Ember CLI Download Excel [Save As] - blob/binary format Error

I'm making an AJAX POST request from ember-cli to django rest framework in order to enable user to download excel/xls file. However, I'm stuck into formating problem, the file pops up but the content of the xls is not in correct format.

Here's the code I use in the controller:

  Ember.$.ajax({
    type: "POST",
    url: "http://ift.tt/2jvOLBn",
    data: 'ids=' + ids,
    success: function(data) {
      var hiddenElement = document.createElement('a');
      hiddenElement.href = 'data:application/vnd.ms-excel' + encodeURI(data);
      hiddenElement.target = '_blank';
      hiddenElement.download = 'export.xls';
      hiddenElement.click();
    },
  })

Looking for your helpful reply.

Thanks