Help,to stop this back moving ‘B’ to ‘A’ marker

Here the marker moving from one position 'A' to 'B'

but the marker back to move 'B' to 'A' position ,I want to stop the backward 'B' to 'A' position...

var map, marker;
var startPos = [8.769332, 78.125176];
var speed = 5000; // km/h
var delay = 100;
function animateMarker(marker, coords, km_h)
{
var target = 0;
var km_h = km_h || 50;
coords.push([startPos[0], startPos[1]]);
function goToPoint()
{
var lat = marker.position.lat();
var lng = marker.position.lng();
var step = (km_h * 1000 * delay) / 3600000; // in meters
var dest = new google.maps.LatLng(
coords[target][0], coords[target][1]);
var distance =
google.maps.geometry.spherical.computeDistanceBetween(
dest, marker.position); // in meters
var numStep = distance / step;
var i = 0;
var deltaLat = (coords[target][0] - lat) / numStep;
var deltaLng = (coords[target][1] - lng) / numStep;
function moveMarker()
{
lat += deltaLat;
lng += deltaLng;
i += step;
if (i < distance)
{
marker.setPosition(new google.maps.LatLng(lat, lng));
setTimeout(moveMarker, delay);
}
else
{ marker.setPosition(dest);
target++;
if (target == coords.length){ target = 0; }
setTimeout(goToPoint, delay);
}
}
moveMarker();
}
goToPoint();
}
function initialize()
{
var myOptions = {
zoom: 16,
center: new google.maps.LatLng(8.769332, 78.125176),
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
marker = new google.maps.Marker({
position: new google.maps.LatLng(startPos[0], startPos[1]),
map: map
});
google.maps.event.addListenerOnce(map, 'idle', function()
{
animateMarker(marker, [
// The coordinates of each point you want the marker to go to.
// You don't need to specify the starting position again.
[8.772708, 78.118725],
[8.769332,78.125176],
[8.765796,78.13168]
], speed);
});
}
initialize();