TurboTax will prompt you to file a state return if you indicated you moved into or out of a state during the year. The program may also prompt you to file a state return if you enter the state abbreviation on any items of income (like a W-2 or 1099). If you are certain that you do not need to file a state return, and in your case it appears that you do not need to file the Idaho return, you can simply delete the state from your return. If you have already paid for the state you will not be able to delete it but you do not need to actually file it. When going through the filing stages do not select the Idaho return to file.
