Delaware Non-Resident Taxes
You are considered a nonresident if you are legal resident of another state.
If you are a Non-Resident who had gross income from sources in Delaware, you must file a Delaware Tax return.
Forms
Tax Form 200-02 and Delaware Non-Resident Schedule
Reference
Part Year Resident
You are a part-year resident if you moved to Delaware and became a resident during the tax year or you moved out of Delaware and became a resident of another state.
Part-Year Residents may elect to file either a resident or non-resident return which ever is advantageous to taxpayer. Filing as resident may be advantageous, if you had no income from sources in other states, otherwise filing as non-resident may give more tax advantage.
Forms
Depending on whether you are filing as resident or non resident, use Tax Form 200-01 or Tax Form 200-02 and Delaware Non-Resident Schedule.
Reference