Nature of Business and Basis of Preparation (Policies)	9 Months Ended
Nature of Business and Basis of Preparation (Policies)	Dec. 31, 2014
In-Process Research and Development	*In-Process Research and Development* In-process research and development (“IPR&D”) assets are considered to be indefinite-lived until the completion or abandonment of the associated research and development projects. IPR&D represents the fair value assigned to technologies that the Company acquires, which at the time of acquisition have not reached technological feasibility and have no alternative future use. During the period that the assets are considered indefinite-lived, they are tested for impairment on an annual basis, or more frequently if the Company becomes aware of any events occurring or changes in circumstances that indicate that the fair value of the IPR&D assets are less than their carrying amounts. If and when development is complete, which generally occurs when the Company has regulatory approval and is able to commercialize products associated with the IPR&D assets, these assets are then deemed definite-lived and are amortized based on their estimated useful lives at that point in time. If development is terminated or abandoned, the Company may have a full or partial impairment charge related to the IPR&D assets, calculated as the excess of carrying value of the IPR&D assets over fair value.
Contingent Consideration	*Contingent Consideration* As discussed in Note 3. “Acquisitions,” on July 1, 2014, the Company acquired all of the issued shares of ECP Entwicklungsgesellschaft GmbH, a German limited liability company, or ECP, for $13.0 million in cash, with additional potential payments up to a maximum of $15.0 million based on the achievement of certain technical, regulatory and commercial milestones. These milestone payments may be made, at the Company’s option, by a combination of cash or Abiomed common stock. Contingent consideration is recorded as a liability and measured at fair value using a discounted cash flow model utilizing significant unobservable inputs including the probability of achieving each of the potential milestones and an estimated discount rate associated with the risks of the expected cash flows attributable to the various milestones. Significant increases or decreases in any of the probabilities of success or changes in expected timelines for achievement of any of these milestones would result in a significantly higher or lower fair value of these milestones, respectively, and commensurate changes to the associated liability. The fair value of the contingent consideration will be updated at each reporting date by reflecting the changes in fair value reflected in the Company’s condensed consolidated statements of operations.
Recent Accounting Pronouncements	*Recent Accounting Pronouncements* In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers to provide updated guidance on revenue recognition. ASU 2014-09 requires a company to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies may need to use more judgment and make more estimates than under today’s guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 is effective for the Company in the first quarter of fiscal 2018. Early adoption is not permitted. The Company is currently evaluating the impact of adopting ASU 2014-09 on its condensed consolidated financial statements.

Disclosure of accounting policy for completed business combinations (purchase method, acquisition method or combination of entities under common control). This accounting policy may include a general discussion of the purchase method or acquisition method of accounting (including for example, the treatment accorded contingent consideration, the identification of assets and liabilities, the purchase price allocation process, how the fair values of acquired assets and liabilities are determined) and the entity's specific application thereof. An entity that acquires another entity in a leveraged buyout transaction generally discloses the accounting policy followed by the acquiring entity in determining the basis used to value its interest in the acquired entity, and the rationale for that accounting policy.

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