How render all surfaces on cube

It appears when i render a cube that the back faces do not render.

Am i doing something wrong?

For anyone interested i was using a wave to scale the Cube.

The wave object always outputs a value range of -1.0-1.0

I just needed to put a scale patch after the wave.

Thanks to Matti Niinnimakl on the Facebook Vuo user group for the quick answer.