Json_decode returning empty value - json object to php array

I have a basic form where I am storing (in the client side) the values in a json format inside a textarea. I then plan to store these values in mysql database. I am using json_decode to place the json object into a regular php array. But when I check print_r($personArray) there is nothing. Therefore everytime I submit the form nothing gets stored in mysql database because the php array is empty. How can I store the values in the text area in mysql database? Here is a LIVE DEMO

if(isset($_POST['submit'])) {
$data = $_POST['data'];
echo $data;
$personArray = json_decode($data, true);
print_r($personArray);


      foreach($personArray as $key => $value){

          $main_role1 = ($value['main1'] == "true") ? 1 : 0;
          $main_role2 = ($value['main2'] == "true") ? 1 : 0;
          $person_fname = $value['firstName'];
          $person_lname = $value['lastName'];
          $person_phone = $value['phone'];

          $query_init2 = "INSERT INTO person (main_role1, main_role2, first_name, last_name, person_phone) VALUES (:main_role1, :main_role2,:person_fname,:person_lname, :person_phone);";
          $query_prep2 = $db_con->prepare($query_init2);
          $insert_result2 = $query_prep2->execute(array(
            "main_role1" => $main_role1,
            "nmain_role2" => $main_role2,
            "person_fname" => $person_fname,
            "person_lname" => $person_lname,
            "person_phone" => $person_phone
          ));

        }
      }

HTML

<textarea name="data" rows='5' cols='60'>

JSON Object

    [
    {
        "firstName": "Danny",
        "lastName": "LaRusso",
        "ciscoID": "123",
        "academyID": "1",
        "email": "[email protected]",
        "phone": "(555) 121-2121",
        "fax": "(123) 123-4567",
        "contact_role": true,
        "netacadContact": true,
        "netacadStaff": false,
        "netacadSuccess": false,
        "instructor_role": false
    },
    {
        "firstName": "Sensei",
        "lastName": "Miyagi",
        "ciscoID": "456",
        "academyID": "1",
        "email": "[email protected]",
        "phone": "(555) 444-2222",
        "fax": "(123) 123-4567",
        "contact_role": false,
        "netacadContact": false,
        "netacadStaff": false,
        "netacadSuccess": false,
        "instructor_role": true
    }
]