Symfony2 - Highcharts rendering a blank div

I have just installed the Highcharts Bundle on Symfony 2.7, but I am already facing an issue while trying to reproduce the "Usage Example" from the documentation (cf http://ift.tt/1IPuHeC)

Here is my code :

Controller

public function homepageAction() 
{
    $user = $this->getUser();

    $securityContext = $this->get('security.context');
    $authorization = $securityContext->isGranted('ROLE_REGISTERED_USER');

    if ($authorization) {

        // Charts Test

        $ob = new Highchart();
        $ob->chart->renderTo('piechart');
        $ob->title->text('Browser market shares at a specific website in 2010');
        $ob->plotOptions->pie(array(
            'allowPointSelect' => true,
            'cursor' => 'pointer',
            'dataLabels' => array('enabled' => false),
            'showInLegend' => true
        ));
        $data = array(
            array('Firefox', 45.0),
            array('IE', 26.8),
            array('Chrome', 12.8),
            array('Safari', 8.5),
            array('Opera', 6.2),
            array('Others', 0.7),
        );
        $ob->series(array(array('type' => 'pie', 'name' => 'Browser share', 'data' => $data)));

        return $this->render('MVPBundle:User:homepage.html.twig', array(
            'user' => $user,
            'chart' => $ob,
    ));

    } else {

        $url = $this->generateUrl('user_displayCompanyCreationForm');

        return $this->redirect($url);
    }
}

---

View

<script src='{{ asset('bundles/mvp/js/jquery-2.1.4.js') }}' type="text/javascript"></script>
<script src='{{ asset('bundles/mvp/js/highcharts.js') }}' type="text/javascript"></script>
<script src='{{ asset('bundles/mvp/js/exporting.js') }}' type="text/javascript"></script>

<script type="text/javascript">
    {{ chart(chart) }}
</script>

<div id="linechart" style="min-width: 400px; height: 400px; margin: 0 auto"> </div>

---

After some research, I understood that it could be linked with the import of the JS files, so I made sure the paths to the files were okay, and that Jquery was imported before Highcharts JS files, so I really don't see where the problem comes from... :(

I would appreciate any help ! :)

Cheers,