After initialization, you need to set up the widthchart setting . After initialization, Highcharts only adapts to the resize event (try, if you resize the window, it will change the width), so you may need to trigger a resize event.
Here is jsFiddle (ab) using the resize event: http://jsfiddle.net/b9DMn/1/
Highcharts automatically gets the width of its container when creating its chart, but if you set a breakpoint, you will see that the table cells are still divided evenly at this point in time. In fact, this is a chart that causes the table to grow the correct cell. If you can fix the width of the cell, this will probably help too.
jsFiddle, , : http://jsfiddle.net/b9DMn/2/