I would suggest not doing this check here at all.  A more efficient and convenient solution is to write the show component in the vertex data as `(show && width > 0.0)`.  For example, see `writeOriginAndShow` in [BillboardCollection.js](https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/BillboardCollection.js).

As for widths less than `1.0`, I would have to try it.