A non-occlusive device is provided that includes a coilable section and a docking section. The coilable section is configured to become coiled into a coil when deployed from a microcatheter within a vascular malformation. The coil is shaped so as to define a sequence of concentric loops. The coil is configured to bridge a neck of the vascular malformation so as to at least partially cover an orifice of the vascular malformation, when in use. The docking section is configured to be deployed from the microcatheter within the vascular malformation. The docking section is configured to, when in use, perform one or more functions selected from the group consisting of: anchoring the device within the vascular malformation, stabilizing the device within the vascular malformation, assisting with positioning of the device within the vascular malformation, and intertwining detachable coils delivered to the vascular malformation. Other embodiments are also described.