Commitments and Contingencies	3 Months Ended
Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Commitments Leases In February 2017, the Company entered into a lease agreement for 21,603 square feet of office space in Danvers, Massachusetts which expires on July 31, 2022. In December 2017, the Company entered into an amendment to this lease to extend the term through August 31, 2025 and to add an additional 6,607 square feet of space in which rent began on June 1, 2018. In March 2018, the Company entered into an amendment to the lease to add an additional 11,269 square feet of space for which rent began on June 1, 2018 through August 31, 2025. In July 2018, the Company entered into an amendment to lease an additional 23,864 square feet of space from October 1, 2018 through September 30, 2027. With this amendment, the Company will lease 63,343 square feet in total at this location. The Company also has a right of first offer to purchase the property from January 1, 2018 through August 31, 2035, if the lessor decides to sell the building or receives an offer to purchase the building from a third-party buyer. The annual rent expense for the lease is estimated to be $0.9 million. In September 2016, the Company entered into a lease agreement for an office in Berlin, Germany which commenced in May 2017 and expires in May 2024. The annual rent expense for the lease is estimated to be $0.3 million. In October 2016, the Company entered into a lease agreement for an office in Tokyo, Japan which expires in September 2021. The office houses administrative, regulatory, and training personnel in connection with the Company’s commercial launch in Japan. The annual rent expense for the lease is estimated to be $0.9 million. Contingencies From time to time, the Company is involved in legal and administrative proceedings and claims of various types. In some actions, the claimants seek damages, as well as other relief, which, if granted, would require significant expenditures. The Company records a liability in its consolidated financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in liability and the amount of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in its consolidated financial statements. Thoratec Matters Thoratec Corporation, or Thoratec, a subsidiary of Abbott Laboratories, has challenged a number of Company owned patents in Europe in connection with the launch of their HeartMate PHP medical device, or PHP, in Europe. These actions relate to Thoratec’s ability to manufacture and sell their PHP product in Europe. These actions do not relate to the Company’s ability to manufacture or sell its Impella line of devices. In December 2014, Thoratec filed a nullity suit in the German Federal Patent Court against a German “pigtail” patent owned by the Company with a flexible extension feature, and auxiliary pigtail, basket and funnel features. The validity hearing was held in November 2016 and the Federal Patent Court found the patent invalid. The Company is appealing this decision. In August 2015, Thoratec filed a nullity action in the German Federal Patent Court against two Company owned patents covering a “magnetic clutch” feature. These magnetic clutch patents were acquired by the Company in July 2014, in connection with its acquisition of ECP and AIS. The validity hearing for the magnetic clutch patents was held in June 2017. The Company’s patents were upheld in an amended form to focus on the structure and interaction of the magnets in the clutch. The Federal Patent Court found certain unamended claims to be invalid. The Company is appealing the decision with respect to the unamended claims. In September 2015, the Company filed counterclaims in the magnetic clutch action in Germany asserting that the PHP product infringes the two magnetic clutch patents, a European pigtail patent, and the German pigtail patent. The infringement trial has been stayed, pending resolution of the German nullity actions. In February 2017, Thoratec filed an opposition in the European Patent Office, (“EPO”), against a Company owned patent acquired in connection with the acquisition of ECP and AIS relating to a housing structure for an expandable pump. The Company filed an initial response to the opposition in July 2017. Oral proceedings are scheduled for October 26, 2018. In December 2017, Thoratec filed an opposition in the EPO against a Company owned patent acquired in connection with the acquisition of ECP and AIS relating to a pump having a shaft cap with an atraumatic ball. The Company responded to the opposition on May 27, 2018 and is awaiting a preliminary opinion from the EPO Opposition Division. Maquet Matters In December 2015, the Company received a letter from Maquet Cardiovascular LLC, or Maquet, a subsidiary of the Getinge Group, asserting that the Company’s Impella devices infringe certain claims having guidewire, lumen and sensor features, which were in two Maquet patents and one pending patent application in the U.S. and elsewhere, and attached a draft litigation complaint and encouraged the Company to take a license from Maquet. In January 2016, the Company responded to Maquet stating that it believed that the cited claims were invalid and that its Impella devices did not infringe the cited patents. In May 2016, Maquet notified the Company that its pending U.S. patent application had been issued as a U.S. patent, repeated their earlier assertion and encouraged the Company to discuss taking a license from Maquet. The three patents expire September 2020, December 2020 and October 2021. In May 2016, the Company filed suit in U.S. District Court for the District of Massachusetts, (“D. Mass.”), against Maquet seeking a declaratory judgment that the Company’s Impella devices do not infringe Maquet’s cited patent rights. In August 2016, Maquet sent a letter to the Company identifying four new U.S. continuation patent filings with claims that Maquet alleges are infringed by the Company’s Impella devices. Of the four U.S. continuation applications, one issued as a patent on January 17, 2017, one issued as a patent on February 7, 2017, one issued as a patent on March 21, 2017, and one issued as a patent on October 17, 2017. These four issued patents will expire in September 2020. In September 2016, Maquet filed a response to the Company’s suit in D. Mass., including various counterclaims alleging that the Company’s Impella 2.5, Impella CP, Impella 5.0, and Impella RP heart pumps infringe certain claims of the three original issued U.S. patents (“2016 action”). On June 15, 2017, Maquet filed a motion for leave to amend its infringement counterclaims to add the first three additional U.S. continuation patents mentioned above and to file various false advertising, unfair competition claims under state law and under the Lanham Act, and a trademark cancellation in the pending case. Maquet’s amended complaint and counterclaim, like those it originally filed, seek injunctive relief and monetary damages in the form of a reasonable royalty, with three times the amount for alleged willful infringement. The amended complaint admits that Maquet’s current commercially available products do not embody the claims of the asserted patents. On July 21, 2017, the Court granted the motion in part, allowing the three additional continuation patents to be added to the case, but denying addition of the false advertising claims, Lanham Act claims, and the trademark cancellation claims. On April 24 and 25, 2018, the Court conducted a Markman hearing on claim interpretation. The parties are awaiting the judge’s claim construction order. Discovery is ongoing. With regard to the first six Maquet patents mentioned above, in March and April 2017, the Company filed requests for inter partes review, (“IPR”), at the U.S. Patent & Trademark Office’s Patent Trial and Appeals Board, (“PTAB’), asserting that the claims are invalid in view of prior art blood pump technology. In September and October 2017, the PTAB denied institution on these IPR requests filed by the Company. In September 2017, the Company filed additional IPRs and in March and April 2018, the PTAB denied institution of these IPR petitions. On November 22, 2017, Maquet filed a second lawsuit in D. Mass alleging that the Company’s Impella 2.5, Impella CP, and Impella 5.0 heart pumps infringe certain claims of the fourth additional U.S. continuation patent mentioned above (the seventh patent overall). In the complaint, Maquet seeks injunctive relief and monetary damages in the form of a reasonable royalty, with three times the amount for alleged willful infringement. In its answer to Abiomed’s counterclaim, Maquet admits that its current commercially available products do not embody the claims of the asserted patents. This second action is in its early stages. The Company is unable to estimate the potential liability with respect to the legal matters noted above. There are numerous factors that make it difficult to meaningfully estimate possible loss or range of loss at this stage of the legal proceedings, including the significant number of legal and factual issues still to be resolved in the Marquet and Thoratec patent disputes.

Note 11. Commitments and Contingencies

Commitments

Leases

In February 2017, the Company entered into a lease agreement for 21,603 square feet of office space in Danvers, Massachusetts which expires on July 31, 2022. In December 2017, the Company entered into an amendment to this lease to extend the term through August 31, 2025 and to add an additional 6,607 square feet of space in which rent began on June 1, 2018. In March 2018, the Company entered into an amendment to the lease to add an additional 11,269 square feet of space for which rent began on June 1, 2018 through August 31, 2025. In July 2018, the Company entered into an amendment to lease an additional 23,864 square feet of space from October 1, 2018 through September 30, 2027. With this amendment, the Company will lease 63,343 square feet in total at this location. The Company also has a right of first offer to purchase the property from January 1, 2018 through August 31, 2035, if the lessor decides to sell the building or receives an offer to purchase the building from a third-party buyer. The annual rent expense for the lease is estimated to be $0.9 million.

In September 2016, the Company entered into a lease agreement for an office in Berlin, Germany which commenced in May 2017 and expires in May 2024. The annual rent expense for the lease is estimated to be $0.3 million.

In October 2016, the Company entered into a lease agreement for an office in Tokyo, Japan which expires in September 2021. The office houses administrative, regulatory, and training personnel in connection with the Company’s commercial launch in Japan. The annual rent expense for the lease is estimated to be $0.9 million.

Contingencies

From time to time, the Company is involved in legal and administrative proceedings and claims of various types. In some actions, the claimants seek damages, as well as other relief, which, if granted, would require significant expenditures. The Company records a liability in its consolidated financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in liability and the amount of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in its consolidated financial statements.

Thoratec Matters

Thoratec Corporation, or Thoratec, a subsidiary of Abbott Laboratories, has challenged a number of Company owned patents in Europe in connection with the launch of their HeartMate PHP medical device, or PHP, in Europe. These actions relate to Thoratec’s ability to manufacture and sell their PHP product in Europe. These actions do not relate to the Company’s ability to manufacture or sell its Impella line of devices.

In December 2014, Thoratec filed a nullity suit in the German Federal Patent Court against a German “pigtail” patent owned by the Company with a flexible extension feature, and auxiliary pigtail, basket and funnel features. The validity hearing was held in November 2016 and the Federal Patent Court found the patent invalid. The Company is appealing this decision.

In August 2015, Thoratec filed a nullity action in the German Federal Patent Court against two Company owned patents covering a “magnetic clutch” feature. These magnetic clutch patents were acquired by the Company in July 2014, in connection with its acquisition of ECP and AIS. The validity hearing for the magnetic clutch patents was held in June 2017. The Company’s patents were upheld in an amended form to focus on the structure and interaction of the magnets in the clutch. The Federal Patent Court found certain unamended claims to be invalid. The Company is appealing the decision with respect to the unamended claims.

In September 2015, the Company filed counterclaims in the magnetic clutch action in Germany asserting that the PHP product infringes the two magnetic clutch patents, a European pigtail patent, and the German pigtail patent. The infringement trial has been stayed, pending resolution of the German nullity actions.

In February 2017, Thoratec filed an opposition in the European Patent Office, (“EPO”), against a Company owned patent acquired in connection with the acquisition of ECP and AIS relating to a housing structure for an expandable pump. The Company filed an initial response to the opposition in July 2017. Oral proceedings are scheduled for October 26, 2018. In December 2017, Thoratec filed an opposition in the EPO against a Company owned patent acquired in connection with the acquisition of ECP and AIS relating to a pump having a shaft cap with an atraumatic ball. The Company responded to the opposition on May 27, 2018 and is awaiting a preliminary opinion from the EPO Opposition Division.

Maquet Matters

In December 2015, the Company received a letter from Maquet Cardiovascular LLC, or Maquet, a subsidiary of the Getinge Group, asserting that the Company’s Impella devices infringe certain claims having guidewire, lumen and sensor features, which were in two Maquet patents and one pending patent application in the U.S. and elsewhere, and attached a draft litigation complaint and encouraged the Company to take a license from Maquet. In January 2016, the Company responded to Maquet stating that it believed that the cited claims were invalid and that its Impella devices did not infringe the cited patents. In May 2016, Maquet notified the Company that its pending U.S. patent application had been issued as a U.S. patent, repeated their earlier assertion and encouraged the Company to discuss taking a license from Maquet. The three patents expire September 2020, December 2020 and October 2021. In May 2016, the Company filed suit in U.S. District Court for the District of Massachusetts, (“D. Mass.”), against Maquet seeking a declaratory judgment that the Company’s Impella devices do not infringe Maquet’s cited patent rights.

In August 2016, Maquet sent a letter to the Company identifying four new U.S. continuation patent filings with claims that Maquet alleges are infringed by the Company’s Impella devices. Of the four U.S. continuation applications, one issued as a patent on January 17, 2017, one issued as a patent on February 7, 2017, one issued as a patent on March 21, 2017, and one issued as a patent on October 17, 2017. These four issued patents will expire in September 2020.

In September 2016, Maquet filed a response to the Company’s suit in D. Mass., including various counterclaims alleging that the Company’s Impella 2.5, Impella CP, Impella 5.0, and Impella RP heart pumps infringe certain claims of the three original issued U.S. patents (“2016 action”). On June 15, 2017, Maquet filed a motion for leave to amend its infringement counterclaims to add the first three additional U.S. continuation patents mentioned above and to file various false advertising, unfair competition claims under state law and under the Lanham Act, and a trademark cancellation in the pending case. Maquet’s amended complaint and counterclaim, like those it originally filed, seek injunctive relief and monetary damages in the form of a reasonable royalty, with three times the amount for alleged willful infringement. The amended complaint admits that Maquet’s current commercially available products do not embody the claims of the asserted patents. On July 21, 2017, the Court granted the motion in part, allowing the three additional continuation patents to be added to the case, but denying addition of the false advertising claims, Lanham Act claims, and the trademark cancellation claims. On April 24 and 25, 2018, the Court conducted a Markman hearing on claim interpretation. The parties are awaiting the judge’s claim construction order. Discovery is ongoing. With regard to the first six Maquet patents mentioned above, in March and April 2017, the Company filed requests for inter partes review, (“IPR”), at the U.S. Patent & Trademark Office’s Patent Trial and Appeals Board, (“PTAB’), asserting that the claims are invalid in view of prior art blood pump technology. In September and October 2017, the PTAB denied institution on these IPR requests filed by the Company. In September 2017, the Company filed additional IPRs and in March and April 2018, the PTAB denied institution of these IPR petitions.

On November 22, 2017, Maquet filed a second lawsuit in D. Mass alleging that the Company’s Impella 2.5, Impella CP, and Impella 5.0 heart pumps infringe certain claims of the fourth additional U.S. continuation patent mentioned above (the seventh patent overall). In the complaint, Maquet seeks injunctive relief and monetary damages in the form of a reasonable royalty, with three times the amount for alleged willful infringement. In its answer to Abiomed’s counterclaim, Maquet admits that its current commercially available products do not embody the claims of the asserted patents. This second action is in its early stages.

The Company is unable to estimate the potential liability with respect to the legal matters noted above. There are numerous factors that make it difficult to meaningfully estimate possible loss or range of loss at this stage of the legal proceedings, including the significant number of legal and factual issues still to be resolved in the Marquet and Thoratec patent disputes.