function hasEnoughHorizontalRoom(parentChartWidth, positionX) {
            return (parentChartWidth - margin.left - margin.right - chartWidth) - positionX > 0;
        }
Checks if the mouse is over the bounds of the parent chart
@param  {Number}  chartWidth Parent's chart
@param  {Number}  positionX  Mouse position
@return {Boolean}            If the mouse position allows space for the tooltip