SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”), reflect the accounts of Sarepta Therapeutics, Inc. and its wholly-owned subsidiaries. All intercompany transactions between and among its consolidated subsidiaries have been eliminated. Management has determined that the Company operates in one segment: discovering, developing, manufacturing and delivering therapies to patients for the treatment of rare neuromuscular diseases.
Estimates and Uncertainties	Estimates and Uncertainties The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include revenue recognition, inventory, valuation of stock-based awards, research and development expenses and income tax.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist of accounts receivable from customers and cash, cash equivalents and investments held at financial institutions. For the six months ended June 30, 2017, the majority of the Company’s accounts receivable arose from product sales in the U.S. and all customers have standard payment terms which generally require payment within 30 to 45 days. Three individual customers accounted for 55%, 29% and 16% of net product revenues and 58%, 30% and 12% of accounts receivable from product sales, respectively. The Company monitors the financial performance and creditworthiness of its customers so that it can properly assess and respond to changes in the customers’ credit profile. As of June 30, 2017, the Company believes that such customers are of high credit quality. As of June 30, 2017, the Company’s money market funds, commercial paper, corporate bonds and government and governmental agency bonds were concentrated at a single financial institution, which potentially exposes the Company to credit risks. However, the Company does not believe that there is significant risk of non-performance by the financial institution.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2017, the FASB issued ASU No. 2017-09, “Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting”. The amendments in this update provide guidance about which changes to the terms or conditions of a stock-based payment award requires an entity to apply modification accounting in Topic 718. ASU No. 2017-09 will be effective for fiscal years beginning after December 15, 2017, with early adoption permitted. The Company elected to early adopt this guidance as of June 30, 2017 and determined that the adoption of this guidance does not have any impact on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments”. The amendments in this update clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU No. 2016-15 will be effective for fiscal years beginning after December 15, 2017, with early adoption permitted. As of June 30, 2017, the Company has not elected to early adopt this guidance and does not expect the adoption of this guidance to have any impact on its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)”, which supersedes Topic 840, “Leases”. Under the new guidance, a lessee should recognize assets and liabilities that arise from its leases and disclose qualitative and quantitative information about its leasing arrangements. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. ASU No. 2016-02 will be effective for fiscal years beginning after December 15, 2018, with early adoption permitted. The adoption of this standard is expected to have an impact on the amount of the Company’s assets and liabilities. As of June 30, 2017, the Company has not elected to early adopt this guidance or determined the effect that the adoption of this guidance will have on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)”. This ASU supersedes the revenue recognition requirements in Accounting Standards Codification Topic 605, “Revenue Recognition”. Under the new guidance, a company is required to recognize revenue when it transfers goods or renders services to customers at an amount that it expects to be entitled to in exchange for these goods or services. The new standard allows for either a full retrospective with or without practical expedients or a retrospective with a cumulative catch upon adoption transition method. This guidance was originally intended to be effective for the fiscal years beginning after December 15, 2016, with early adoption not permitted. In August 2015, the FASB issued ASU No. 2015-14, “Deferral of the Effective Date”, which states that the mandatory effective date of this new revenue standard will be delayed by one year, with early adoption only permitted in fiscal year 2017. During the second quarter of 2016, the FASB issued three amendments to the new revenue standard to address some application questions: ASU No. 2016-10, “Identifying Performance Obligations and Licensing”, ASU No. 2016-11, “Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09”, and ASU No. 2016-12, “Narrow-Scope Improvements and Practical Expedients”. In December 2016, the FASB issued ASU No. 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers”, which amends certain narrow aspects of the guidance issued in ASU 2014-09 including guidance related to the disclosure of remaining performance obligations and prior-period performance obligations, as well as other amendments to the guidance on loan guarantee fees, contract costs, refund liabilities, advertising costs and the clarification of certain examples. These three amendments will be effective upon adoption of Topic 606. The Company is currently reviewing the new standards as compared to its current accounting policies with respect to its product revenues and a review of its customer contracts is also in process. During the second half of 2017, the Company plans to finalize its review of product revenues as well as revenue streams from its MAPs to determine the impact that this standard may have on its results of operations, financial position and disclosures. As of June 30, 2017, the Company has not yet determined which adoption method it will utilize or the effect that the adoption of this guidance will have on its consolidated financial statements.
Reclassification	Reclassification The Company has revised the presentation as well as the caption of certain cash flows from financing activities in the unaudited condensed consolidated statements of cash flows to conform to the current period presentation. “Proceeds from exercise of options, purchase of stock under the Employee Stock Purchase Program and sales of common stock” of $39.7 million for the six months ended June 30, 2016 has been reclassified to “Proceeds from sales of common stock, net of offering costs” of $37.5 million and “Proceeds from exercise of options and purchase of stock under the Employee Stock Purchase Program” of $2.2 million and presented separately within cash flows from financing activities in the unaudited condensed consolidated statements of cash flows. This revision had no impact on net cash provided by financing activities or change in cash and cash equivalents. Additionally, the Company has revised the presentation as well as the captions of certain accrued expenses in Note 10, Accrued Expenses to the unaudited condensed consolidated financial statements to conform to the current period presentation. “Product revenue related reserves” of $0.3 million as of December 31, 2016 has been reclassified from “Other” of $3.6 million and presented separately in the accrued expenses table. The reclassification had no impact on total current liabilities or total liabilities.