Datepicker not appearing in admin

I have a datepicker appearing in a custom post type, however, when I click on the input in the admin screen, the datepicker doesn't load.

	$meta_boxes[] = array(
        'id'       		=> 'events',
        'title'    		=> 'Event details',
        'post_types'    => 'Events',
        'context'  		=> 'normal',
        'priority' 		=> 'high',

		'fields'     => array(
        	array(
				'name'		=> 'Event date',
				'desc'		=> 'Date of event',
				'id'		=> $prefix . 'event_date',
				'type'		=> 'date',
				'timestamp'	=> true,
            ),
		),
	);

I have tried adding

				'js_options' => array(
					'showButtonPanel' => true,
				),

But it hasn't made any difference