3,
    inputEnabled : false
  },
  plotOptions: {
    series: {
      dataGrouping: { enabled: false }
    },
    area: {
      stacking: 'normal'
    }
  },
  xAxis: {
    type: 'datetime',
    ordinal: false,
    maxZoom: 10000 // three days
  },
  yAxis:[
    {
      min: 0,
      title: { text: 'Number of requests' },
      opposite: false,
      reversedStacks: false
    }, {
      min: 0,
      title: {
        text: 'Active Users',
        style: { color: '#FFA900' }
      },
      opposite: true
   