http://angular-ui.github.io/bootstrap/

<!doctype html>
<html ng-app="ui.bootstrap.demo">
  <head>
    <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.6.1/angular.js"></script>
    <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.6.1/angular-animate.js"></script>
    <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.6.1/angular-sanitize.js"></script>
    <script src="//angular-ui.github.io/bootstrap/ui-bootstrap-tpls-2.5.0.js"></script>
    <script src="example.js"></script>
    <link href="//netdna.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
  </head>
  <body>

<style>
  .full button span {
    background-color: limegreen;
    border-radius: 32px;
    color: black;
  }
  .partially button span {
    background-color: orange;
    border-radius: 32px;
    color: black;
  }
</style>
<div ng-controller="DatepickerPopupDemoCtrl">
  
<input ng-focus="open($event, 'delivery_time_popup')" type="text" class="form-control" uib-datepicker-popup="dd-MMMM-yyyy" show-weeks="false" ng-model="purchase_order.delivery_time" is-open="delivery_time_popup" datepicker-options="dateOptions" required close-text="Close" placeholder="Select Date">

   </div>
  </body>
</html>

angular.module('ui.bootstrap.demo', ['ngAnimate', 'ngSanitize', 'ui.bootstrap']);
angular.module('ui.bootstrap.demo').controller('DatepickerPopupDemoCtrl', function ($scope) {
  
  $scope.open = function ($event, opened) {
        console.log(opened);
        $event.preventDefault();
        $event.stopPropagation();
        $scope[opened] = true;
        
        $scope.delivery_time_popup = true;
    };

    $scope.delivery_time_popup = false;

    $scope.dateOptions = {
        formatYear: 'yy',
        startingDay: 1
    };
});