial Data - Reporting Segment Net Sales and Gross Margin (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenues from external customers	$ 4,401	$ 8,948	$ 8,179	$ 19,103
Cost of sales	(3,799)	(5,050)	(6,050)	(11,191)
Gross margin	602	3,898	2,129	7,912
Selling, general and administrative	(2,755)	(4,455)	(6,641)	(8,913)
Restructuring charge	0	(30)	0	(625)
Research and development	(271)	(205)	(595)	(471)
Intangible assets abandonment	0	(51)	0	(51)
Operating loss from continuing operations	(2,424)	(843)	(5,107)	(2,148)
Air Pollution Control Segment
Segment Reporting Information [Line Items]
Revenues from external customers	1,937	4,803	3,133	10,592
Cost of sales	(2,320)	(2,975)	(3,086)	(6,864)
Gross margin	(383)	1,828	47	3,728
Selling, general and administrative	0	0	0	0
Restructuring charge		(30)		(625)
Research and development	0	0	0	0
Intangible assets abandonment		0		0
Operating loss from continuing operations	(383)	1,798	47	3,103
FUEL CHEM Segment
Segment Reporting Information [Line Items]
Revenues from external customers	2,464	4,145	5,046	8,511
Cost of sales	(1,479)	(2,075)	(2,964)	(4,327)
Gross margin	985	2,070	2,082	4,184
Selling, general and administrative	0	0	0	0
Restructuring charge		0		0
Research and development	0	0	0	0
Intangible assets abandonment		0		0
Operating loss from continuing operations	985	2,070	2,082	4,184
Other
Segment Reporting Information [Line Items]
Revenues from external customers	0	0	0	0
Cost of sales	0	0	0	0
Gross margin	0	0	0	0
Selling, general and administrative	(2,755)	(4,455)	(6,641)	(8,913)
Restructuring charge		0		0
Research and development	(271)	(205)	(595)	(471)
Intangible assets abandonment		(51)		(51)
Operating loss from continuing operations	$ (3,026)	$ (4,711)	$ (7,236)	$ (9,435)

Business Segment and Geograph_5

Business Segment and Geographic Financial Data - Operations by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Revenues	$ 4,401	$ 8,948	$ 8,179	$ 19,103
United States
Revenues:
Revenues	3,310	7,562	6,407	16,377
Foreign
Revenues:
Revenues	$ 1,091	$ 1,386	$ 1,772	$ 2,726

Business Segment and Geograph_6

Business Segment and Geographic Financial Data - Assets by Geographic Area (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
ASSETS
Assets	$ 28,557	$ 32,224
United States
ASSETS
Assets	22,090	23,460
Foreign
ASSETS
Assets	$ 6,467	$ 8,764

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)lease_arrangement	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Number of lease arrangements | lease_arrangement			7
Operating lease cost	$ 79	$ 171	$ 167	$ 343
Short-term lease cost	4	0	7	68
Total lease cost	$ 83	$ 171	$ 174	$ 411
Weighted average remaining lease term	4 years 2 months 12 days		4 years 2 months 12 days
Weighted average discount rate	3.62%		3.62%
Minimum
Lessee, Lease, Description [Line Items]
Term of lease	11 months		11 months
Maximum
Lessee, Lease, Description [Line Items]
Term of lease	5 years		5 years

Leases - Lease Maturity (Detail

Leases - Lease Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
2020 (excluding the six months ended June 30, 2020)	$ 152
2021	303
2022	249
2023	242
Thereafter	206
Total lease payments	1,152
Less imputed interest	(135)
Total	$ 1,017	$ 980

Leases - Balance Sheet Classifi

Leases - Balance Sheet Classification (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease liabilities - current	$ 279	$ 300
Operating lease liabilities - non-current	738	680
Total operating lease liabilities	$ 1,017	$ 980

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 84	$ 172	$ 175	$ 343
Leased assets obtained in exchange for operating lease liabilities	$ 74	$ 165	$ 155	$ 328

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Contract liabilities (Note 3)	$ 1,168,000	$ 712,000
Accrued remediation contingency (Note 13)	0	146,000
Other accrued liabilities	936,000	1,118,000
Total other accrued liabilities	$ 2,104,000	$ 1,976,000

Contingencies (Details)

Contingencies (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Charge for non-conformance issue	$ 1,150
Reversal of allowance for doubt	499,000	$ 1,082,000	$ 0
Accrued remediation contingency	0	0		$ 146,000
Change in warranty liability balance		0	0
Warranty liability balance	$ 159,000	$ 159,000	$ 159,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate	0.00%	0.00%
Federal tax rate (as a percent)	21.00%
Unrecognized tax benefits	$ 0		$ 0

Goodwill and Other Intangibles

Goodwill and Other Intangibles (Details)	6 Months Ended
	Jun. 30, 2020USD ($)reporting_unit	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Goodwill [Line Items]
Number of reporting units | reporting_unit	2
Goodwill	$ 2,116,000		$ 2,116,000
Goodwill impairments	0	$ 0
Air Pollution Control Segment
Goodwill [Line Items]
Goodwill	0
FUEL CHEM Segment
Goodwill [Line Items]
Goodwill	$ 2,116,000		$ 2,116,000