| Summary of Significant Accounting Policies (Policies) | 9 Months Ended |
| Sep. 30, 2023 |
| Summary of Significant Accounting Policies | |
| Basis of Presentation | Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) for Form 10-Q. Accordingly, certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet at December 31, 2022 has been derived from the Company’s audited financial statements as of that date. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring and other adjustments necessary for a fair presentation. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Operating results for interim periods are not necessarily indicative of operating results for an entire fiscal year or any other future periods. The accompanying unaudited condensed consolidated financial statements include the accounts of ClearSign and its subsidiary. Intercompany balances and transactions have been eliminated in consolidation. |
| Use of Estimates | 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 the 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 | Revenue Recognition and Cost of Sales The Company recognizes revenue and related cost of goods sold in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification Topic 606 Revenue from Contracts with Customers 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 collectability is determined, revenue is recorded. For any contract that is expected to incur costs in excess of the contract price, the Company accrues the estimated loss in full in the period such determination is made. |
| Contract Costs | Contract Costs The Company capitalizes project costs until performance obligations related to the contract are completed. The Company expenses selling and marketing expenses when incurred within the statements of operations in general and administrative expenses. |
| Product Warranties | 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 or expected warranty experience and current product performance trends and are recorded as a component of cost of sales at the time revenue is recognized. 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. Product warranties are included in accounts payable and accrued liabilities in the consolidated balance sheets. |
| Cash and Cash Equivalents | Cash and Cash Equivalents Cash and cash equivalents consist of cash on deposit in a checking and savings account, and short-term money market instruments with an original maturity of three months or less. Cash equivalents, which consist of short-term U.S. treasury bills, are based on quoted market prices, a Level 1 fair value measure. |
| Short-term Investments | Short-Term Investments Short-term investments consist of U.S. treasuries 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 based on the Company’s positive intent and ability to hold these securities to maturity. As of September 30, 2023, the Company has not experienced any other-than-temporary impairment of its short-term investments. A decline in the market value of any held-to-maturity security below cost that is deemed other than temporary results in a reduction in carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. The company evaluates whether the decline in fair value of its investments is other-than temporary at each quarter-end. The cost basis for the Company’s short-term investments totaled approximately zero and $2,606 thousand as of September 30, 2023 and December 31, 2022, respectively. The unrealized holding gains for the Company’s short-term investments totaled approximately zero and $4 thousand as of September 30, 2023 and December 31, 2022, respectively. The Company has not experienced any continuous unrealized holding losses on these investments. The fair value for the Company’s short-term investments totaled approximately zero and $2,610 thousand as of September 30, 2023 and December 31, 2022, respectively. |
| Accounts Receivable and Allowance for Doubtful Accounts | Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the contractual invoiced amount. An allowance for doubtful accounts is established, as necessary, based on past experience and management’s judgment. The determination of the collectability of amounts due from customers require 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 and Leases Fixed assets are recorded at cost. Leases are recorded in accordance with FASB ASC 842, Leases whichever is shorter. All other fixed assets are depreciated over three |
| Patents and Trademarks | Patents and Trademarks Third-party expenses related to patents and trademarks are recorded at cost, less accumulated amortization. Amortization is computed using the straight-line method over the estimated useful lives of the assets once they are awarded. Patent application costs are deferred pending the outcome of patent and trademark applications. Costs associated with unsuccessful patent applications and abandoned intellectual property are expensed when determined to have no continuing value in current business activity. The Company evaluates the recoverability of the carrying values of intangible assets each reporting period. |
| Impairment of Long-lived Assets | Impairment of Long-Lived Assets The Company tests long-lived assets, consisting of fixed assets, patents, trademarks, and other intangible 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 from the use and eventual disposition of the assets. In the event an asset is not fully recoverable, 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. Losses on long-lived assets to be disposed are determined in a similar manner, except those fair values are reduced for the cost of disposal. |
| Fair Value of Financial Instruments | 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 equivalents, short-term investments, accounts receivable, contract assets, contract liabilities, 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 nature of these instruments. The Company did not identify any other recurring or non-recurring assets and liabilities that are required to be presented in the balance sheets at fair value. |
| Research and Development | Research and Development The cost of research and development is expensed as incurred. Research and development costs consist of salaries, benefits, share based compensation, consumables, and consulting fees, including costs to develop and test prototype equipment and parts. Research and Development costs have been offset by funds received, if any, from strategic partners in cost sharing, collaborative projects. During the nine months ended September 30, 2023, the Company received $60 thousand from these arrangements. During the nine months ended September 30, 2022, the Company did not receive funds from these arrangements. |
| Government Assistance | Government Assistance The Company has adopted Accounting Standards Update (“ASU”) 2021-10, Government Assistance (Topic 832) Disclosures by Business Entities about Government Assistance, which requires footnote disclosure of assistance received from government entities. The Company records gross monies received from government entities in other income, and associated expenses such as salaries and supplies are recorded in Research and Development or General and Administration, depending on the nature of expenditure. The Company accrues for reimbursement requests submitted to government entities in accounts receivable. |
| Income Taxes | 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 the Company would not be able to realize their benefits, or that future deductibility is uncertain. Tax benefits are recognized only if it is more likely than not that the tax benefits will be utilized in the foreseeable future. |
| Share-Based Compensation | Share-Based Compensation The costs of all employee stock options, as well as other equity-based compensation arrangements, are reflected in the unaudited condensed 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, or in the case of performance options, expense is recognized upon completion of milestones as defined in the grant agreement. Share-based compensation for stock grants 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 | Foreign Operations The accompanying unaudited condensed consolidated balance sheets as of September 30, 2023 and December 31, 2022 include assets amounting to approximately $261 thousand and $172 thousand, respectively, relating to operations of ClearSign Asia Limited. The Beijing registered capital requirement is $350 thousand, which is required to be paid by 2027, and of which $111 thousand has been paid as of September 30, 2023. It is always possible that unanticipated events in foreign countries could disrupt the Company’s operations, and since the first quarter of 2020 this has been and currently continues to be the case with the effects of the COVID-19 pandemic. |
| Foreign Currency | Foreign Currency Assets and liabilities of ClearSign Asia Limited with non-U.S. Dollar functional currency are translated to U.S. Dollars using exchange rates in effect at the end of the period. Revenue and expenses are translated to U.S. Dollars using rates that approximate those in effect during the period. The resulting translation adjustments are included in the Company’s condensed consolidated balance sheets in the stockholders’ equity section as a component of accumulated other comprehensive income (loss). |
| Net Loss per Common Share | 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 September 30, 2023 and September 30, 2022, potentially dilutive shares outstanding amounted to 4.0 million and 3.1 million, respectively. |
| Recently Issued Accounting Pronouncements Adopted | Recently Issued Accounting Pronouncements Adopted In June 2017, the FASB issued an Accounting Standards Update (“ASU”) ASU 2016-13, Financial Instruments (Topic 326) Measurement of Credit Losses on Financial Instruments |
