State tax filing

What is the difference if I would to commute to CA or not?

 

So I work for a California employer and live in Washington state. However, I commute to my California office 3 days a week. Do I have to pay taxes for all of my income earned through a California employer? Or do I only pay California taxes for the income corresponding to the days I spent in California? 

 

Also, Am I considered a California Resident because 3 work days in CA and 2 work days in WA? Even though I stay at hotels in CA, and my home is in WA.