Tax implications of moving to a different state to work remotely

I presently work and live in California, and will be moving my residence to Pennsylvania permanently (PA house and driver's license, and no property owned in CA).  My boss wants me to work remotely from PA.  Let's say that it happens on June 30 so that I spend 6 months in CA and 6 months in PA.  What are the implications of my company continuing to withhold as if I live in CA for the whole year?  Will everything be reconciled when I do my taxes? i.e. I will claim 6 months in CA, and get a big refund, and claim 6 months in PA and owe a lot to PA?  Do I have to worry about CA taxing me for the whole year?  Do I have to worry about PA penalties for underwithholding? 

 

This seems like a bad idea to me, and I want my company to switch my withholding to PA when I move.  I want to understand the above implications, so I can educate my boss on why it is a bad idea not to switch the withholdings to PA.