If you need to be a professional corporation or an LLP in California then the idea of setting up in Delaware is a terrible one. If your offices will be in California, you will need to register it here anyway. I can think of at least five other ideas why it is a poor idea.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.