Mozilla Firefox solution
Add:
display: inline-block;
to the style of your td.
Webkit based browsers (Google Chrome, Safari, …) solution
Add:
display: inline-block;
word-break: break-word;
to the style of your td.
Note:
Mind that, as for now, break-word is not part of the standard specification for webkit; therefore, you might be interested in employing the break-all instead. This alternative value provides a undoubtedly drastic solution; however, it conforms to the standard.
Opera solution
Add:
display: inline-block;
word-break: break-word;
to the style of your td.
The previous paragraph applies to Opera in a similar way.