Drop the Applications YOY into the colour shelf, go to the Edit Colours dialog, set to diverging colours with step of 2. This gives a different colour for postive and negative
Thanks Eric. However this highlights the whole row. Can I highlight only the negative numbers?
Try making it a Highlight Table - It's one of the options in the "Show me" window.
With that it's quite easy to configure colors for different values.
I have worked out how to do it. By just putting all the Measure Values into the colour shelf as @ericmcdonald suggested I can highlight all the negative numbers for the table.