text: Mixins.TimeseriesFiller = {};
  Mixins.TimeseriesFiller.prototype = {};
  
  Mixins.TimeseriesFiller.prototype.addFillerData = function(data, endTime) {
    data = data || [];
    data[0] = data[0] || [];
    // add filler data so chart will always have space for full billing cycle
    var latest = _.last(data)[0];
    if (latest < endTime) {
      var fillersRequired = Math.floor((endTime - latest) / (1000 * 60 * 60 * 24));
      for (; fillersRequired-- > 0; ) {
        latest += 1000 * 60 * 60 * 24;
        data.push([latest, null]);
      }
    }
    return data;
  };
  