Ember + local am charts integration not defined

I am struggling with adding amcharts library to my ember app. I can't user bower because I have a commercial version of the am-charts.

The chart is not displayed and the error I am getting in the terminal is:

components/quality-chart.js: line 24, col 17, 'AmCharts' is not defined.

What's interesting the chrome's javascript console doesn't report any errors.

According to the Ember's guide I should:

1. Add my javascript to vendor's file. I did. It's there.

2. Import the library using app.import in the ember-cli:

   var EmberApp = require('ember-cli/lib/broccoli/ember-app');
    module.exports = function(defaults) {
     var app = new EmberApp(defaults, {
       'ember-bootstrap': {
                  'importBootstrapTheme': true
              }
       // Add options here
     });
   
     app.import('vendor/charts/amcharts/amcharts.js');
     app.import('vendor/charts/amcharts/serial.js');
   
     return app.toTree();
   };
   
   

3. In my component I am trying to add chart in the didInsertElement callback:

   import Ember from 'ember';
   
   export default Ember.Component.extend({
     chartData: function(){
        return generateChartData();
      }.property(),
   didInsertElement() {
   this._super(...arguments);
   var chartData = this.get('chartData');
   var amExport = {
     top:80,
     right:20,
     imageFileName:'sample-graph',
     buttonTitle: 'Save Chart'
   };
   
   this.set('chartData', chartData);
   
   var chart = AmCharts.makeChart("chartdiv", {
   
   

4. Template

 
 <div class="chartDiv" style="width:500px; height:500px"></div>