If the case is metallic, or has metallic threads, no.
The phone has to ba about 1/4" or less from the charger, but most cases are thinner than that, so you're okay. (I always charged through an Otterbox case, and that's pretty thick. Even adding a few sheets of paper between the case and the charger didn't matter.)
The wireless charge stand at Google is pretty expensive, are there any other options?