If you are a California Resident and your gross income or adjusted gross income (AGI) was more than the amount defined by law, you must file a California Income tax return.
If you are a Nonresident and you have both California source income, and income from all other sources that is more than the amount defined by law, you must file a California income tax return.
If you are a Part-Year Resident and your total taxable California income (including income from all sources while you were a California resident and California source income while you were a nonresident) was more than the amount defined by law, you must file a California income tax return.
Source: https://www.ftb.ca.gov/individuals/fileRtn/index.shtml