Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2018
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Vericel and its wholly-owned subsidiaries, Marrow Donation, LLC, located in San Diego, California, Vericel Denmark ApS, in Kastrup, Demark and Vericel Security Corporation (collectively, the Company). All inter-company transactions and accounts have been eliminated in consolidation. Marrow Donation, LLC and Vericel Denmark ApS ceased operations in 2015.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reported period. Actual results could differ from those estimates.
Inventory	Inventory Inventories are measured at the lower of cost and net realizable value. Cost is calculated based upon standard-cost which approximates costs determined on the first-in, first-out method. The Company periodically reviews its inventories for excess or obsolescence and write-down obsolete or other unmarketable inventory to its estimated net realizable value. If the actual net realizable value is less than that estimated by us, or if it is determined that inventory utilization will further diminish based on estimates of demand, additional inventory write-downs may be required. In all cases, product inventory is carried at the lower of cost or its estimated net realizable value. Amounts written down are charged to cost of sales.
Accounts Receivable	Accounts Receivable Accounts receivable are initially recorded at the contractual amount owed by the customer or based on expected payments from the insurance provider, hospital or patient. Allowances for doubtful accounts are established when the facts and circumstances indicate that a receivable may not be collectible.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are initially measured and recognized at acquisition cost, including any directly attributable cost of preparing the asset for its intended use or, in the case of assets acquired in a business combination, at fair value as at the date of the combination. After initial measurement, property, plant and equipment are carried at cost less accumulated depreciation and impairment. Repair and maintenance costs of property, plant and equipment are expensed as incurred. The depreciable value of property, plant and equipment, net of any residual value, is depreciated on a straight line basis over the useful life of the asset. The useful life of an asset is usually equivalent to its economic life. The useful lives of property, plant and equipment are as follows: •Equipment and computers: 3 to 5 years •Furniture and fixtures: 5 years •Building improvements and leasehold improvements: Shorter of the remaining life of the lease or 10 years The costs of assets retired or otherwise disposed of and the accumulated depreciation thereon are removed from the accounts, with any gain or loss realized upon sale or disposal credited or charged to operations.
Intangible Assets and Other Long Lived Assets	Intangible Assets and Other Long Lived Assets Intangible assets are initially measured at acquisition cost, including any directly attributable costs of preparing the asset for its intended use or, in the case of assets acquired in a business combination at fair value as at the date of the combination. Identifiable intangible assets related to commercial rights are amortized on a straight line basis over their expected useful lives. Amortization of intangible assets is recognized in these financial statements under Cost of product sales. Intangible assets and long-lived assets are assessed for potential impairment when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. An impairment loss would be recognized when an asset’s fair value, determined based on undiscounted cash flows expected to be generated by the asset, is less than its carrying amount. The impairment loss would be measured as the amount by which the asset’s carrying value exceeds its fair value and recognized in these financial statements. Intangible assets are carried at cost less accumulated amortization and impairment.
Research and Development Expense	Research and Development Expense Research and development activities represent a significant part of the Company’s business. These expenditures relate to the development of new products, improvement of existing products, technical support of products and compliance with governmental regulations for the protection of consumers and patients. Research and development expenses are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation The Company’s accounting for stock-based compensation requires it to determine the fair value of common stock issued in the form of stock option awards. The Company uses the value of its common stock at the date of the grant in the calculation of the fair value of its share-based awards. The fair value of stock options held by the employees is determined using a Black-Scholes option valuation method, which is a valuation technique that is acceptable for share-based payment accounting. Key assumptions in determining fair value include volatility, risk-free interest rate, dividend yield and expected term. The assumptions used in calculating the fair value of stock options represent the Company’s best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the stock-based compensation expense could be materially different in the future. In addition, the Company estimates the expected forfeiture rate and only recognize expense for those stock options expected to vest over the service period. The estimated forfeiture rate considers the historical experience of the Company’s stock-based awards. If the actual forfeiture rate is different from the estimate, expense is adjusted accordingly. For certain non-employee consultants, stock option awards continue to vest post-termination. The guidance for non-employee stock compensation accounting for equity-classified awards was updated, and these awards are now subject to fixed grant date fair value principles which eliminates the variable mark-to-market accounting. The options were valued as of the adoption date July 1, 2018. The Company also has an Employee Stock Purchase Plan (ESPP) which is a compensatory plan. Compensation expense is recorded based on the fair value of the purchase options at the grant date, which corresponds to the first day of each purchase period, and is amortized over the purchase period.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is the change in stockholders’ equity during a period arising from any gain or loss unrealized related to
Income Taxes	Income Taxes Deferred tax assets are recognized for deductible temporary differences and tax credit carryforwards and deferred tax liabilities are recognized for taxable temporary differences. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company records uncertain tax positions in the financial statements only if it is more likely than not that the uncertain tax position will be sustained upon examination by the taxing authorities. The Company records interest and penalties related to uncertain tax positions in income tax expense.
Net Loss Per Share Attributable to Common Shareholders	Net Loss Per Share Attributable to Common Shareholders Basic and diluted earnings (loss) per share is calculated using the two-class method. Basic earnings (loss) per share which is based on an earnings allocation formula that determines earnings (loss) per share for the holders of the Company’s common shares and holders of the Series B preferred stock. The Series B preferred stock shares contain participation rights in undistributed earnings, but do not share in the losses of the Company. The accumulated but undeclared dividends on the Series B preferred stock of $7.6 million for the year ended December 31, 2016 is treated as a reduction of earnings attributable to common shareholders. There were no undeclared dividends for the year ended December 31, 2018 or 2017. Diluted earnings (loss) per share includes convertible securities or common equivalent share (stock options and warrants) in addition to the Company's common shares. Common equivalent shares and treasury stock are not included in the diluted per share calculation where the effect of their inclusion would be anti-dilutive.
Financial Instruments	Financial Instruments The Company’s financial instruments include receivables for which the current carrying amounts approximate market value based upon their short-term nature.
Warrants	Warrants Warrants that could be cash settled or have anti-dilution price protection provisions are recorded as liabilities at their estimated fair value at the date of issuance, with subsequent changes in estimated fair value recorded in other income (expense) in our statement of operations in each subsequent period. Warrants that meet the requirements for equity classification are recorded at fair value with no subsequent remeasurement. In general, warrants are measured using the Black-Scholes valuation model. The methodology is based, in part, upon inputs for which there is little or no observable market data, requiring the Company to develop its own assumptions. The assumptions used in calculating the estimated fair value of the warrants represent our best estimates; however, these estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and different assumptions are used, the change in estimated fair value of the warrant liability for those warrants that could be cash settled or have anti-dilution price protection provisions, could be materially different.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Revenue Recognition In May 2014, the Financial Accounting Standards Board (FASB) issued authoritative guidance requiring entities to apply a new model for recognizing revenue from contracts with customers and the reporting of principal versus agent considerations. The guidance superseded the then-applicable revenue recognition guidance and requires entities to evaluate their revenue recognition arrangements using a five step model to determine when a customer obtains control of a transferred good or service. The new revenue standard Accounting Standards Codification 606, Revenue Recognition, (ASC 606), became effective for the Company on January 1, 2018, and was adopted using the modified retrospective method. See note 4 for further discussion. Accounting for Leases The FASB issued guidance to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. In accordance with the updated guidance, lessees are required to recognize the right of use assets and lease liabilities arising from operating leases on the balance sheet. The guidance is effective for annual reporting periods beginning after December 15, 2018, including interim periods within 2019. The Company has evaluated its leasing arrangements under the issued guidance and determined all leases are classified as operating leases and will be recognized as assets and future payments as liabilities on the balance sheet. Based on the Company's evaluation to date, the Company expects that the adoption of the new leasing standards will result in the recognition of material right-to-use assets and liabilities in the Company's consolidated balance sheet. The adoption of the new leasing standards is not expected to have a material impact to the Company's consolidated statements of income. The Company elected to utilize the practical expedients when adopting the standard. Accounting for Non-Employee Share Based Payment Arrangements The FASB issued guidance to expand the scope of stock compensation guidance to include stock compensation granted to nonemployees. Previously, stock compensation granted to nonemployees was subject to vesting date, as opposed to grant date, fair value principles that required companies to re-measure fair value at each reporting period until settlement for equity classified awards. The guidance for non-employee stock compensation accounting for equity-classified awards was updated, and these awards are now subject to fixed grant date fair value principles which eliminates the variable mark-to-market accounting. The non-employee stock awards granted by the Company have a service condition but no performance condition, each of which is measured using the Black-Scholes valuation model. The guidance was adopted early and applied as of July 1, 2018 and reflected in the Company's financial statements. The impact upon adoption was not material and no cumulative adjustment was recorded. Measuring Credit Losses on Financial Instruments The FASB issued updated guidance on measuring credit losses on financial instruments. The guidance removes the thresholds that companies apply to measure credit losses on financial instruments measured at amortized cost, such as loans, receivables, and held-to-maturity debt securities. Prior to the updated guidance, credit losses are recognized when it is probable that the loss has been incurred. The revised guidance removes all recognition thresholds and requires companies to recognize an allowance for credit losses for the difference between the amortized cost basis of a financial instrument and the amount of amortized cost that a company expected to collect over the instrument’s contractual life. The guidance is effective for annual reporting periods beginning after December 15, 2019. The Company is currently in the process of evaluating the impact to its consolidated financial statements.