| Significant Accounting Policies | Significant Accounting Policies Basis of Presentation and Consolidation The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The consolidated financial statements include the accounts of Aerie and its wholly-owned subsidiaries. All intercompany accounts, transactions and profits have been eliminated in consolidation. Certain reclassifications have been made to prior year amounts to conform to the current year presentation. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of income and expenses during the reporting periods. Significant items subject to such estimates and assumptions include revenue recognition, acquisitions, stock-based compensation and fair value measurements. Actual results could differ from the Company’s estimates. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business as one operating segment. Concentration of Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash, cash equivalents and investments. The Company’s cash and cash equivalents, which include short-term highly liquid investments with original maturities of three months or less, are held at several financial institutions. The Company’s investment policy permits investments in U.S. federal government and federal agency securities, corporate bonds or commercial paper, money market instruments, and certain qualifying money market mutual funds, and places restrictions on credit ratings, maturities, and concentration by type and issuer. The Company is exposed to credit risk in the event of a default by the financial institutions holding its cash, cash equivalents and investments to the extent recorded on the consolidated balance sheet. The Company relies on its third-party manufacturers to produce the active pharmaceutical ingredient (“API”) and final drug product for Rhopressa ® and Rocklatan ® and may rely on third-party manufacturers for its current and future product candidates. In addition to the current contract manufacturers, the Company obtained FDA approval for an additional Rhopressa ® drug product contract manufacturer in the first quarter of 2019, which began to supply commercial product in the second quarter of 2019. Further, the Company has obtained FDA approval for an additional API contract manufacturer, which began to supply commercial API in the second quarter of 2019. The Company has also received approval of an additional Rocklatan ® drug product contract manufacturer in January 2020. In addition, the Company has established its own manufacturing plant in Athlone, Ireland, for future commercial production of Rocklatan ® and Rhopressa ® , if approved, and thereafter, potentially Rhokiinsa ® and, if approved, Roclanda ® . In January 2020, the Company received FDA approval to produce Rocklatan ® at the Athlone plant for commercial distribution in the United States. This approval follows a successful pre-approval inspection of the plant and FDA review of the New Drug Application (“NDA”) Prior Approval Supplement (“PAS”), which added the Athlone manufacturing plant as a drug product manufacturer for Rocklatan ® . The Company expects FDA approval to produce Rhopressa ® at the Athlone plant by the end of 2020. The Company expects to continue to use product sourced from the contract manufacturers in addition to the manufacturing plant in Athlone, Ireland. Revenue Recognition The Company accounts for its revenue transactions under FASB ASC Topic 606, Revenue from Contracts with Customers . In accordance with ASC Topic 606, the Company recognizes revenues when its customers obtain control of its product for an amount that reflects the consideration it expects to receive from its customers in exchange for that product. To determine revenue recognition for contracts that are determined to be in scope of ASC Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies the performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. Once the contract is determined to be within the scope of ASC Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when such performance obligation is satisfied. Aerie’s customers include a limited number of national and select regional wholesalers (the “distributors”). These distributors subsequently resell the product, primarily to retail pharmacies that dispense the product to patients. Net product revenue is typically recognized when distributors obtain control of the Company’s products, which occurs at a point in time, typically upon delivery of product to the distributors. The Company evaluates the creditworthiness of each of its distributors to determine whether it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur. The Company does not assess whether a contract has a significant financing component if the expectation is such that the period between the transfer of the promised goods to the customer and the receipt of payment will be less than one year. Standard credit terms do not exceed 75 days. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that would have been recognized is one year or less or the amount is immaterial. Shipping and handling costs related to the Company’s product sales are included in selling, general and administrative expenses. The Company’s net product revenues through December 31, 2019 were generated through sales of Rhopressa ® , which was commercially launched in the United States at the end of April 2018, and sales of Rocklatan ® , which was commercially launched in the United States in May 2019. Product revenue is recorded net of trade discounts, allowances, commercial and government rebates, co-pay program coupons, chargebacks, U.S. government funding requirements for the coverage gap (commonly called the “donut hole”) portion of the Medicare Part D program and estimated returns and other incentives. These reserves are classified as either reductions of accounts receivable or as current liabilities. The estimates of reserves established for variable consideration reflect current contractual and statutory requirements, known market events and trends, industry data, forecasted customer mix and lagged claims. The transaction price, which includes variable consideration reflecting the impact of discounts and allowances, may be subject to constraint and is included in the net product revenues only to the extent that it is probable that a significant reversal of the amount of the cumulative revenues recognized will not occur in a future period. Actual amounts may ultimately differ from these estimates. If actual results vary, estimates may be adjusted in the period such change in estimate becomes known, which could have an impact on earnings in the period of adjustment. See Note 3 for additional information. Cash Equivalents The Company’s cash and cash equivalents are held at several financial institutions. The Company considers money market accounts and short-term highly liquid investments with original maturities of three months or less to be cash equivalents. Inventories Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first-out (“FIFO”) method. The Company analyzes its inventory levels at least quarterly and writes down inventory that is expected to expire prior to being sold, inventory in excess of expected sales requirements and inventory that fails to meet commercial sale specifications, with a corresponding charge to cost of goods sold. The determination of whether inventory costs will be realizable requires estimates by management of future expected inventory requirements based on sales forecasts. If actual net realizable value is less than the estimated amount or if actual market conditions are less favorable than the Company’s projections, additional inventory write-downs may be required. Charges for inventory write-downs are not reversed if it is later determined that the product is saleable. Prior to the date the Company obtains regulatory approval for its product candidates or its manufacturing facilities such as its manufacturing plant in Athlone, Ireland, manufacturing costs related to commercial production are expensed as pre-approval commercial manufacturing expense on the consolidated statements of operations and comprehensive loss. Once regulatory approval is obtained, the Company capitalizes such costs as inventory on the consolidated balance sheets. Property, Plant and Equipment, Net Property, plant and equipment is recorded at historical cost. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. Construction-in-progress reflects amounts incurred for property, plant or equipment construction or improvements that have not been yet placed in service and are not depreciated or amortized, which primarily relates to the completion of the build-out of the Company’s manufacturing plant in Ireland. Repairs and maintenance are expensed when incurred. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are removed from the accounts, and any resulting gain or loss is included in the determination of net loss. Estimated useful lives by major asset category are as follows: Manufacturing equipment 10 years Laboratory equipment 7 years Furniture and fixtures 5 years Software, computer and other equipment 3 years Leasehold improvements Lower of estimated useful life or term of lease Leases The Company determines if an arrangement is a lease at inception. For each lease, the lease term is determined at the commencement date and includes renewal options and termination options when it is reasonably certain that the Company will exercise that option. Operating leases with lease terms greater than one year are included in operating lease right-of-use (“ROU”) assets and current and long-term operating lease liabilities in the Company’s consolidated balance sheets. Operating lease ROU assets represent the right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term using an estimated rate of interest the Company would have to pay to borrow equivalent funds on a collateralized basis at the lease commencement date. The operating lease ROU assets are based on the liability adjusted for any prepaid or deferred rent and lease incentives. The incremental borrowing rate was utilized to discount lease payments over the expected term given that the Company’s operating leases do not provide an implicit rate. The Company estimates the incremental borrowing rate to reflect the profile of secured borrowing over the expected term of the leases based on the information available at the later of the date of adoption or the lease commencement date. Rent expense for the operating lease is recognized on a straight-line basis over the lease term. The Company’s lease agreements have lease and non-lease components, which are generally accounted for as a single lease component. Non-lease components include lease operating expenses, which are variable costs under the Company’s current leases. For vehicle leases, the Company accounts for the lease and non-lease components as a single lease component and applies a portfolio approach to effectively account for the operating lease ROU assets and liabilities. Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by a comparison of the carrying amount of an asset or asset group to estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the asset. For the years ended December 31, 2019 , 2018 and 2017 , no such impairment losses have been recorded by the Company. Acquisitions The Company evaluates acquisitions to determine whether the acquisition is a business combination or an acquisition of assets under ASC Topic 805. Business combinations are accounted for using the acquisition method of accounting, whereby assets acquired and liabilities assumed are recorded as of the acquisition date at their respective fair values and excess of the fair value of the consideration transferred over the fair value of the net assets acquired is recorded as goodwill. In an asset acquisition that does not constitute a business, no goodwill is recognized, and the net assets acquired are generally recorded at cost. Significant judgment is required in estimating the fair value of intangible assets and in a determination of whether an acquisition is a business combination or an acquisition of assets. The fair value estimates are based on available historical information and on future expectations and assumptions deemed reasonable by management, but are inherently uncertain. The consolidated financial statements as of and for the years ended December 31, 2019 and December 31, 2017 include the impact of the acquisition of assets from Avizorex and Envisia, respectively (see Note 1 for additional information). Research and Development Costs Research and development costs are charged to expense as incurred and include, but are not limited to: • employee-related expenses including salaries, benefits, travel and stock-based compensation expense for research and development personnel; • expenses incurred under agreements with contract research organizations (“CROs”), contract manufacturing organizations and service providers that assist in conducting clinical and preclinical studies; • costs associated with any collaboration arrangements, licenses or acquisitions of preclinical molecules, product candidates or technologies; • costs associated with preclinical activities and development activities; • costs associated with regulatory operations; and • depreciation expense for assets used in research and development activities. Costs for certain development activities, such as clinical studies, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the patterns of costs incurred, and are reflected in the consolidated financial statements as prepaid expenses or accrued expenses as deemed appropriate. No material adjustments to these estimates have been recorded in these consolidated financial statements. Research and development costs also include the cost of IPR&D projects acquired as part of an asset acquisition that have no alternative future use. Milestone payments due to third parties in connection with research and development activities prior to regulatory approval are expensed as incurred, while milestone payments due to third parties upon, or subsequent to, regulatory approval are capitalized and amortized over the estimate useful life. Stock-Based Compensation Stock-based compensation for awards granted to employees and non-employees is measured at grant date, based on the estimated fair value of the award. The Company estimates the fair value of options to purchase common stock and stock appreciation rights (“SARs”) using a Black-Scholes option pricing model. The Black-Scholes option pricing model utilizes assumptions including expected term, volatility, a risk-free interest rate and an expected dividend yield. The Company utilized the guidance set forth in the Securities and Exchange Commission (“SEC”) Staff Accounting Bulletin 107, Share-Based Payment (“SAB 107”), to determine the expected term of options, as it does not have sufficient historical exercise and post-vesting termination data to provide a reasonable basis upon which to estimate the expected term of stock options granted to employees. The simplified method utilizes the midpoint between the vesting date and the maximum contractual expiration date as the expected term. Volatility is based on the historical volatility of the Company as well as several public entities that are similar to the Company. The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term. The Company uses an expected dividend yield of zero as it does not expect to pay cash dividends for the foreseeable future. Upon issuance and at each reporting period, the fair value of each SARs award is estimated using the Black-Scholes option pricing model and is marked to market through stock-based compensation expense. SARs are liability-based awards as they may only be settled in cash. The fair value of restricted stock awards (“RSAs”) and restricted stock units (“RSUs”), including restricted stock awards with non-market performance and service conditions (“PSAs”) are determined based on the fair value of Aerie’s common stock on the date of grant. Compensation expense related to RSAs and RSUs are recognized ratably over the vesting period. As the PSAs have multiple performance conditions, compensation expense is recognized for each vesting tranche over the respective requisite service period of each tranche if and when the Company’s management deems it probable that the performance conditions will be satisfied. Stock-based compensation related to stock options, RSAs, RSUs and PSAs is expensed on a straight-line basis over the relevant vesting period, although the Company may recognize a cumulative true-up adjustment related to PSAs once a condition becomes probable of being satisfied if the related service period had commenced in a prior period. All stock-based compensation expense is recorded between selling, general and administrative, pre-approval commercial manufacturing and research and development costs in the consolidated statements of operations and comprehensive loss based upon the underlying employees’ roles within the Company. The Company accounts for forfeitures as they occur. Investments The Company determines the appropriate classification of its investments in debt and equity securities at the time of purchase. The Company’s investments are classified as available-for-sale in accordance with ASC Topic 320, Investments—Debt and Equity Securities . The Company classifies investments available to fund current operations as current assets on its consolidated balance sheets. Investments are classified as long-term assets on the consolidated balance sheets if (i) the Company has the intent and ability to hold the investments for a period of at least one year and (ii) the contractual maturity date of the investments is greater than one year. Available-for-sale investments in debt securities are recorded at fair value, with unrealized gains or losses included in comprehensive loss on the consolidated statements of operations and comprehensive loss and in accumulated other comprehensive loss on the consolidated balance sheets. Realized gains and losses, interest income earned on the Company’s cash, cash equivalents and investments, and amortization or accretion of discounts and premiums on investments are included within other income (expense), net. Interest income was $3.0 million , $3.4 million and $1.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Realized gains and losses are determined using the specific identification method and are included as a component of other income (expense), net. Realized gains or losses were immaterial for the years ended December 31, 2019 , 2018 and 2017 . The Company reviews investments in debt securities for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. The Company did not recognize any impairments on its investments during the years ended December 31, 2019 , 2018 or 2017 . Fair Value Measurements The Company records certain financial assets and liabilities at fair value in accordance with the provisions of ASC Topic 820, Fair Value Measurements and Disclosures . As defined in the guidance, fair value, defined as an exit price, represents the amount that would be received to sell an asset or pay to transfer a liability in an orderly transaction between market participants. As a result, fair value is a market-based approach that should be determined based on assumptions that market participants would use in pricing an asset or a liability. As a basis for considering these assumptions, the guidance defines a three-tier value hierarchy that prioritizes the inputs used in the valuation methodologies in measuring fair value. • Level 1—Unadjusted quoted prices in active, accessible markets for identical assets or liabilities. • Level 2—Other inputs that are directly or indirectly observable in the marketplace. • Level 3—Unobservable inputs that are supported by little or no market activity. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The Company’s cash equivalents are carried at fair value according to the fair value hierarchy described above. The Company’s investments were valued utilizing Level 2 inputs and the Convertible Notes were valued utilizing Level 2 inputs as of December 31, 2019. There were no transfers between the different levels of the fair value hierarchy in 2019 or in 2018 . Convertible Notes Transaction The Company separately accounts for the liability and equity components of convertible notes transactions that can be settled in cash by allocating the proceeds from issuance between the liability component and the embedded conversion option in accordance with accounting for convertible debt instruments that may be settled in cash (including partial cash settlement) upon conversion. The value of the equity component is calculated by first measuring the fair value of the liability component, using the interest rate of a similar liability that does not have a conversion feature, as of the issuance date. The difference between the proceeds from the convertible debt issuance and the amount measured as the liability component is recorded as the equity component with a corresponding discount recorded on the debt. The Company recognizes amortization of the resulting discount using the effective interest method as interest expense on the consolidated statements of operations and comprehensive loss. The equity component is not remeasured as long as it continues to meet the conditions for equity classification. The Company allocates issuance costs incurred to the liability and equity components. Issuance costs attributable to the liability component are amortized to expense over the respective term of the convertible notes, and issuance costs attributable to the equity component are netted with the respective equity component in additional paid-in capital. In September 2019, the Company bought capped call options from financial institutions to minimize the impact of potential dilution of Aerie common stock upon conversion of the Convertible Notes. The capped call options meet the definition of a derivative in accordance with ASC 815, Derivatives and Hedging (“ASC 815”), however, qualify for derivative scope exception under ASC 815 for instruments indexed to a company’s own stock. Accordingly, the premiums for the capped call options were recorded as additional paid-in capital on the Company’s consolidated balance sheet as the options are settleable in Aerie common stock at the election of the Company. See Note 10 for additional information. Comprehensive Loss Comprehensive loss is comprised of net loss and other comprehensive loss. Other comprehensive loss includes changes in stockholders’ equity that are excluded from net income (loss), specifically changes in unrealized gains and losses on the Company’s available-for-sale securities. Income Taxes Deferred tax assets or liabilities are recorded for temporary differences between financial statement and tax basis of assets and liabilities, using enacted rates in effect for the year in which the differences are expected to reverse. A valuation allowance is recorded if it is more likely than not that a deferred tax asset will not be realized. The Company has provided a full valuation allowance on its deferred tax assets that consist of federal and state net operating losses (“NOLs”), stock-based compensation and tax credits as of December 31, 2019 and 2018 (Note 11 ). The Company reduced its valuation allowance during the year ended December 31, 2017 for federal alternative minimum tax (“AMT”) credit carryforwards that became fully refundable under the Tax Act (defined herein). See Note 11 for additional information. As of December 31, 2019 and 2018 , the Company had no uncertain tax positions. The Company recognizes the impact of an uncertain tax position in the consolidated financial statements only if it is more likely than not that the tax position will be sustained upon examination by the taxing authorities. The Company’s policy is to record interest and penalties on uncertain tax positions as income tax expense. The Company did not recognize interest or penalties on uncertain tax positions for the years ended December 31, 2019 , 2018 or 2017 . Adoption of New Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASC Topic 842”). ASC Topic 842 is intended to improve financial reporting of leasing transactions by requiring organizations that lease assets to recognize assets and liabilities for the rights and obligations created by leases that extend more than twelve months on the balance sheet. This accounting update also requires additional disclosures surrounding the amount, timing, and uncertainty of cash flows arising from leases. ASC Topic 842 is effective for financial statements issued for annual and interim periods beginning on January 1, 2019. The Company has elected the optional transition method that provided the option to use the effective date of ASC Topic 842 as the date of initial application on transition. Accordingly, the Company did not adjust comparative periods or make the new required lease disclosures for periods before the effective date of January 1, 2019. There was no cumulative effect adjustment recognized to accumulated deficit upon adoption. As of the date of adoption of the new leasing standards, the Company recognized an operating lease ROU asset of approximately $17.3 million and a corresponding operating lease liability of approximately $17.9 million , which are included in the consolidated balance sheets. The adoption of the new leasing standards did not have a material impact on the consolidated statements of operations and comprehensive loss. The Company elected to utilize the package of practical expedients permitted in ASC Topic 842. Accordingly, the Company accounted for its existing operating leases as operating leases under the new guidance (i) without reassessing the classification of the operating leases in accordance with ASC Topic 842, (ii) without reassessing whether an existing contract contained a lease and (iii) without reassessing initial direct costs. In addition, the Company elected not to allocate the consideration between lease and non-lease components for its operating leases. The Company also reassessed its lease conclusions for its manufacturing plant in Athlone, Ireland, under ASC Topic 842 since construction was still in progress as of the date of adoption. Upon the reassessment, the Company concluded it was the owner of the leased space for accounting purposes under ASC Topic 842 as of the date of adoption and therefore, maintained its previous build-to-suit lease accounting under the transition guidance of ASC Topic 842. In August 2018, the FASB issued Accounting Standards Update (“ASU”) 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 amends ASC 350-40, Internal-Use Software, to include in its scope implementation costs of a cloud computing arrangement that is a service contract. Consequently, the accounting for costs incurred to implement a cloud computing arrangement that is a service arrangement, is aligned with the guidance on capitalizing costs associated with developing or obtaining internal-use software. This ASU is effective for the Company beginning January 1, 2019 and early adoption is permitted. The Company elected to early adopt this standard during the third quarter of 2018, which did not have a material impact on its consolidated financial statements and disclosures. In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”), which expands the scope of ASC Topic 718, Compensation—Stock Compensation to include share-based payments issued to non-employees for goods or services. Consequently, the accounting for share-based payments to non-employees and employees will be substantially aligned. This ASU was effective for the Company beginning January 1, 2019. The adoption of ASU 2018-07 did not have a material impact on the Company’s consolidated financial statements and disclosures. In March 2018, the FASB issued ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 (“SAB 118”) (“ASU 2018-05”), which adds guidance to clarify the treatment of income taxes based on changes enacted in December 2017 in H.R. 1 (referred to herein as the “Tax Act”). ASU 2018-05 incorporates references in ASC Topic 740 to SAB 118, which was issued in December 2017, to address the application of U.S. GAAP in situations when a registrant may not have the necessary information available in reasonable detail to complete the accounting for certain income tax effects. The guidance became effective immediately upon the enactment of the Tax Act in accordance with U.S. GAAP which requires deferred tax assets and liabilities to be revalued during the period in which new tax legislation is enacted. The Company’s final impact assessment on the consolidated financial statements did not materially change from its initial estimates. In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”), which clarifies when changes to the terms or conditions of share-based payment awards must be accounted for as modifications. Under ASU 2017-09, an entity will |
