Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The unaudited condensed consolidated financial statements include the accounts of the Company and its subsidiary Energy Focus LED Solutions, LLC, which is not active. Unless indicated otherwise, the information in the accompanying financial statements and notes to the unaudited condensed consolidated financial statements relates to our continuing operations. We have prepared the accompanying financial data for the three months ended March 31, 2019 and 2018 pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. The accompanying financial data and information should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2018 (“2018 Annual Report”). The Condensed Consolidated Balance Sheet as of December 31, 2018 has been derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying financial statements contain all normal and recurring adjustments necessary to present fairly our Condensed Consolidated Balance Sheets as of March 31, 2019 and December 31, 2018, Condensed Consolidated Statements of Operations for the three months ended March 31, 2019 and 2018, Condensed Consolidated Statements of Comprehensive Loss for the three months ended March 31, 2019 and 2018, Condensed Consolidated Statements of Changes in Stockholders’ Equity for the three months ended March 31, 2019 and 2018, and Condensed Consolidated Statements of Cash Flows for the three months ended March 31, 2019 and 2018. Other than the adoption of the new lease accounting standard, there have been no other material changes to our significant accounting policies, as compared to those described in our 2018 Annual Report.
Use of estimates	Use of estimates The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in our financial statements and accompanying notes. Management bases its estimates on historical experience and various other assumptions believed to be reasonable. Although these estimates are based on management’s best knowledge of current events and actions that may impact us in the future, actual results may vary from the estimates. Estimates include, but are not limited to, the establishment of reserves for accounts receivable, sales returns, inventory obsolescence and warranty claims; the useful lives of property and equipment; valuation allowance for net deferred taxes; the cost and offsetting income related to subleased property; and stock-based compensation. In addition, estimates and assumptions associated with the determination of the fair value of financial instruments and evaluation of long-lived assets for impairment requires considerable judgment. Actual results could differ from those estimates and such differences could be material.
Reclassifications	Reclassifications Certain amounts related to warranty accruals and settlements were reclassified to conform to current period reporting presentation with no impact on financial position, loss from operations or cash used in operations.
Certain risks and concentrations	Certain risks and concentrations We have certain customers whose net sales individually represented 10 percent or more of our total net sales, or whose net trade accounts receivable balance individually represented 10 percent or more of our total net trade accounts receivable, as follows: For the three months ended March 31, 2019, sales to our primary distributor for the U.S. Navy, a shipbuilder for the U.S. Navy, and a regional commercial lighting retrofit company located in Texas accounted for approximately 22 percent, 10 percent, and 30 percent of net sales, respectively. When sales to our primary distributor for the U.S. Navy are combined with sales to a shipbuilder for the U.S. Navy, total sales of products for the U.S. Navy comprised approximately 32 percent of net sales for the same period. For the three months ended March 31, 2018, sales to our primary distributor for the U.S. Navy accounted for approximately 46 percent of net sales for the period. When combined with sales to a shipbuilder for the U.S. Navy, sales of products for the U.S. Navy comprised approximately 50 percent of net sales for the same period. Additionally, a regional commercial lighting retrofit company located in California accounted for approximately 10 percent of net sales for the three months ended March 31, 2018. A regional commercial lighting retrofit company located in Texas, our primary distributor for the U.S. Navy, and a primary shipbuilder for the U.S. Navy, accounted for approximately 34 percent, 19 percent, and 14 percent of net trade accounts receivable, respectively, at March 31, 2019. At December 31, 2018, our primary distributor for the U.S. Navy accounted for approximately 40 percent of net trade accounts receivable.
Recent accounting pronouncements	Recent accounting pronouncements In August 2018, the Financial Accounting Standards Board (“FASB) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles--Goodwill and Other--Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for capitalizing implementation costs in a cloud computing service contract with the requirements for capitalizing implementation costs incurred for an internal-use software license. This standard will be effective for interim and annual periods beginning after December 15, 2019. We do not expect the adoption of this guidance to have a significant impact on our financial position, results of operations or cash flows. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which significantly changes the accounting for credit losses on instruments within its scope. The new guidance introduces an approach based on expected losses to estimate credit losses on certain financial instruments, including trade receivables, and requires an entity to recognize an allowance based on its estimate of expected credit losses rather than incurred losses. This standard will be effective for interim and annual periods beginning after December 15, 2019, and will generally require adoption on a modified retrospective basis. We are in the process of evaluating the impact of the standard. Adoption of recent accounting pronouncement In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which supersedes the current lease accounting requirements. Additionally, in July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, which simplifies adoption of Topic 842 by allowing an additional transition method that will not require restatement of prior periods and providing a new practical expedient for lessors to avoid separating lease and non-lease components within a contract if certain criteria are met (provisions of which must be elected upon adoption of Topic 842). The new standard requires a lessee to record on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than 12 months. It also requires lessees to disclose certain key information about lease transactions. Upon implementation, an entity’s lease payment obligations will be recognized at their estimated present value along with a corresponding right-of-use asset. Lease expense recognition will be generally consistent with current practice. The Company adopted this guidance as of January 1, 2019 using the required modified retrospective method with the non-comparative transition option. The Company applied the transitional package of practical expedients allowed by the standard to not reassess the identification, classification and initial direct costs of leases commencing before this ASU’s effective date. The Company also applied the lease term and impairment hindsight transitional practical expedients. The Company has chosen to apply the following accounting policy practical expedients: to not separate lease and non-lease components to new leases as well as existing leases through transition; and the election to not apply recognition requirements of the guidance to short-term leases. The results for reporting periods beginning after January 1, 2019 are presented under Topic 842, while prior period amounts are not adjusted and continue to be reported in accordance with legacy generally accepted accounting principles. On adoption, we recognized additional operating lease liabilities of approximately $2.9 million, with corresponding right-of-use assets based on the present value of the remaining minimum rental payments under prior leasing standards for our existing operating leases. The operating lease right-of-use assets recorded upon adoption were offset by the carrying value of liabilities previously recorded under Topic 420 and impairment charges totaling $273 thousand and $186 thousand, respectively. Refer to Note 6, “Leases” below for additional disclosures relating to the Company’s leasing arrangements.
Revenue	Revenue On January 1, 2018, we adopted ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), as amended by subsequently issued additional guidance (together, “ASC 606”) using the modified retrospective method. The adoption of ASC 606 did not have a material impact on our consolidated financial position or results of operations, as our revenue arrangements generally consist of a single performance obligation to transfer promised goods at a fixed price. Net sales include revenues from sales of products and shipping and handling charges, net of estimates for product returns. Revenue is measured at the amount of consideration we expect to receive in exchange for the transferred products. We recognize revenue at the point in time when we transfer the promised products to the customer and the customer obtains control over the products. We recognize revenue for shipping and handling charges at the time the goods are shipped to the customer, and the costs of outbound freight are included in cost of sales, as we have elected the practical expedient included in ASC 606. We provide for product returns based on historical return rates. While we incur costs for sales commissions to our sales employees and outside agents, we recognize commission costs concurrent with the related revenue, as the amortization period is less than one year and we have elected the practical expedient included in ASC 606. We do not incur any other incremental costs to obtain contracts with our customers. Our product warranties are assurance-type warranties, which promise the customer that the products are as specified in the contract. Therefore, the product warranties are not a separate performance obligation and are accounted for as described below. Sales taxes assessed by governmental authorities are accounted for on a net basis and are excluded from net sales.
Accounts Receivable	Accounts Receivable Our trade accounts receivable consists of amounts billed to and currently due from customers. Credit is extended to customers based upon an evaluation of the customer’s financial condition and the amounts due are stated at their estimated net realizable value. We maintain an allowance for doubtful accounts receivable to provide for the estimated amount of receivables that will not be collected. The allowance is based on an assessment of customer creditworthiness and historical payment experience, the age of outstanding receivables, and performance guarantees to the extent applicable. Past due amounts are written off when our internal collection efforts have been unsuccessful. Our standard payment terms with customers are net 30 days, and we do not generally offer extended payment terms to our customers, but exceptions are made in some cases to major customers or with particular orders. Accordingly, we do not adjust trade accounts receivable for the effects of financing, as we expect the period between the transfer of product to the customer and the receipt of payment from the customer to be in line with our standard payment terms.
Net loss per share	Net loss per share Basic loss per share is computed by dividing net loss available to common stockholders by the weighted average number of common shares outstanding during the period, excluding the effects of any potentially dilutive securities. Diluted loss per share gives effect to all dilutive potential common shares outstanding during the period. Dilutive potential common shares consist of incremental shares upon the exercise of stock options or release of restricted stock units unless the effect would be anti-dilutive.
Product warranties	Product warranties Through March 31, 2016, we warranted finished goods against defects in material and workmanship under normal use and service for periods generally between one and five years. Beginning April 1, 2016, we warrant our commercial LED tubes, globes, and troffer luminaires for a period of ten years. Warranty settlement costs consist of actual amounts expensed for warranty, which are largely a result of the cost of replacement products provided to our customers. A liability for the estimated future costs under product warranties is maintained for products outstanding under warranty based on the actual claims incurred to date and the estimated nature, frequency, and costs of future claims. These estimates are inherently uncertain and changes to our historical or projected experience may cause material changes to our warranty reserves in the future. We continuously review the assumptions related to the adequacy of our warranty reserve, including product failure rates, and make adjustments to the existing warranty liability when there are changes to these estimates or the underlying replacement product costs, or the warranty period expires.