You definitely must file a return for PA, showing yourself as a part-year resident.
Delaware allows part-year residents the option to file either as a full-year resident or as a non-resident. According to the Delaware tax instructions, if your only income during your period of non-residency was from DE, it may be advantageous for you to file as a full-year DE resident. If that's what you decide to do, in TurboTax you would enter your state of residence as DE, and you would enter PA under Other State Income.
See page 2 of this reference: http://revenue.delaware.gov/services/current_pit/TY16_booklet_res.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
