How do I send a variable for GET AJAX

$("div#enviarpost").click(function(){
    ididea =$("#ididea").val();
    var datos = new FormData();
    datos.append("ididea",ididea );                                       
        $.ajax({

            url:"views/ajax/ideas.php",
            type: "GET",
            data: datos,
            cache: false,
            contentType: false,
            processData: false,
            success: function(respuesta){
                console.log(respuesta);         
            }
         });
  });

HTML where sent

<form>
      <input id="ididea" type="number" value="'.$item["id_idea"].'"  hidden>
      <a href="ideas" id="enviarpost" class="btn waves-effect white grey-text darken-text-2" >Mostrar Idea</a>
            </form>

and where I do not arrive, I do not arrive

echo $_GET["ididea"];