Treatment of an aneurysm or other vascular defect can be facilitated or enhanced by an implant delivered with a thermally activated detachment system. A delivery system can include an implant with a proximal portion that defines a port. A pusher device can include arms extending distally from a junction of the pusher device and through the port, with distal sections of the arms disposed within the implant. The arms can, at a certain temperature, transition from engagement with the implant to a shape that facilitates release of the implant. Additionally or alternatively, a coil can engage an outer surface of the implant at the proximal portion and transition to a shape that facilitates release of the implant.