When the America Invents Act (AIA) went into full effect on March 16, 2013, it brought along with it some major changes to American patent law. The most significant change was to switch the American first-to-invent patent-filing system to align with the system used around the world, first-to-file. Along with this major change came a new kind of “post-grant” proceeding called inter partes review, or IPR. Post-grant review proceedings are used to allow parties to challenge the validity of recently granted patents outside of federal court – in the Patent and Trademark Office.