angularjs - PHP $_POST Not Returning Values

In PHP I have a form that submits data to a PHP script. The PHP script prints the values, using:

  $raw_post = file_get_contents('php://input');
  print_r($raw_post);
  print_r($_POST);
  print_r($_REQUEST);

All of these come back empty/null arrays EXCEPT $raw_post (aka, php://input).

Chrome's Developer Tools also show that the values have been submitted through the payload as a POST request and it is a status of 200 OK, yet PHP does not set them to the $_POST array at all.

Results in the $raw_post:

{"company_name":"test","primary_contact":"test","address":"test","function":"test","phone":"test","fax":"test","url":"test"}

Results in $_POST:

Array
(
)

Results in $_REQUEST:

Array
(
)

I am unable to find a solution to this issue ... could anybody help here?

The form is submitted from AngularJS to a PHP script.

New code (url-encoded):

app.factory('Companies', function($resource) {
    return $resource('/api.php/companies/:id', {id:''}, {

        'query': {method: 'GET', isArray: true},
        'view': {method: 'GET', isArray: true},
        'save': {
            method: 'POST',
            isArray: true,
            headers: {'Content-Type': 'application/x-www-form-urlencoded'}},
    });
});