Thank you @Vanessa A . Your reply seems different from @AmyC. So in your example, if my company headquarter is in KY all the time, and I had business trips in CA about 15 days in total (before and after May), and I am on salary, no special extra income for the activity in CA, I still need to pay CA state tax for the ratio 15/365 of my total income (inside and outside CA)?
