Calling REST service after data range was updated by the user

[cyc1ingsir]

I'd like to call a REST service after the user has made changes but not after the initial load.
Therefore, I've added somthing like this into my controller.
However, the function is called after initial load. How could I prevent this?

$scope.$watch('vm.daterange', function(){
            if(vm.daterange.startDate) {
                console.log(vm.daterange.startDate.format('YYYY-MM-DD'), vm.daterange.endDate.format('YYYY-MM-DD'));
            }
        });