Note 7 - Income Taxes - Changes in Valuation Allowance (Details) - USD ($) $ in Thousands |
12 Months Ended | |
---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
Valuation allowance at the Beginning of Period | ||
Income tax expense | (11,435) | |
Release of valuation allowance | ||
Valuation allowance at the End of Period | $ (11,435) |