JQuery UI autocomplete with json and ajax

I've seen a lot of questions dealing with passing an array with label and value properties via JSON, but not much about passing strings. My problem is that I cannot seem to get my autocomplete to fill. I ran a dump function and am getting these sample values passed via JSON to the autocomplete:

0: 23456
1: 21111
2: 25698

Here's some code:

$("#auto_id").autocomplete( {
    source: function(request,response) {

        $.ajax ( {
          url: "fill_id.php",
          data: {term: request.term},
          dataType: "json",
          success: function(data) {
            //what goes here?
                 } 
    }) }
   });

Here is fill_id.php:

$param = $_GET['term'];
$options = array();


$db = new SQLite3('database/main.db');
    $results = $db->query("SELECT distinct(turninId) FROM main WHERE turninid LIKE '".$param."%'");


while ($row_id = $results->fetchArray()) {
        $options[] =  $row_id['turninId']; 
    }   
echo json_encode($options);

My autocomplete remains blank. How do I change my JSON array to fill it? Or what do I include in my ajax success function?