I have retired and had no income in Idaho. Wife worked online remotely tied to her old office in California. Does she (we) need to file an Idaho state return as her W-2 shows only California state taxes?
If you and your wife moved during 2017, you'll have to file a part-year resident return in each of the two states. Idaho can tax the income you and your wife earned after you became Idaho residents, regardless of the source of the income.
This FAQ explains how to file part-year resident returns in TurboTax: https://ttlc.intuit.com/questions/1901227-how-do-i-file-a-part-year-state-return
If your wife still has the same job, she should ask her employer to withhold ID state tax instead of CA state tax. CA can only tax non-residents on income earned from physically working within CA.
If you and your wife moved during 2017, you'll have to file a part-year resident return in each of the two states. Idaho can tax the income you and your wife earned after you became Idaho residents, regardless of the source of the income.
This FAQ explains how to file part-year resident returns in TurboTax: https://ttlc.intuit.com/questions/1901227-how-do-i-file-a-part-year-state-return
If your wife still has the same job, she should ask her employer to withhold ID state tax instead of CA state tax. CA can only tax non-residents on income earned from physically working within CA.