BASIS OF PRESENTATION (Policies)

3 Months Ended

Mar. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

General –The accompanying unaudited condensed consolidated financial statements have been prepared by athenahealth, Inc. (the “Company,” “we,” “us,” or “our”) in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. The year-end condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by GAAP for complete financial statements. In the opinion of the Company’s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments (consisting of items of a normal and recurring nature) necessary to fairly present the financial position as of March 31, 2016, the results of operations for the three months ended March 31, 2016and2015, and cash flows for thethreemonths endedMarch 31, 2016and2015.The results of operations for the three month period ended March 31, 2016 are not necessarily indicative of the results to be expected for the full year. When preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets and liabilities and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates, and such differences could be material.

We consider events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated through the date of issuance of these financial statements.

New Accounting Pronouncements

New Accounting Pronouncements – In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Compensation – Stock Compensation (Topic 718). ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. Under this guidance, a company recognizes all excess tax benefits and tax deficiencies as income tax expense or benefit in the income statement. This change eliminates the notion of the additional paid-in capital pool and reduces the complexity in accounting for excess tax benefits and tax deficiencies. ASU 2016-09 is effective for public companies for annual reporting periods beginning after December 15, 2016, including interim periods within those annual reporting periods; however, early adoption is allowed. We are assessing the impact that adopting this new accounting standard will have on our consolidated financial statements and footnote disclosures.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). ASU 2016-02 most significantly impacts lessee accounting and disclosures. First, this guidance requires lessees to identify arrangements that should be accounted for as leases. Under ASU 2016-02, for lease arrangements exceeding a 12-month term, a right-of-use asset and lease obligation is recorded by the lessee for all leases, whether operating or financing, while the income statement will reflect lease expense for operating leases and amortization/interest expense for financing leases. The balance sheet amount recorded for existing leases at the date of adoption of ASU 2016-02 must be calculated using the applicable incremental borrowing rate at the date of adoption. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. In addition, ASU 2016-02 requires the use of the modified retrospective method, which will require adjustment to all comparative periods presented in the consolidated financial statements. This guidance is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted. We are assessing the impact that adopting this new accounting standard will have on our consolidated financial statements and footnote disclosures.

In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers,which defers the effective date of ASU 2014-09 for all entities by one year. ASU 2014-09 is now effective for public companies for annual reporting periods beginning after December 15, 2017, including interim periods within those reporting periods. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most of the current revenue recognition guidance, including industry-specific guidance. In addition, ASU 2014-09 provides guidance on accounting for certain revenue-related costs including, but not limited to, when to capitalize costs associated with obtaining and fulfilling a contract. ASU 2014-09 provides companies with two implementation methods. Companies can choose to apply the standard retrospectively to each prior reporting period presented (full retrospective application) or retrospectively with the cumulative effect of initially applying the standard as an adjustment to the

opening balance of retained earnings of the annual reporting period that includes the date of initial application (modified retrospective application). We continue to evaluate the expected impact of this new guidance and available adoption methods.