Datepicker - beforeShowDay Not Working

I'm trying to use beforeShowDay to block days from the calendar. I found this Fiddle code that works. But I can`t figure out why my code doesn't work for me. I get no error-messages. I can see the dates in console which are not -1, the problem is that the calendar doesn't block the dates that are unavailable (the dates that return -1). The user can pick whatever date they want.

This is my html :

<div class="input-group input-append date" id="dateRangePicker">
    <input type="text" id="date" class="form-control" name="date" />
    <span class="input-group-addon add-on"><span class="glyphicon glyphicon-calendar"></span></span>
</div>

and this is my JQuery :

    availableDates = ['04-25-2015','04-27-2015','04-22-2015'];
    $('#date').datepicker({
    dateFormat: 'mm-dd-yy',
    startDate: "04-20-2015",
    endDate: "01-01-2016",
    beforeShowDay: function(d) {
        var dmy = (d.getMonth()+1)
        if(d.getMonth()<9) 
            dmy="0"+dmy; 
        dmy+= "-"; 

        if(d.getDate()<10) dmy+="0"; 
            dmy+=d.getDate() + "-" + d.getFullYear(); 

        console.log(dmy+' : '+($.inArray(dmy, availableDates)));

        if ($.inArray(dmy, availableDates) != -1) {
            return [true, "","Available"]; 
        } else{
             return [false,"","unAvailable"]; 
        }
    },
    todayBtn: "linked",
    autoclose: true,
    todayHighlight: true
    });