ClearSign Technologies (CLIR) 10-K 12 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 12, 2019	Jun. 30, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	CLEARSIGN COMBUSTION CORP
Entity Central Index Key	0001434524
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 41,000,000
Trading Symbol	CLIR
Entity Common Stock, Shares Outstanding		26,697,261
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 8,949,000	$ 1,247,000
Short-term investments	6,923,000	0
Contract assets	39,000	184,000
Prepaid expenses and other assets	500,000	366,000
Total current assets	16,411,000	1,797,000
Fixed assets, net	457,000	498,000
Patents and other intangible assets, net	1,759,000	1,856,000
Other assets	10,000	10,000
Total Assets	18,637,000	4,161,000
Current Liabilities:
Accounts payable and accrued liabilities	1,080,000	768,000
Current portion of lease liabilities	216,000	159,000
Accrued compensation and taxes	341,000	607,000
Total current liabilities	1,637,000	1,534,000
Long Term Liabilities:
Long term lease liabilities	91,000	195,000
Total liabilities	1,728,000	1,729,000
Commitments and conttingencies
Stockholders' Equity:
Preferred stock, $0.0001 par value, zero shares issued and outstanding	0	0
Common stock, $0.0001 par value, 26,697,261 and 15,608,853 shares issued and outstanding at December 31, 2018 and December 31, 2017, respectively	3,000	2,000
Additional paid-in capital	76,417,000	52,441,000
Accumulated deficit	(59,511,000)	(50,011,000)
Total stockholders' equity	16,909,000	2,432,000
Total Liabilities and Stockholders' Equity	$ 18,637,000	$ 4,161,000

Consolidated Balance Sheets _Pa

Consolidated Balance Sheets [Parenthetical] - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares issued	26,697,261	15,608,853
Common stock, shares outstanding	26,697,261	15,608,853

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Sales	$ 530,000	$ 540,000
Cost of goods sold	427,000	380,000
Gross profit	103,000	160,000
Operating expenses:
Research and development	4,052,000	4,712,000
General and administrative	5,622,000	5,160,000
Total operating expenses	9,674,000	9,872,000
Loss from operations	(9,571,000)	(9,712,000)
Other income:
Interest income	71,000	32,000
Net loss	$ (9,500,000)	$ (9,680,000)
Net loss per share - basic and fully diluted	$ (0.42)	$ (0.63)
Weighted average number of shares outstanding - basic and fully diluted	22,856,210	15,421,095

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2016	$ 2,244,000	$ 1,000	$ 42,574,000	$ (40,331,000)
Balances (in shares) at Dec. 31, 2016		12,983,938
Shares issued in rights offering ($3.03 per share)	7,258,000	$ 1,000	7,257,000	0
Shares issued in rights offering ($3.03 per share) (in shares)		2,395,471
Warrants issued in rights offering ($0.97 per warrant)	2,324,000	$ 0	2,324,000	0
Issuance costs of rights offering	(915,000)	0	(915,000)	0
Shares issued in payment of accrued compensation ($3.60 per share)	490,000	$ 0	490,000	0
Shares issued in payment of accrued compensation ($3.60 per share) (in shares)		136,110
Shares issued for services ($4.85 per share)	24,000	$ 0	24,000	0
Shares issued for services ($4.85 per share) (in shares)		5,000
Shares issued for services ($3.50 per share)	18,000		18,000
Shares issued for services ($3.50 per share) (in shares)		5,000
Shares issued for 2017 board services ($3.60 per share)	300,000	$ 0	300,000	0
Shares issued for 2017 board services ($3.60 per share) (In shares)		83,334
Share Based Compensation	369,000	$ 0	369,000	0
Net loss	(9,680,000)	0	0	(9,680,000)
Balances at Dec. 31, 2017	2,432,000	$ 2,000	52,441,000	(50,011,000)
Balances (in shares) at Dec. 31, 2017		15,608,853
Shares issued in stock offerings ($2.25 per share)	24,668,000	$ 1,000	24,667,000	0
Shares issued in stock offerings ($2.25 per share) (in shares)		10,963,543
Issuance costs of rights offering	(1,157,000)	$ 0	(1,157,000)	0
Shares issued for services ($3.50 per share)	26,000	$ 0	26,000	0
Shares issued for services ($3.50 per share) (in shares)		7,500
Shares issued for services ($1.44 per share)	4,000	$ 0	4,000	0
Shares issued for services ($1.44 per share) (in shares)		2,500
Shares issued for 2018 board service ($1.85 per share)	212,000	$ 0	212,000	0
Shares issued for 2018 board service ($1.85 per share) (in shares)		114,865
Share Based Compensation	224,000	$ 0	224,000	0
Net loss	(9,500,000)	0	0	(9,500,000)
Balances at Dec. 31, 2018	$ 16,909,000	$ 3,000	$ 76,417,000	$ (59,511,000)
Balances (in shares) at Dec. 31, 2018		26,697,261

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity [Parenthetical] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Common stock for services per share issue one	$ 3.50	$ 4.85
Common stock for services per share issue two	1.44	3.50
Stock Issued During Period Rights Offering Per Share	2.25	3.03
Warrants Issued During Period Rights Offering Per Share		0.97
Stock Issued During Period In Payment Of Accrued Compensation Per Share		3.60
Stock Issued During Period 2017 Board Services Per Share		$ 3.60
Stock Issued During Period Board Services Per Share	$ 1.85

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (9,500,000)	$ (9,680,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Common stock issued for services	242,000	342,000
Share based compensation	224,000	369,000
Depreciation and amortization	271,000	297,000
Abandonment and impairment of capitalized patent costs	322,000	0
Change in operating assets and liabilities:
Contract assets	145,000	(184,000)
Accounts receivable	0	103,000
Prepaid expenses and other assets	(134,000)	169,000
Accounts payable and accrued liabilities	312,000	13,000
Accrued compensation and taxes	(266,000)	428,000
Contract liabilities	0	(115,000)
Net cash used in operating activities	(8,384,000)	(8,258,000)
Cash flows from investing activities:
Acquisition of fixed assets	(94,000)	(94,000)
Disbursements for patents and other intangible assets	(408,000)	(327,000)
Investment in short-term treasury bills	(6,923,000)	0
Net cash used in investing activities	(7,425,000)	(421,000)
Cash flows from financing activities:
Proceeds from issuance of common stock and units of common stock and warrants for cash, net of offering costs	23,511,000	8,667,000
Net cash provided by financing activities	23,511,000	8,667,000
Net increase (decrease) in cash and cash equivalents	7,702,000	(12,000)
Cash and cash equivalents, beginning of year	1,247,000	1,259,000
Cash and cash equivalents, end of year	$ 8,949,000	$ 1,247,000

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows [Parenthetical] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash Flow Noncash Operating Activities Disclosure [Abstract]
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	136,110
Due to Officers or Stockholders, Current		$ 490,000

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Note 1 – Organization and Description of Business ClearSign Combustion Corporation (ClearSign or the Company) designs and develops technologies for the purpose of improving key performance characteristics of combustion systems, including emission and operational performance, energy efficiency and overall cost-effectiveness. The Company’s primary technologies include its Duplex technology, which achieves very low emissions without the need of external flue gas recirculation, selective catalytic reduction, or higher excess air operation, and its Electrodynamic Combustion Control or ECC technology, which introduces a computer-controlled electric field into the combustion region that may better control gas-phase chemical reactions and improve system performance and cost-effectiveness. The Company is headquartered in Seattle, Washington and was incorporated in the state of Washington in 2008. On July 28, 2017, the Company incorporated a subsidiary, ClearSign Asia Limited, in Hong Kong to represent the Company’s business and technological interests throughout Asia. Through ClearSign Asia Limited, the Company has established a Wholly Foreign Owned Enterprise (WFOE) in China – ClearSign Combustion (Beijing) Environmental Technologies Co., LTD. Unless otherwise stated or the context otherwise requires, the terms ClearSign and the “Company” refers to ClearSign Combustion Corporation and its wholly-owned subsidiary, ClearSign Asia Limited. Liquidity The Company’s technologies are currently in field development and have generated nominal revenues from operations to date to meet operating expenses. In order to generate meaningful revenues, the technologies must be fully developed, gain market recognition and acceptance, and develop a critical level of successful sales and product installations. The Company has historically financed its operations primarily through issuances of equity securities, including $11.9 million in proceeds, net of offering costs, from a stock offering completed on February 27, 2018 and $11.6 million in proceeds, net of offering costs, from a stock offering completed on July 20, 2018. The Company has incurred losses since its inception totaling $59,511,000 and expects to experience operating losses and negative cash flows for the foreseeable future. Management believes that the successful growth and operation of the Company’s business is dependent upon its ability to obtain adequate sources of funding through co-development agreements, strategic partnering agreements, or equity or debt financing to adequately support research and development efforts, protect intellectual property, form relationships with strategic partners, and provide for working capital and general corporate purposes. There can be no assurance that the Company will be successful in achieving its long-term plans as set forth above, or that such plans, if consummated, will result in profitable operations or enable the Company to continue in the long-term as a going concern.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Note 2 – Summary of Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of ClearSign and its subsidiary. Intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Revenue Recognition and Cost of Sales The Company recognizes revenue and related cost of goods sold in accordance with FASB ASC 606 Revenue from Contracts with Customers (ASC 606). Revenues and cost of goods sold are recognized once the goods or services are delivered to the customer’s control and performance obligations are satisfied. Typically, the Company’s contracts with customers have performance obligations regarding air emissions and operational performance that are satisfied upon completion of service. Since this is the singular performance obligation and cannot be achieved until the air emissions and operational performance have been successfully tested, revenue related to the contracts is recognized upon project completion. The Company’s contracts generally include progress payments from the customer upon completion of defined milestones. As these payments are received they are offset against accumulated project costs and recorded as either contract assets or contract liabilities. Upon completion of the performance obligations and acceptance by the customer the projects can be recorded as revenue. The Company's contracts with customers contain no variable considerations or incentives or discounts that would cause revenue to be allocated or adjusted over time. Therefore, no separate methods of evaluating the contracts other than consideration of the price at achievement of the performance objectives was used in satisfying the review requirements of ASC 606. Contract acquisition costs and practical expedients For contracts that have a duration of less than one year, the Company follows ASC 606, practical expedients and expenses those costs when incurred; for contracts with a life exceeding one year, the Company records those costs when performance obligations related to the contract are completed. The Company generally expenses sales commissions when earned. The Company records those costs within general and administrative expenses. Product Warranties The Company warrants all installed products against defects in materials and workmanship for a period specified in each contract by replacing failed parts. Accruals for product warranties are based on historical warranty experience and current product performance trends, and are recorded at the time revenue is recognized as a component of cost of sales. The warranty liabilities are reduced by material and labor costs used to replace parts over the warranty period in the periods in which the costs are incurred. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary, and such adjustments could be material in the future if estimates differ significantly from actual warranty expense. The warranty liabilities are included in accrued liabilities in the balance sheets. Cash and Cash Equivalents Highly liquid investments purchased with an original maturity of three months or less are considered cash equivalents. Cash is maintained with a commercial bank where accounts are generally guaranteed by the Federal Deposit Insurance Corporation up to $250,000. The Company’s deposits may at times exceed this limit. The Company also maintains a cash balance in China. Accounts at such banks are insured up to $75,000 (500,000RMB). The Company has not experienced losses in such accounts and believes it is not exposed to any significant credit risk on cash and cash equivalents. Short-Term Investments Short-term investments consist of U.S. Treasury bills with original maturities of twelve months or less and greater than three months. These short-term investments are classified as held to maturity and are recorded on an amortized cost basis which approximates fair value. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount. An allowance for doubtful accounts is established, as necessary, based on past experience and other factors which, in management’s judgment, deserve current recognition in estimating bad debts. The determination of the collectability of amounts due from customer accounts requires the Company to make judgments regarding future events and trends. Allowances for doubtful accounts are determined based on assessing the Company’s portfolio on an individual customer and on an overall basis. This process consists of a review of historical collection experience, current aging status of the customer accounts, and the financial condition of the Company’s customers. Based on a review of these factors, the Company may establish or adjust the allowance for specific customers and the accounts receivable portfolio as a whole. Fixed Assets and Leases Fixed assets are recorded at cost. Leases are recorded in accordance with FASB ASC 842 Leases . For those leases with a term greater than one year, the Company recognizes on the balance sheet at the time of lease inception or modification a right-of-use asset and a lease liability, initially measured at the present value of the lease payments. Lease costs are recognized in the income statement over the lease term on a straight-line basis. Operating leases with a term of 1 year or less are recognized on a straight line basis over the term. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are depreciated over the life of the lease or their useful life, whichever is shorter. All other fixed assets are depreciated over two to four years. Maintenance and repairs are expensed as incurred. Patents and Trademarks Patents and trademarks are recorded at cost. Amortization is computed using the straight-line method over the estimated useful lives of the assets once they are awarded. Impairment of Long-Lived Assets The Company tests long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable through the estimated undiscounted cash flows expected to result from the use and eventual disposition of the assets. In that event, a loss is recognized based on the amount by which the carrying amount exceeds the fair value of the long-lived assets. Fair value is determined based on the present value of estimated expected cash flows using a discount rate commensurate with the risks involved, quoted market prices, or appraised values depending upon the nature of the assets. Loss on long-lived assets to be disposed of is determined in a similar manner, except that fair values are reduced for the cost of disposal. Fair Value of Financial Instruments Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities measured at fair value are categorized based on whether or not the inputs are observable in the market and the degree that the inputs are observable. The categorization of financial assets and liabilities within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels of inputs used to establish fair value are the following:  Level 1 – Quoted prices in active markets for identical assets or liabilities;  Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and  Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company's financial instruments primarily consist of cash and cash equivalents, short-term investments, accounts payable and accrued expenses. As of the balance sheet dates, the estimated fair values of the financial instruments were not materially different from their carrying values as presented on the balance sheets. This is primarily attributable to the short-term maturities of these instruments. The Company did not identify any other non-recurring assets and liabilities that are required to be presented in the balance sheets at fair value. Research and Development The cost of research and development is expensed as incurred. Research and development costs consist of salaries, benefits, share based compensation, consulting fees, rent, utilities, depreciation, and consumables. In 2018, the Company received $44,000 to partially fund specific research and development activity relating to its ECC technology. Since these funds were provided without expectation of reciprocation, except notification of research results, the funds received were offset against the related research and development costs incurred. Income Taxes The Company accounts for income taxes using an asset and liability approach which allows for the recognition and measurement of deferred tax assets based upon the likelihood of realization of tax benefits in future years. Under the asset and liability approach, deferred taxes are provided for the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. A valuation allowance is provided for deferred tax assets if it is more likely than not these items will either expire before the Company is able to realize their benefits, or that future deductibility is uncertain. Tax benefits from an uncertain tax position are recognized only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate resolution. Stock-Based Compensation The costs of all employee stock options, as well as other equity-based compensation arrangements, are reflected in the consolidated financial statements based on the estimated fair value of the awards on the grant date. That cost is recognized over the period during which an employee is required to provide service in exchange for the award. Stock compensation for stock granted to non-employees is determined as the fair value of the consideration received or the fair value of equity instruments issued, whichever is more reliably measured. Foreign Operations The accompanying consolidated financial statements as of December 31, 2018 and 2017 include assets amounting to approximately $199,000 and $0, respectively, relating to operations of the Company in China. It is always possible unanticipated events in foreign countries could disrupt the Company’s operations. Foreign Currency The functional currency of ClearSign Asia Limited is the U.S. dollar. The Company remeasures the transactions denominated in Chinese Yuan at the average exchange rate in effect during the period. At the end of each reporting period, the Company remeasures ClearSign Asia Limited’s monetary assets and liabilities to the U.S. dollar using exchange rates in effect at the end of the reporting period. The Company remeasures its non-monetary assets and liabilities at historical exchange rates. The Company records gains and losses related to remeasurement in other income (expense), net in the consolidated statements of operations. Foreign currency exchange gain (losses) has not been significant in any period presented and the Company has not undertaken any hedging transactions related to foreign currency exposure. Net Loss per Common Share Basic loss per share is computed by dividing loss available to common stockholders by the weighted-average number of common shares outstanding. Diluted loss per share is computed similar to basic loss per share except that the denominator is increased to include additional common shares available upon exercise of stock options and warrants using the treasury stock method, except for periods for which no common share equivalents are included because their effect would be anti-dilutive. At December 31, 2018 and 2017, potentially dilutive shares outstanding amounted to 3,376,061 and 3,489,644, respectively. Recently Adopted Standards In May 2017 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2017-09 Scope of Modification Accounting, clarifies Topic 718, Compensation – Stock Compensation , which requires a company to apply modification accounting to changes in the terms or conditions of a share-based payment award unless all of the (1) the fair value of the modified award is the same as the fair value of the original award immediately before the modification. The ASU indicates that if the modification does not affect any of the inputs to the valuation technique used to value the award, the entity is not required to estimate the value immediately before and after the modification; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the modification; and (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the modification. The ASU is effective for all entities for fiscal years beginning after December 15, 2017, including interim periods within those years. The Company currently does not have any modifications to existing stock compensation agreements and will be able to calculate the impact of the ASU once modifications arise. Recently Issued Accounting Pronouncements In June 2018 FASB issued ASU No. 2018-07 Compensation-Stock Compensation. In November 2018 FASB issued ASU 2018-18 Topic 808 Collaborative Arrangements, Management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s consolidated financial statement presentation or disclosures.

Fixed Assets

Fixed Assets	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	Note 3 – Fixed Assets Fixed assets are summarized as follows: December 31, 2018 2017 Machinery and equipment $ 853,000 $ 801,000 Office furniture and equipment 186,000 167,000 Leasehold improvements 150,000 147,000 Right of use asset-operating leases 637,000 518,000 Accumulated depreciation and amortization (1,369,000 ) (1,135,000 ) $ 457,000 $ 498,000 The Company has a triple net operating lease for office and laboratory space in Seattle, Washington through March 2020 with rent of approximately $12,000 per month plus triple net operating costs. The Company also has a triple net operating lease for office space in Tulsa, Oklahoma through August 2019 with monthly rent of approximately $2,000 per month plus triple net operating costs. Both leases include lessee renewal options for three years at the then prevailing market rate. The Company has an operating lease for office space in Beijing, China through November 2020 with a monthly rent of $6,000. Lease costs for the years ended December 31, 2018 and 2017 and other quantitative disclosures are as follows: For the years ended December 31, 2018 2017 Lease cost: Operating lease cost $ 218,000 $ 214,000 Short-term lease cost - 47,000 Total lease cost $ 218,000 $ 261,000 Other information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 181,000 Right-of-use assets obtained in exchange for new operating lease liabilities For operating lease: Weighted average remaining lease term (in years) 1.47 Weighted average discount rate 5.56 % Minimum future payments under the Company’s leases at December 31, 2018 and their application to the corresponding lease liabilities are as follows: Discounted ‎ lease ‎liability ‎payments Payments ‎ due under ‎lease ‎agreements 2019 216,000 221,000 2020 91,000 92,000 Total $ 307,000 $ 313,000

Patents and Other Intangible As

Patents and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	Note 4 – Patents and Other Intangible Assets Patents and other intangible assets are summarized as follows: December 31, 2018 2017 Patents Patents pending $ 1,202,000 $ 1,167,000 Issued patents 761,000 930,000 1,963,000 2,097,000 Trademarks Trademarks pending 55,000 41,000 Registered trademarks 23,000 23,000 78,000 64,000 Other 8,000 8,000 2,049,000 2,169,000 Accumulated amortization (290,000 ) (313,000 ) $ 1,759,000 $ 1,856,000 Future amortization expense associated with awarded patents and registered trademarks as of December 31, 2018 is estimated as follows: 2019 $ 169,000 2020 142,000 2021 88,000 2022 62,000 2023 32,000 Thereafter 7,000 $ 500,000 In 2018, the Company reassessed its patent portfolio in order to ensure that both the cost-effectiveness and the value created through the intellectual property portfolio were maximized and to focus resources on its most promising patents. Those patents considered to be the most beneficial were retained and those pending patents projected to be unnecessarily costly that could be disposed of without meaningfully degrading the quality of the remaining intellectual property portfolio were abandoned. As a result, during the year ended December 31, 2018, the Company recorded impairment loss of $322,000 of capitalized patents costs. There was no such impairment loss recognized during the year ended December 31, 2017.

Sales, Contract Assets and Cont

Sales, Contract Assets and Contract Liabilities	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Note 5 – Sales, Contract Assets and Contract Liabilities During 2018, the Company recognized revenue totaling $ 360,000 128,000 42,000 $39,000 and contract liabilities of $0.

Product Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2018
Product Warranties Disclosures [Abstract]
Product Warranty Disclosure [Text Block]	Note 6 – Product Warranties A summary of the Company’s warranty liability activity, which is included in accrued liabilities in the accompanying balance sheets as of December 31, 2018 and 2017, is as follows: 2018 2017 Warranty liability, beginning of year $ 181,000 $ 213,000 Accruals 51,000 69,000 Payments (32,000 ) (114,000 ) Adjustments and other 57,000 13,000 Warranty liability, end of year $ 257,000 $ 181,000

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Note 7 - Income Taxes Through December 31, 2018, the Company incurred net operating losses for federal tax purposes of approximately $55,000,000. The net operating loss carry forwards may be used to reduce taxable income through the years 2028 to 2038. The availability of the Company's net operating loss carry forwards is subject to limitation if there is a change in the ownership of the Company's stock of 50% or more. A reconciliation of the expected tax computed at the statutory federal income tax rate to the provision for income taxes is as follows: 2018 2017 Expected tax benefit at 21% $ (1,970,000 ) $ (3,291,000 ) Tax Reform 6,210,000 Change in valuation allowance 1,890,000 (3,070,000 ) Other 80,000 151,000 Provision for income taxes $ - $ - The net deferred tax asset at December 31, 2018 and 2017 was $11,910,000 and $10,020,000, respectively. In assessing the potential realization of these deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the Company attaining future taxable income during the periods in which those temporary differences become deductible. At December 31, 2018 and 2017, management was unable to determine if it is more likely than not that the Company’s deferred tax assets will be realized and has therefore recorded an appropriate valuation allowance against deferred tax assets at such dates. Significant components of the deferred tax assets (liabilities), are approximately as follows: 2018 2017 Net operating loss carry forwards $ 11,540,000 $ 9,860,000 Accrued liabilities 280,000 210,000 Stock compensation (50,000 ) (90,000 ) Depreciation 160,000 60,000 Prepaid expenses (20,000 ) (20,000 ) Other - - Deferred tax assets, net 11,910,000 10,020,000 Valuation allowance (11,910,000 ) (10,020,000 ) Net deferred tax asset $ - $ - Although the Company is not under examination, the tax years for 2015 and forward are subject to examination by United States tax authorities. The Company’s practice is to recognize interest and penalties related to income tax matters in income tax expense. As of December 31, 2018, and 2017, there were no accrued interest or penalties related to uncertain tax positions. On December 22. 2017. The Tax Cuts and Jobs Act (the “Tax Act”) was signed into law. The Tax Act contains significant changes to corporate taxation, including (i) the reduction of the corporate income tax rate to 21%, (ii) the acceleration of expensing for certain business assets, (iii) the one-time transition tax related to the transition of U.S. international tax from a worldwide tax system to a territorial tax system, (iv) the repeal of the domestic production deduction, (v) additional limitations on the deductibility of interest expense and (vi) expanded limitations on executive compensation. The key impact of the Tax Act on the Company’s financial statements for the year ended December 31, 2017 was the re-measurement of deferred tax balances to the new corporate tax rate. In order to calculate the effects of the new corporate tax rate on the Company’s deferred tax balances, ASC 740 “Income Taxes” (“ASC 740’) required the re-measurement of the Company’s deferred tax balances as of the enactment date of the Tax Act, based on the rates at which the balances are expected to reverse in the future. The re-measurement of the Company’s deferred tax balances resulted in a net reduction in deferred tax assets of $6.2 million offset with a corresponding adjustment to the valuation allowance.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Note 8 – Stockholders’ Equity Common Stock and Preferred Stock The Company is authorized to issue 62,500,000 shares of common stock and 2,000,000 shares of preferred stock. Preferences, limitations, voting powers and relative rights of any preferred stock to be issued may be determined by the Company’s Board of Directors. The Company has not issued any shares of preferred stock. In February 2018, the Company completed an offering of common stock whereby 5,750,000 shares of common stock at a price of $2.25 per share were issued and sold for net cash proceeds of approximately $11.9 million. In July 2018, the Company completed a private equity offering of 5,213,543 shares of common stock at a price of $2.25 per share to ClirSPV, LLC (Investor). Gross proceeds from the offering totaled $11.7 million and net cash proceeds approximated $11.6 million. The Stock Purchase Agreement permitted the Investor to purchase from the Company up to an aggregate 478,854 shares of common stock at a price of $4 The Stock Purchase Agreement also permits the Investor to participate in future capital raising transactions (Participation Right) on the same terms as other investors participating in such transactions. The Participation Right will expire on December 31, 2023. In no event may the Participation Right be exercised to the extent it would cause the Investor or any of its affiliates to beneficially own 20% or more of the Company’s then outstanding common stock or hold shares with 20% or more of the voting power. The Company filed a registration statement to register the shares issued in this private offering and shares underlying the Additional Purchase Right. The registration statement was declared effective by the SEC on September 21, 2018. In January 2017, the Company completed a rights offering and public offering of units comprised of common stock and warrants at a purchase price of $4.00 per unit pursuant to which the Company issued 2,395,471 shares of common stock together with warrants for the purchase of 2,395,471 shares of common stock. The warrants allowed each holder to purchase one share of common stock at an exercise price of $4.00 per share, were non-callable, and were publicly traded on the Nasdaq Capital Market under the symbol “CLIRW” until they expired on January 25, 2019. Gross proceeds from the offering totaled $9.6 million and net cash proceeds approximated $8.7 million. Expenses of the offering approximated $915,000, including dealer-manager and placement agent fees of $575,000 paid to MDB Capital Group LLC (MDB) and MDB’s legal fees of $60,000. The net cash proceeds were allocated to the relative fair values of the common stock and warrants on the date of issuance resulting in an allocation of $3.03 per share to the common stock and $0.97 per share to the warrants. Equity Incentive Plan The ClearSign Combustion Corporation 2011 Equity Incentive Plan (the Plan) provides for the granting of options to purchase shares of common stock, stock awards to purchase shares at no less than 85% of the value of the shares, and stock bonuses to officers, employees, board members, certain consultants, and advisors. The Compensation Committee of the Board of Directors is authorized to administer the Plan and establish the grant terms, including the grant price, vesting period and exercise date. As of December 31, 2018, the number of shares reserved for issuance under the Plan totaled 2,768,618 shares. The Plan provides for quarterly increases in the available number of authorized shares equal to the lesser of 10% of any new shares issued by the Company during the quarter immediately prior to the adjustment date or such lesser amount as the Board of Directors shall determine. Activity under the Plan is as follows: 2018 2017 Reserved but unissued shares under the Plan, beginning of year 191,656 266,884 Increases in the number of authorized shares under the Plan 1,106,088 255,261 Grants of stock options (224,000 ) (127,000 ) Stock option forfeitures 337,583 15,955 Exercise of stock options - - Stock grants (114,865 ) (219,444 ) Stock grant forfeitures - - Reserved but unissued shares under the Plan, end of year 1,296,462 191,656 Stock Options In 2018, the Company granted from the Plan to certain employees stock options for the purchase of 224,000 shares of stock. The stock options have exercise prices based on the grant date fair values ranging from $1.85 to $2.10 per share with a weighted average of $1.94 per share, a contractual life of 10 years, and vesting over three to four years. As permitted by SAB 107, due to the Company’s insufficient history of option activity, management utilized the simplified approach to estimate the expected term of the options, which represents the period of time that options granted are expected to be outstanding. Expected volatility was determined through the Company’s historical stock price volatility. The Company estimated the forfeiture rate at the time of grant and will revise it, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company recognizes compensation costs only for those equity awards expected to vest. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield in effect at the time of grant. The Company has never declared or paid dividends and has no plans to do so in the foreseeable future. The following weighted-average assumptions were utilized in the calculation of the fair value of the stock options: Expected life 6.20 years Weighted average volatility 70 % Forfeiture rate 15 % Weighted average risk-free interest rate 2.74 % Expected dividend rate 0 % The fair value of stock options granted, estimated on the date of grant using the Black-Scholes option valuation model, was $236,000. The recognized compensation expense associated with these grants in 2018 was $43,000. On December 31, 2018 the Company entered into a consulting agreement with its former Chief Executive Officer, Stephen Pirnat, which expires on December 31, 2020. Pursuant to the terms of the consulting agreement, Mr. Pirnat’s vested options were extended for a period of two years. The compensation expense associated with the extension of the term of the fully vested options was immaterial. A summary of the Company’s stock option activity and related information is as follows: 2018 2017 Options to ‎ Purchase ‎ Common ‎ Stock Weighted ‎ Average ‎ Exercise ‎ Price Weighted ‎ Average ‎ Remaining ‎ Contractual ‎ Life (in ‎ years) Options to ‎ Purchase ‎ Common ‎ Stock Weighted ‎ Average ‎ Exercise ‎ Price Weighted ‎ Average ‎ Remaining ‎ Contractual ‎ Life (in ‎ years) Outstanding at January 1 993,860 $ 4.81 6.94 882,815 $ 4.98 7.51 Granted 224,000 $ 1.94 9.23 127,000 $ 3.69 9.48 Exercised - - - - - - Forfeited/Expired/Exchanged (337,583 ) $ 4.19 - (15,955 ) $ 5.15 - Outstanding at December 31 880,277 $ 4.32 9.04 993,860 $ 4.81 6.94 Exercisable at December 31 587,962 $ 5.17 6.49 754,989 $ 4.98 6.32 A summary of the status of the Company’s non-vested stock options at December 31 and changes during the year is as follows: 2018 2017 Number of ‎ Options Weighted ‎ Average ‎ Date Number of ‎ Options Weighted ‎ Average ‎ Date Non-vested stock options at January 1 238,871 $ 4.27 335,283 $ 5.09 Granted 224,000 $ 1.94 127,000 $ 3.74 Vested (122,647 ) $ 4.15 (207,457 ) $ 5.16 Exercised - - - - Forfeited/Expired/Exchanged (47,909 ) $ 3.82 (15,955 ) $ 5.15 Non-vested stock options at December 31 292,315 $ 2.61 238,871 $ 4.27 The estimated aggregate pretax intrinsic value of the Company’s outstanding vested stock options at December 31, 2018 is $0. The intrinsic value is the difference between the Company’s common stock price and the option exercise prices multiplied by the number of in-the-money options. This amount changes based on the fair value of the Company’s common stock. At December 31, 2018, there was $377,000 of total unrecognized compensation cost related to non-vested stock option-based compensation arrangements granted under the Plan. That cost is expected to be recognized in future years as follows: 2019 184,000 2020 119,000 2021 63,000 2022 11,000 $ 377,000 The recognized compensation cost associated with the Plan is as follows: 2018 2017 Research and development $ 145,000 $ 119,000 General and administrative 79,000 250,000 Effect on net loss $ 224,000 $ 369,000 Effect on net loss per share $ 0.01 $ 0.02 Stock Grants In May 2018, the Company authorized shares of common stock to be issued under the Plan to its non-executive directors in accordance with board agreements. The shares were earned quarterly for service in 2018. The Company recognized $212,000, represented by 114,865 shares, in general and administrative expense through December 31, 2018. In February 2017, the Company granted 136,110 shares of common stock under the Plan to its six officers as payment for bonuses that were accrued at December 31, 2016. The per share fair value of the stock at the time of grant was $3.60 for a total value of $490,000 which the Company had recognized as bonuses in 2016. The common stock was subject to repurchase rights by the Company at $0.0001 per share through February 10, 2018. In 2017, the Company issued 83,334 shares of common stock under the Plan to its three non-executive directors for 2018 compensation in accordance with agreements entered into with each director. The common stock was subject to repurchase rights by the Company at $0.0001 per share through February 10, 2018 upon the termination of the individual’s services as a director or other circumstances as set forth in the award agreements. The fair value of the stock at the time of grant was $3.60 per share for a total value of $300,000, which the Company recognized in general and administrative expense in 2017. Consultant Stock Plan The 2013 Consultant Stock Plan (the Consultant Plan) provides for the granting of shares of common stock to consultants who provide services related to capital raising, investor relations, and making a market in or promoting the Company’s securities. The Company’s officers, employees, and board members are not entitled to receive grants from the Consultant Plan. The Compensation Committee of the Board of Directors is authorized to administer the Consultant Plan and establish the grant terms. The number of shares reserved for issuance under the Consultant Plan on December 31, 2018 totaled 199,705 shares. The Consultant Plan provides for quarterly increases in the available number of authorized shares equal to the lesser of 1% of any new shares issued by the Company during the quarter immediately prior to the adjustment date or such lesser amount as the Board of Directors shall determine. The Company granted 7,500 and 10,000 $3.50 $26,000 and $35,000 $30,000 and $42,000, respectively. Activity under the Consultant Plan is as follows: 2018 2017 Reserved but unissued shares under the Consultant Plan at January 1 99,159 83,633 Increases in the number of authorized shares under the Consultant Plan 110,546 25,526 Stock grants (10,000 ) (10,000 ) Reserved but unissued shares under the Consultant Plan at Period End 199,705 99,159 Warrants In conjunction with the January 2017 rights offering, the Company issued warrants for the purchase of 2,395,471 shares of common stock at $4.00 per share. The warrants expired on January 25, 2019. A summary of the Company’s warrant activity and related information is as follows: 2018 2017 Warrants Weighted ‎ Average ‎ Exercise ‎ Price Warrants Weighted ‎ Average ‎ Exercise ‎ Price Outstanding at January 1 2,495,784 $ 3.98 445,313 $ 4.65 Granted - - 2,395,471 $ 4.00 Exercised - - - - Forfeited/Expired - - (345,000 ) $ 5.00 Outstanding at Period End 2,495,784 $ 3.98 2,495,784 $ 3.98 The following table summarizes the number of warrants, the weighted average exercise price, and weighted average life (in years) by price for both total outstanding warrants and total exercisable warrants at December 31, 2018: Total Outstanding Warrants Exercise Price Warrants Wtd. Avg. ‎ Exercise ‎ Price Remaining ‎ Life ‎ (in years) $1.80 80,000 $ 1.80 2.13 $4.00 2,395,471 $ 4.00 0.07 $10.00 20,313 $ 10.00 0.18 2,495,784 $ 3.98 The intrinsic value of the outstanding warrants was $0 at December 31, 2018.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2018
Retirement Plan [Abstract]
Retirement Plan [Text Block]	Note 9 – Retirement Plan The Company has a defined contribution retirement plan covering all of its employees whereby the Company matches employee contributions up to 3% of each employee’s 2018 and 2017 earnings. The Company’s matching contribution expense totaled $85,000 and $86,000 in 2018 and 2017, respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Note 10 – Related Party Transactions In connection with the January 2017 rights offering, the Company paid the dealer-manager and placement agent, MDB Capital Group LLC, fees of $575,000 and legal fees and other costs of $60,000. MDB and its chief executive officer were significant owners of the Company’s common stock at the time of this offering. In November 2018, one of the Company’s shareholders, who is also a co-founder and member of MDB Capital Group LLC, filed a draft solicitation statement with the SEC seeking the support of the Company’s shareholders in making a demand that the Company call a special meeting of its shareholders. In January 2019, the Company entered into a Cooperation Agreement with this shareholder pursuant to which the shareholder withdrew his request to hold a special meeting. The Cooperation Agreement among other things, includes certain standstill provisions. The term of the Cooperation agreement will continue until the earlier of (i) the day immediately following the date of 2020 annual meeting or (ii) December 31, 2020. Pursuant to the terms of the Cooperation Agreement the Company reimbursed the shareholder $40,000 for expenses, which is included in accounts payable and accrued liabilities at December 31, 2018. Total costs incurred in connection with this matter, including the amount reimbursed to the shareholder, totaled approximately $364,000 and is included in general and administrative expenses for the year ended December 31, 2018.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Note 11 – Commitments and Contingencies Employment Contract On January 28, 2019, the Company entered into an employment contract with its President Dr. Colin ‘Jim’ Deller as described in Note 13. Litigation From time to time the Company may become involved in various lawsuits and legal proceedings which arise in the ordinary course of business. Litigation is subject to inherent uncertainties and an adverse result in any such matter may harm the Company’s business. As of the date of this report, we are not a party to any material pending legal proceedings.

Quarterly Results

Quarterly Results	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Note 12 – Quarterly Results (unaudited) Quarterly results for the years ended December 31, 2018 and 2017 are as follows: First Second Third Fourth Quarter Quarter Quarter Quarter For the year ended December 31, 2018 Revenue $ 530,000 $ - $ - $ - Gross Profit (Loss) $ 135,000 $ (20,000 ) $ (9,000 ) $ (3,000 ) Operating Expense $ 2,413,000 $ 2,370,000 $ 2,306,000 $ 2,585,000 Net Loss $ (2,278,000 ) $ (2,389,000 ) $ (2,292,000 ) $ (2,541,000 ) Net Loss per share - basic and fully diluted $ (0.13 ) $ (0.11 ) $ (0.09 ) $ (0.10 ) For the year ended December 31, 2017 Revenue $ 360,000 $ - $ - $ 180,000 Gross Profit (Loss) $ 109,000 $ - $ (15,000 ) $ 66,000 Operating Expense $ 2,502,000 $ 2,251,000 $ 2,460,000 $ 2,659,000 Net Loss $ (2,379,000 ) $ (2,236,000 ) $ (2,472,000 ) $ (2,593,000 ) Net Loss per share - basic and fully diluted $ (0.16 ) $ (0.17 ) $ (0.16 ) $ (0.17 )

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Note 13 – Subsequent Event On January 28, 2019 (the “Effective Date”), the Company and Colin James Deller entered into an employment agreement (the “Agreement”) pursuant to which the Company will employ Dr. Deller as its President until April 1, 2019, at which time Dr. Deller will become the Company’s Chief Executive Officer. Pursuant to the Agreement, the Company will pay Dr. Deller an annual salary of $350,000. As an inducement to accept employment with the Company, Dr. Deller was also granted an option to purchase 400,000 shares of the Company’s common stock at an exercise price of $1.16 per share and an option to purchase 200,000 shares of the Company’s common stock at an exercise price of $2.25 per share. Each option has a term of 10 years and will vest as follows: the right to purchase one-third of the shares of common stock subject to the option vested on the Effective Date; the right to purchase one-third of the shares will vest on the first anniversary of the grant date; and the right to purchase one-third of the shares will vest on the second anniversary of the grant date. The Company has agreed to pay certain expenses, not to exceed the sum of $100,000, related to Dr. Deller’s move from Tulsa, Oklahoma to Seattle, Washington, including reasonable expenses related to the sale of his home in Tulsa. As a temporary adjustment for the difference in the cost of living between Tulsa and Seattle (the “Relocation Adjustment”), for a period of four years (the “Payment Period”) from the Effective Date, the Company has also agreed to pay up to $6,000 a month to Dr. Deller for expenses related to temporary housing and travel to and from Tulsa to Seattle. If Dr. Deller purchases a home in the Seattle area, the Relocation Adjustment will continue to be paid through the expiration of the Payment Period, although the Relocation Adjustment may be adjusted or terminated upon mutual agreement of Dr. Deller and the Company. The Agreement may be terminated by the Company for cause, as defined in the Agreement, due to Dr. Deller’s death or disability, upon 30 days’ notice to Dr. Deller or as a result of a change in control, as defined in the Agreement. With the exception of a termination for cause, if Dr. Deller’s employment is terminated by the Company, aside from accrued but unpaid salary, bonus (if any) and business expenses, Dr. Deller will receive the balance of the unpaid Relocation Adjustment and six months of his annual salary. On January 4, 2019, the Company’s Chief Operating Officer, Dr. Roberto Ruiz, announced his retirement. Dr. Ruiz also entered into a two year consulting contract with the Company in order to ensure a smooth transition of his projects.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	Principles of Consolidation The accompanying consolidated financial statements include the accounts of ClearSign and its subsidiary. Intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Revenue Recognition Cost of Sales and Change in Accounting Principle [Policy Text Block]	Revenue Recognition and Cost of Sales The Company recognizes revenue and related cost of goods sold in accordance with FASB ASC 606 Revenue from Contracts with Customers (ASC 606). Revenues and cost of goods sold are recognized once the goods or services are delivered to the customer’s control and performance obligations are satisfied. Typically, the Company’s contracts with customers have performance obligations regarding air emissions and operational performance that are satisfied upon completion of service. Since this is the singular performance obligation and cannot be achieved until the air emissions and operational performance have been successfully tested, revenue related to the contracts is recognized upon project completion. The Company’s contracts generally include progress payments from the customer upon completion of defined milestones. As these payments are received they are offset against accumulated project costs and recorded as either contract assets or contract liabilities. Upon completion of the performance obligations and acceptance by the customer the projects can be recorded as revenue. The Company's contracts with customers contain no variable considerations or incentives or discounts that would cause revenue to be allocated or adjusted over time. Therefore, no separate methods of evaluating the contracts other than consideration of the price at achievement of the performance objectives was used in satisfying the review requirements of ASC 606. Contract acquisition costs and practical expedients For contracts that have a duration of less than one year, the Company follows ASC 606, practical expedients and expenses those costs when incurred; for contracts with a life exceeding one year, the Company records those costs when performance obligations related to the contract are completed. The Company generally expenses sales commissions when earned. The Company records those costs within general and administrative expenses.
Standard Product Warranty, Policy [Policy Text Block]	Product Warranties The Company warrants all installed products against defects in materials and workmanship for a period specified in each contract by replacing failed parts. Accruals for product warranties are based on historical warranty experience and current product performance trends, and are recorded at the time revenue is recognized as a component of cost of sales. The warranty liabilities are reduced by material and labor costs used to replace parts over the warranty period in the periods in which the costs are incurred. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary, and such adjustments could be material in the future if estimates differ significantly from actual warranty expense. The warranty liabilities are included in accrued liabilities in the balance sheets.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents Highly liquid investments purchased with an original maturity of three months or less are considered cash equivalents. Cash is maintained with a commercial bank where accounts are generally guaranteed by the Federal Deposit Insurance Corporation up to $250,000. The Company’s deposits may at times exceed this limit. The Company also maintains a cash balance in China. Accounts at such banks are insured up to $75,000 (500,000RMB). The Company has not experienced losses in such accounts and believes it is not exposed to any significant credit risk on cash and cash equivalents.
Short Term Investments [Policy Text Block]	Short-Term Investments Short-term investments consist of U.S. Treasury bills with original maturities of twelve months or less and greater than three months. These short-term investments are classified as held to maturity and are recorded on an amortized cost basis which approximates fair value.
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block]	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount. An allowance for doubtful accounts is established, as necessary, based on past experience and other factors which, in management’s judgment, deserve current recognition in estimating bad debts. The determination of the collectability of amounts due from customer accounts requires the Company to make judgments regarding future events and trends. Allowances for doubtful accounts are determined based on assessing the Company’s portfolio on an individual customer and on an overall basis. This process consists of a review of historical collection experience, current aging status of the customer accounts, and the financial condition of the Company’s customers. Based on a review of these factors, the Company may establish or adjust the allowance for specific customers and the accounts receivable portfolio as a whole.
Fixed Assets Policy [Policy Text Block]	Fixed Assets and Leases Fixed assets are recorded at cost. Leases are recorded in accordance with FASB ASC 842 Leases . For those leases with a term greater than one year, the Company recognizes on the balance sheet at the time of lease inception or modification a right-of-use asset and a lease liability, initially measured at the present value of the lease payments. Lease costs are recognized in the income statement over the lease term on a straight-line basis. Operating leases with a term of 1 year or less are recognized on a straight line basis over the term. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are depreciated over the life of the lease or their useful life, whichever is shorter. All other fixed assets are depreciated over two to four years. Maintenance and repairs are expensed as incurred.
Patents and Trademarks Policy [Policy Text Block]	Patents and Trademarks Patents and trademarks are recorded at cost. Amortization is computed using the straight-line method over the estimated useful lives of the assets once they are awarded.
Impairment Of Long Lived Asset Policy [Policy Text Block]	Impairment of Long-Lived Assets The Company tests long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable through the estimated undiscounted cash flows expected to result from the use and eventual disposition of the assets. In that event, a loss is recognized based on the amount by which the carrying amount exceeds the fair value of the long-lived assets. Fair value is determined based on the present value of estimated expected cash flows using a discount rate commensurate with the risks involved, quoted market prices, or appraised values depending upon the nature of the assets. Loss on long-lived assets to be disposed of is determined in a similar manner, except that fair values are reduced for the cost of disposal.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value of Financial Instruments Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities measured at fair value are categorized based on whether or not the inputs are observable in the market and the degree that the inputs are observable. The categorization of financial assets and liabilities within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The three levels of inputs used to establish fair value are the following:  Level 1 – Quoted prices in active markets for identical assets or liabilities;  Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and  Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company's financial instruments primarily consist of cash and cash equivalents, short-term investments, accounts payable and accrued expenses. As of the balance sheet dates, the estimated fair values of the financial instruments were not materially different from their carrying values as presented on the balance sheets. This is primarily attributable to the short-term maturities of these instruments. The Company did not identify any other non-recurring assets and liabilities that are required to be presented in the balance sheets at fair value.
Research and Development Expense, Policy [Policy Text Block]	Research and Development The cost of research and development is expensed as incurred. Research and development costs consist of salaries, benefits, share based compensation, consulting fees, rent, utilities, depreciation, and consumables. In 2018, the Company received $44,000 to partially fund specific research and development activity relating to its ECC technology. Since these funds were provided without expectation of reciprocation, except notification of research results, the funds received were offset against the related research and development costs incurred.
Income Tax, Policy [Policy Text Block]	Income Taxes The Company accounts for income taxes using an asset and liability approach which allows for the recognition and measurement of deferred tax assets based upon the likelihood of realization of tax benefits in future years. Under the asset and liability approach, deferred taxes are provided for the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. A valuation allowance is provided for deferred tax assets if it is more likely than not these items will either expire before the Company is able to realize their benefits, or that future deductibility is uncertain. Tax benefits from an uncertain tax position are recognized only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate resolution.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock-Based Compensation The costs of all employee stock options, as well as other equity-based compensation arrangements, are reflected in the consolidated financial statements based on the estimated fair value of the awards on the grant date. That cost is recognized over the period during which an employee is required to provide service in exchange for the award. Stock compensation for stock granted to non-employees is determined as the fair value of the consideration received or the fair value of equity instruments issued, whichever is more reliably measured.
Foreign Operations [Policy Text Block]	Foreign Operations The accompanying consolidated financial statements as of December 31, 2018 and 2017 include assets amounting to approximately $199,000 and $0, respectively, relating to operations of the Company in China. It is always possible unanticipated events in foreign countries could disrupt the Company’s operations.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency The functional currency of ClearSign Asia Limited is the U.S. dollar. The Company remeasures the transactions denominated in Chinese Yuan at the average exchange rate in effect during the period. At the end of each reporting period, the Company remeasures ClearSign Asia Limited’s monetary assets and liabilities to the U.S. dollar using exchange rates in effect at the end of the reporting period. The Company remeasures its non-monetary assets and liabilities at historical exchange rates. The Company records gains and losses related to remeasurement in other income (expense), net in the consolidated statements of operations. Foreign currency exchange gain (losses) has not been significant in any period presented and the Company has not undertaken any hedging transactions related to foreign currency exposure.
Earnings Per Share, Policy [Policy Text Block]	Net Loss per Common Share Basic loss per share is computed by dividing loss available to common stockholders by the weighted-average number of common shares outstanding. Diluted loss per share is computed similar to basic loss per share except that the denominator is increased to include additional common shares available upon exercise of stock options and warrants using the treasury stock method, except for periods for which no common share equivalents are included because their effect would be anti-dilutive. At December 31, 2018 and 2017, potentially dilutive shares outstanding amounted to 3,376,061 and 3,489,644, respectively.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Standards In May 2017 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2017-09 Scope of Modification Accounting, clarifies Topic 718, Compensation – Stock Compensation , which requires a company to apply modification accounting to changes in the terms or conditions of a share-based payment award unless all of the (1) the fair value of the modified award is the same as the fair value of the original award immediately before the modification. The ASU indicates that if the modification does not affect any of the inputs to the valuation technique used to value the award, the entity is not required to estimate the value immediately before and after the modification; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the modification; and (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the modification. The ASU is effective for all entities for fiscal years beginning after December 15, 2017, including interim periods within those years. The Company currently does not have any modifications to existing stock compensation agreements and will be able to calculate the impact of the ASU once modifications arise. Recently Issued Accounting Pronouncements In June 2018 FASB issued ASU No. 2018-07 Compensation-Stock Compensation. In November 2018 FASB issued ASU 2018-18 Topic 808 Collaborative Arrangements, Management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s consolidated financial statement presentation or disclosures.

Fixed Assets (Tables)

Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Table Text Block]	Fixed assets are summarized as follows: December 31, 2018 2017 Machinery and equipment $ 853,000 $ 801,000 Office furniture and equipment 186,000 167,000 Leasehold improvements 150,000 147,000 Right of use asset-operating leases 637,000 518,000 Accumulated depreciation and amortization (1,369,000 ) (1,135,000 ) $ 457,000 $ 498,000
Schedule Of Leases Cost [Table Text Block]	Lease costs for the years ended December 31, 2018 and 2017 and other quantitative disclosures are as follows: For the years ended December 31, 2018 2017 Lease cost: Operating lease cost $ 218,000 $ 214,000 Short-term lease cost - 47,000 Total lease cost $ 218,000 $ 261,000 Other information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 181,000 Right-of-use assets obtained in exchange for new operating lease liabilities For operating lease: Weighted average remaining lease term (in years) 1.47 Weighted average discount rate 5.56 %
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Minimum future payments under the Company’s leases at December 31, 2018 and their application to the corresponding lease liabilities are as follows: Discounted ‎ lease ‎liability ‎payments Payments ‎ due under ‎lease ‎agreements 2019 216,000 221,000 2020 91,000 92,000 Total $ 307,000 $ 313,000

Patents and Other Intangible _2

Patents and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	Patents and other intangible assets are summarized as follows: December 31, 2018 2017 Patents Patents pending $ 1,202,000 $ 1,167,000 Issued patents 761,000 930,000 1,963,000 2,097,000 Trademarks Trademarks pending 55,000 41,000 Registered trademarks 23,000 23,000 78,000 64,000 Other 8,000 8,000 2,049,000 2,169,000 Accumulated amortization (290,000 ) (313,000 ) $ 1,759,000 $ 1,856,000
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Future amortization expense associated with awarded patents and registered trademarks as of December 31, 2018 is estimated as follows: 2019 $ 169,000 2020 142,000 2021 88,000 2022 62,000 2023 32,000 Thereafter 7,000 $ 500,000

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2018
Product Warranties Disclosures [Abstract]
Schedule of Product Warranty Liability [Table Text Block]	A summary of the Company’s warranty liability activity, which is included in accrued liabilities in the accompanying balance sheets as of December 31, 2018 and 2017, is as follows: 2018 2017 Warranty liability, beginning of year $ 181,000 $ 213,000 Accruals 51,000 69,000 Payments (32,000 ) (114,000 ) Adjustments and other 57,000 13,000 Warranty liability, end of year $ 257,000 $ 181,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	A reconciliation of the expected tax computed at the statutory federal income tax rate to the provision for income taxes is as follows: 2018 2017 Expected tax benefit at 21% $ (1,970,000 ) $ (3,291,000 ) Tax Reform 6,210,000 Change in valuation allowance 1,890,000 (3,070,000 ) Other 80,000 151,000 Provision for income taxes $ - $ -
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	2018 2017 Net operating loss carry forwards $ 11,540,000 $ 9,860,000 Accrued liabilities 280,000 210,000 Stock compensation (50,000 ) (90,000 ) Depreciation 160,000 60,000 Prepaid expenses (20,000 ) (20,000 ) Other - - Deferred tax assets, net 11,910,000 10,020,000 Valuation allowance (11,910,000 ) (10,020,000 ) Net deferred tax asset $ - $ -

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation, Activity [Table Text Block]	A summary of the status of the Company’s non-vested stock options at December 31 and changes during the year is as follows: 2018 2017 Number of ‎ Options Weighted ‎ Average ‎ Date Number of ‎ Options Weighted ‎ Average ‎ Date Non-vested stock options at January 1 238,871 $ 4.27 335,283 $ 5.09 Granted 224,000 $ 1.94 127,000 $ 3.74 Vested (122,647 ) $ 4.15 (207,457 ) $ 5.16 Exercised - - - - Forfeited/Expired/Exchanged (47,909 ) $ 3.82 (15,955 ) $ 5.15 Non-vested stock options at December 31 292,315 $ 2.61 238,871 $ 4.27
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following weighted-average assumptions were utilized in the calculation of the fair value of the stock options: Expected life 6.20 years Weighted average volatility 70 % Forfeiture rate 15 % Weighted average risk-free interest rate 2.74 % Expected dividend rate 0 %
Schedule Of Employee Service Share Based Compensation Unrecognized Period Costs [Table Text Block]	At December 31, 2018, there was $377,000 of total unrecognized compensation cost related to non-vested stock option-based compensation arrangements granted under the Plan. That cost is expected to be recognized in future years as follows: 2019 184,000 2020 119,000 2021 63,000 2022 11,000 $ 377,000
Schedule Of Recognized Compensation Cost [Table Text Block]	The recognized compensation cost associated with the Plan is as follows: 2018 2017 Research and development $ 145,000 $ 119,000 General and administrative 79,000 250,000 Effect on net loss $ 224,000 $ 369,000 Effect on net loss per share $ 0.01 $ 0.02
Schedule Of Share Based Compensation Warrants Activity [Table Text Block]	The following table summarizes the number of warrants, the weighted average exercise price, and weighted average life (in years) by price for both total outstanding warrants and total exercisable warrants at December 31, 2018: Total Outstanding Warrants Exercise Price Warrants Wtd. Avg. ‎ Exercise ‎ Price Remaining ‎ Life ‎ (in years) $1.80 80,000 $ 1.80 2.13 $4.00 2,395,471 $ 4.00 0.07 $10.00 20,313 $ 10.00 0.18 2,495,784 $ 3.98
Equity Incentive Plan [Member]
Share-based Compensation, Activity [Table Text Block]	Activity under the Plan is as follows: 2018 2017 Reserved but unissued shares under the Plan, beginning of year 191,656 266,884 Increases in the number of authorized shares under the Plan 1,106,088 255,261 Grants of stock options (224,000 ) (127,000 ) Stock option forfeitures 337,583 15,955 Exercise of stock options - - Stock grants (114,865 ) (219,444 ) Stock grant forfeitures - - Reserved but unissued shares under the Plan, end of year 1,296,462 191,656
Consultant Plan [Member]
Share-based Compensation, Activity [Table Text Block]	Activity under the Consultant Plan is as follows: 2018 2017 Reserved but unissued shares under the Consultant Plan at January 1 99,159 83,633 Increases in the number of authorized shares under the Consultant Plan 110,546 25,526 Stock grants (10,000 ) (10,000 ) Reserved but unissued shares under the Consultant Plan at Period End 199,705 99,159
Warrant [Member]
Schedule Of Share Based Compensation Warrants Activity [Table Text Block]	A summary of the Company’s warrant activity and related information is as follows: 2018 2017 Warrants Weighted ‎ Average ‎ Exercise ‎ Price Warrants Weighted ‎ Average ‎ Exercise ‎ Price Outstanding at January 1 2,495,784 $ 3.98 445,313 $ 4.65 Granted - - 2,395,471 $ 4.00 Exercised - - - - Forfeited/Expired - - (345,000 ) $ 5.00 Outstanding at Period End 2,495,784 $ 3.98 2,495,784 $ 3.98
Employee Stock Option [Member]
Share-based Compensation, Stock Options, Activity [Table Text Block]	A summary of the Company’s stock option activity and related information is as follows: 2018 2017 Options to ‎ Purchase ‎ Common ‎ Stock Weighted ‎ Average ‎ Exercise ‎ Price Weighted ‎ Average ‎ Remaining ‎ Contractual ‎ Life (in ‎ years) Options to ‎ Purchase ‎ Common ‎ Stock Weighted ‎ Average ‎ Exercise ‎ Price Weighted ‎ Average ‎ Remaining ‎ Contractual ‎ Life (in ‎ years) Outstanding at January 1 993,860 $ 4.81 6.94 882,815 $ 4.98 7.51 Granted 224,000 $ 1.94 9.23 127,000 $ 3.69 9.48 Exercised - - - - - - Forfeited/Expired/Exchanged (337,583 ) $ 4.19 - (15,955 ) $ 5.15 - Outstanding at December 31 880,277 $ 4.32 9.04 993,860 $ 4.81 6.94 Exercisable at December 31 587,962 $ 5.17 6.49 754,989 $ 4.98 6.32

Quarterly Results (Tables)

Quarterly Results (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Table Text Block]	Quarterly results for the years ended December 31, 2018 and 2017 are as follows: First Second Third Fourth Quarter Quarter Quarter Quarter For the year ended December 31, 2018 Revenue $ 530,000 $ - $ - $ - Gross Profit (Loss) $ 135,000 $ (20,000 ) $ (9,000 ) $ (3,000 ) Operating Expense $ 2,413,000 $ 2,370,000 $ 2,306,000 $ 2,585,000 Net Loss $ (2,278,000 ) $ (2,389,000 ) $ (2,292,000 ) $ (2,541,000 ) Net Loss per share - basic and fully diluted $ (0.13 ) $ (0.11 ) $ (0.09 ) $ (0.10 ) For the year ended December 31, 2017 Revenue $ 360,000 $ - $ - $ 180,000 Gross Profit (Loss) $ 109,000 $ - $ (15,000 ) $ 66,000 Operating Expense $ 2,502,000 $ 2,251,000 $ 2,460,000 $ 2,659,000 Net Loss $ (2,379,000 ) $ (2,236,000 ) $ (2,472,000 ) $ (2,593,000 ) Net Loss per share - basic and fully diluted $ (0.16 ) $ (0.17 ) $ (0.16 ) $ (0.17 )

Organization and Description _2

Organization and Description of Business (Details Textual) - USD ($)	1 Months Ended
	Jul. 20, 2018	Feb. 27, 2018	Dec. 31, 2018	Dec. 31, 2017
Organization and Description of Business [Line Items]
Proceeds from Issuance of Common Stock	$ 11,600,000	$ 11,900,000
Accumulated deficit			$ (59,511,000)	$ (50,011,000)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2018CNY (¥)
Variable Interest Entity [Line Items]
Cash, FDIC Insured Amount	$ 250,000
Weighted Average Number of Shares Outstanding, Diluted | shares	3,376,061	3,489,644
Tax Benefits Recognized Description	The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate resolution.
Property, Plant and Equipment, Estimated Useful Lives	over two to four years
Assets	$ 18,637,000	$ 4,161,000
Funds Received	44,000
CHINA
Variable Interest Entity [Line Items]
Cash, FDIC Insured Amount	75,000		¥ 500,000
Assets	$ 199,000	$ 0

Fixed Assets (Details)

Fixed Assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Machinery and equipment	$ 853,000	$ 801,000
Office furniture and equipment	186,000	167,000
Leasehold improvements	150,000	147,000
Right of use asset-operating leases	637,000	518,000
Accumulated depreciation and amortization	(1,369,000)	(1,135,000)
Property, Plant and Equipment, Net, Total	$ 457,000	$ 498,000

Fixed Assets (Details 1)

Fixed Assets (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Lease cost:
Operating lease cost	$ 218,000	$ 214,000
Short-term lease cost	0	47,000
Total lease cost	$ 218,000	261,000
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		$ 181,000
For operating lease:
Weighted average remaining lease term (in years)		1 year 5 months 19 days
Weighted average discount rate		5.56%

Fixed Assets (Details 2)

Fixed Assets (Details 2)	Dec. 31, 2018USD ($)
Discounted Lease Liabilities Payments [Member]
2019	$ 216,000
2020	91,000
Total	307,000
Payments Due Under Lease Agreement [Member]
2019	221,000
2020	92,000
Total	$ 313,000

Fixed Assets (Details Textual)

Fixed Assets (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating Lease, Cost	$ 6,000	$ 6,000
Lease One [Member]
Triple Net Operating Cost	12,000
Lease Two [Member]
Triple Net Operating Cost	$ 2,000

Patents and Other Intangible _3

Patents and Other Intangible Assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Patents	$ 1,963,000	$ 2,097,000
Trademarks	78,000	64,000
Other	8,000	8,000
Patents and other intangible assets	2,049,000	2,169,000
Accumulated amortization	(290,000)	(313,000)
Finite-Lived Intangible Assets, Net	1,759,000	1,856,000
Patents Pending [Member]
Patents	1,202,000	1,167,000
Issued Patents [Member]
Patents	761,000	930,000
Trademarks Pending [Member]
Trademarks	55,000	41,000
Registered Trademarks [Member]
Trademarks	$ 23,000	$ 23,000

Patents and Other Intangible _4

Patents and Other Intangible Assets (Details 1) - Patents [Member]	Dec. 31, 2018USD ($)
Finite-Lived Intangible Assets [Line Items]
2019	$ 169,000
2020	142,000
2021	88,000
2022	62,000
2023	32,000
Thereafter	7,000
Finite-Lived Intangible Assets, Net	$ 500,000

Patents and Other Intangible _5

Patents and Other Intangible Assets (Detail Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Asset Impairment Charges	$ 322,000	$ 0

Sales, Contract Assets and Co_2

Sales, Contract Assets and Contract Liabilities (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Contract with Customer, Asset, Net, Current	$ 39,000	$ 184,000
Contract with Customer, Liability, Current	0
Once Through Steam Generator [Member]
Revenue from Contract with Customer, Including Assessed Tax	128,000
Small Project [Member]
Revenue from Contract with Customer, Including Assessed Tax	42,000
California oil producer [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 360,000

Product Warranties (Details)

Product Warranties (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Product Warranty Liability [Line Items]
Warranty liability, beginning of year	$ 181,000	$ 213,000
Accruals	51,000	69,000
Payments	(32,000)	(114,000)
Adjustments and other	57,000	13,000
Warranty liability, end of year	$ 257,000	$ 181,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Tax Reconciliation [Line Items]
Expected tax benefit at 21%		$ (1,970,000)	$ (3,291,000)
Tax Reform	$ 6,200,000		6,210,000
Change in valuation allowance		1,890,000	(3,070,000)
Other		80,000	151,000
Provision for income taxes		$ 0	$ 0

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Income Tax Reconciliation [Line Items]
Net operating loss carry forwards	$ 11,540,000	$ 9,860,000
Accrued liabilities	280,000	210,000
Stock compensation	(50,000)	(90,000)
Depreciation	160,000	60,000
Prepaid expenses	(20,000)	(20,000)
Other	0	0
Deferred tax assets, net	11,910,000	10,020,000
Valuation allowance	(11,910,000)	(10,020,000)
Net deferred tax asset	$ 0	$ 0

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%
Limitation In Carry Forward Percentage Of Net Operating Loss		50.00%
Net Operating Losses For Tax Purposes		$ 55,000,000
Operating Loss Carryforward Expiration Date		The net operating loss carry forwards may be used to reduce taxable income through the years 2028 to 2038.
Deferred tax assets, net		$ 11,910,000	$ 10,020,000
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 6,200,000		$ 6,210,000

Stockholders' Equity (Details)

Stockholders' Equity (Details) - Equity Incentive Plan [Member] - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reserved but unissued shares under the Plan, beginning of year	191,656	266,884
Increases in the number of authorized shares under the Plan	1,106,088	255,261
Grants of stock options	(224,000)	(127,000)
Stock option forfeitures	337,583	15,955
Exercise of stock options	0	0
Stock grants	(114,865)	(219,444)
Stock grant forfeitures	0	0
Reserved but unissued shares under the Plan, end of year	1,296,462	191,656

Stockholders' Equity (Details 1

Stockholders' Equity (Details 1) - Employee Stock Option [Member]	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years 2 months 12 days
Weighted average volatility	70.00%
Forfeiture rate	15.00%
Weighted average risk-free interest rate	2.74%
Expected dividend rate	0.00%

Stockholders' Equity (Details 2

Stockholders' Equity (Details 2) - Employee Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Reserved but unissued shares under the Plan, beginning of year	993,860	882,815
Granted - Options to Purchase Common Stock	224,000	127,000
Exercised - Options to Purchase Common Stock	0	0
Forfeited/Expired/Exchanged - Options to Purchase Common Stock	(337,583)	(15,955)
Reserved but unissued shares under the Plan, end of year	880,277	993,860	882,815
Exercisable - Options to Purchase Common Stock	587,962	754,989
Outstanding - Weighted Average Exercise Price	$ 4.81	$ 4.98
Granted - Weighted Average Exercise Price	1.94	3.69
Exercised - Weighted Average Exercise Price	0	0
Forfeited/Expired/Exchanged - Weighted Average Exercise Price	4.19	5.15
Outstanding - Weighted Average Exercise Price	4.32	4.81	$ 4.98
Exercisable - Weighted Average Exercise Price	$ 5.17	$ 4.98
Granted - Weighted Average Remaining Contractual Life (in years)	9 years 2 months 23 days	9 years 5 months 23 days
Exercised - Weighted Average Remaining Contractual Life (in years)	0 years	0 years
Forfeited/Expired/Exchanged - Weighted Average Remaining Contractual Life (in years)	0 years	0 years
Outstanding - Weighted Average Remaining Contractual Life (in years)	9 years 14 days	6 years 11 months 8 days	7 years 6 months 4 days
Exercisable - Weighted Average Remaining Contractual Life (in years)	6 years 5 months 26 days	6 years 3 months 25 days

Stockholders' Equity (Details 3

Stockholders' Equity (Details 3) - Employee Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Non-vested stock options at January 1	238,871	335,283
Granted - Number of Options	224,000	127,000
Vested - Number of Options	(122,647)	(207,457)
Exercised - Number of Options	0	0
Forfeited/Expired/Exchanged - Number of Options	(47,909)	(15,955)
Non-vested stock options at December 31	292,315	238,871
Non-vested stock options - Weighted Average Grant Date Fair Value	$ 4.27	$ 5.09
Granted - Weighted Average Grant Date Fair Value	1.94	3.74
Vested - Weighted Average Grant Date Fair Value	4.15	5.16
Exercised - Weighted Average Grant Date Fair Value	0	0
Forfeited/Expired/Exchanged - Weighted Average Grant Date Fair Value	3.82	5.15
Non-vested stock options - Weighted Average Grant Date Fair Value	$ 2.61	$ 4.27

Stockholders' Equity (Details 4

Stockholders' Equity (Details 4)	12 Months Ended
	Dec. 31, 2018USD ($)
Other General and Administrative Expense	$ 377,000
Year 2019 [Member]
Other General and Administrative Expense	184,000
Year 2020 [Member]
Other General and Administrative Expense	119,000
Year 2021 [Member]
Other General and Administrative Expense	63,000
Year 2022 [Member]
Other General and Administrative Expense	$ 11,000

Stockholders' Equity (Details 5

Stockholders' Equity (Details 5) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Effect on net loss	$ 224,000	$ 369,000
Effect on net loss per share (in dollars per share)	$ 0.01	$ 0.02
Research and development [Member]
Effect on net loss	$ 145,000	$ 119,000
General and administrative [Member]
Effect on net loss	$ 79,000	$ 250,000

Stockholders' Equity (Details 6

Stockholders' Equity (Details 6) - Consultant Plan [Member] - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reserved but unissued shares under the Plan, beginning of year	99,159	83,633
Increases in the number of authorized shares under the Consultant Plan	110,546	25,526
Stock grants	(10,000)	(10,000)
Reserved but unissued shares under the Plan, end of year	199,705	99,159

Stockholders' Equity (Details 7

Stockholders' Equity (Details 7) - Warrant [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Outstanding - Warrants	2,495,784	445,313
Granted - Warrants	0	2,395,471
Exercised - Warrants	0	0
Forfeited/Expired - Warrants	0	(345,000)
Outstanding - Warrants	2,495,784	2,495,784
Outstanding - Average Exercise Price at beginning of year	$ 3.98	$ 4.65
Granted - Average Exercise Price	0	4
Exercised - Average Exercise Price	0	0
Forfeited/Expired - Average Exercise Price	0	5
Outstanding - Exercise Price at end of year	$ 3.98	$ 3.98

Stockholders' Equity (Details 8

Stockholders' Equity (Details 8)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Warrants Outstanding | shares	2,495,784
Warrants Outstanding Weighted Average Exercise Price	$ 3.98
Exercise Price 1.80 [Member]
Warrants Exercise Price	$ 1.80
Warrants Outstanding | shares	80,000
Warrants Outstanding Weighted Average Exercise Price	$ 1.80
Warrants Outstanding Remaining Life (in years)	2 years 1 month 17 days
Exercise Price 4.00 [Member]
Warrants Exercise Price	$ 4
Warrants Outstanding | shares	2,395,471
Warrants Outstanding Weighted Average Exercise Price	$ 4
Warrants Outstanding Remaining Life (in years)	25 days
Exercise Price 10.00 [Member]
Warrants Exercise Price	$ 10
Warrants Outstanding | shares	20,313
Warrants Outstanding Weighted Average Exercise Price	$ 10
Warrants Outstanding Remaining Life (in years)	2 months 5 days

Stockholders' Equity (Details T

Stockholders' Equity (Details Textual) - USD ($)	1 Months Ended				12 Months Ended
	Jul. 31, 2018	Feb. 28, 2018	Feb. 27, 2018	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Stock Issued During Period, Value, New Issues						$ 7,258,000
Common Stock, Shares Authorized					62,500,000
Preferred Stock, Shares Authorized					2,000,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized					$ 377,000
Stock Option Plan Description					The Consultant Plan provides for quarterly increases in the available number of authorized shares equal to the lesser of 1% of any new shares issued by the Company during the quarter immediately prior to the adjustment date or such lesser amount as the Board of Directors shall determine.
Stock Granted, Value, Share-based Compensation, Gross	$ 11,700,000
General And Administrative Expense Related To Stock Grant					$ 212,000
Proceeds from Issuance or Sale of Equity					23,511,000	$ 8,667,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value					$ 0
Other Underwriting Expense				$ 60,000
Share Price				$ 3.03
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.97
Stock Issued During Period In Payment Of Accrued Compensation Per Share			$ 3.60			$ 3.60
Stock Issued During Period Value In Payment Of Accrued Compensation		$ 490,000				$ 490,000
Common Stock, Par or Stated Value Per Share					$ 0.0001	$ 0.0001
General and Administrative Expense					$ 5,622,000	$ 5,160,000
Warrants Intrinsic Value Outstanding					$ 0
Stock Issued During Period, Shares, New Issues	5,213,543
Proceeds from Issuance of Private Placement	$ 11,600,000
Sale of Stock, Price Per Share	$ 4
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	478,854
Equity Method Investment Ownership Percentage Description	In no event may the Participation Right be exercised to the extent it would cause the Investor or any of its affiliates to beneficially own 20% or more of the Company's then outstanding common stock or hold shares with 20% or more of the voting power.
Underwritten Public Offering [Member]
Class of Stock [Line Items]
Stock Issued During Period, Value, New Issues				$ 9.6
Proceeds from Issuance or Sale of Equity				$ 8.7
Offering [Member]
Class of Stock [Line Items]
Proceeds from Issuance or Sale of Equity		$ 11,900,000
Stock Issued During Period, Shares, Other				2,395,471
Shares Issued, Price Per Share	$ 2.25	$ 2.25		$ 4
Warrants Authorized For Issuance To Acquire Common Stock Shares Number		5,750,000		2,395,471
Employee Stock Option [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					224,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term2					10 years
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price					$ 1.94
Allocated Share-based Compensation Expense					$ 43,000
Employee Stock Option [Member] | Minimum [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 1.85
Employee Stock Option [Member] | Maximum [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 2.10
General and Administrative Expense [Member]
Class of Stock [Line Items]
General and Administrative Expense						$ 300,000
Stock Issued During Period, Shares, New Issues					114,865
Consultant Plan [Member]
Class of Stock [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance					199,705
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					7,500	10,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 3.50
General And Administrative Expense Related To Stock Grant					$ 26,000	$ 35,000
Consultant Plan Expenses					$ 30,000	42,000
Consultant Plan [Member] | Employee Stock Option [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					236,000
Consultant Plan Two [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					10,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 1.44
General And Administrative Expense Related To Stock Grant					$ 4,000
Share Based Compensation Arrangement By Share Based Payment Award Options Value Grants In Period Weighted Average Grant Date Fair Value					$ 14,000
General And Administrative Expense Related To Stock Grant In Shares					2,500
Common Stock [Member]
Class of Stock [Line Items]
Stock Issued During Period, Value, New Issues						$ 1,000
Stock Issued During Period, Shares, Other					10,963,543
Stock issued During Period Shares In Payment Of Accrued Compensation		136,110				136,110
Stock Issued During Period Value In Payment Of Accrued Compensation						$ 0
Stock Issued During Period Shares Issued For 2017 Board Services						83,334
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercised In Period						3.60
Stock Issued During Period, Shares, New Issues						2,395,471
Warrant [Member]
Class of Stock [Line Items]
Exercise Price Of Warrants				$ 4
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercised In Period					0	0
Equity Incentive Plan [Member]
Class of Stock [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Purchase Price Share Minimum					85.00%
Common Stock, Capital Shares Reserved for Future Issuance					2,768,618
Increase Decrease Of Share Based Compensation Arrangement By Share Based Payment Award Percentage					10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					224,000	127,000
Mdb Consulting Services [Member]
Class of Stock [Line Items]
Underwriting Expense				$ 915,000
Payments for Underwriting Expense				575,000
Other Underwriting Expense				$ 60,000
Mr Pirnat [Member]
Class of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term2					2 years

Retirement Plan (Details Textua

Retirement Plan (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Retirement Plan [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	3.00%	3.00%
Defined Contribution Plan, Cost	$ 85,000	$ 86,000

Related Party Transactions (Det

Related Party Transactions (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018
Related Party Transaction [Line Items]
Consulting Fee	$ 575,000
Other Underwriting Expense	$ 60,000
Reimbursement Payable Included In Accounts Payable And Accrued Liabilities		$ 40,000
Related Party Transaction, Expenses from Transactions with Related Party		$ 364,000

Quarterly Results (Details)

Quarterly Results (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information [Line Items]
Revenue	$ 0	$ 0	$ 0	$ 530,000	$ 180,000	$ 0	$ 0	$ 360,000	$ 530,000	$ 540,000
Gross Profit (Loss)	(3,000)	(9,000)	(20,000)	135,000	66,000	(15,000)	0	109,000	103,000	160,000
Operating Expense	2,585,000	2,306,000	2,370,000	2,413,000	2,659,000	2,460,000	2,251,000	2,502,000	9,674,000	9,872,000
Net Loss	$ (2,541,000)	$ (2,292,000)	$ (2,389,000)	$ (2,278,000)	$ (2,593,000)	$ (2,472,000)	$ (2,236,000)	$ (2,379,000)	$ (9,500,000)	$ (9,680,000)
Net Loss per share - basic and fully diluted (in dollars per share)	$ (0.10)	$ (0.09)	$ (0.11)	$ (0.13)	$ (0.17)	$ (0.16)	$ (0.17)	$ (0.16)	$ 0.42	$ 0.63

Subsequent Event (Details Textu

Subsequent Event (Details Textual) - USD ($)	1 Months Ended
	Jan. 28, 2019	Feb. 20, 2019
Share-based Compensation Award, Tranche One [Member]
Subsequent Event [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	400,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price	$ 1.16
Share-based Compensation Award, Tranche Two [Member]
Subsequent Event [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price		$ 2.25
Employment Contracts [Member]
Subsequent Event [Line Items]
Supplemental Unemployment Benefits, Salary Continuation	$ 350,000
Employment Early Termination Relocation expense	100,000
Employment Early Termination Living Allowance Per Month	$ 6,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term	10 years