A drug eluting balloon device is disclosed, comprising a balloon and a sheath disposed around the balloon, the sheath comprising a plurality of drug delivery areas. When the sheath is in a first position, the drug delivery areas are in the form of pockets adapted to contain a therapeutic agent. When the sheath is expanded, the pockets invert into protrusions in order to deliver the therapeutic agent. In an alternative embodiment, the pockets are adapted to be pushed outwardly upon inflation of the balloon. The device may further comprise a fluid or shape memory material to force the pockets outwardly.