Note 3 - Income Taxes - Provision for (Benefit from) Income Taxes (Details) (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Net operating loss benefit	$ 0	$ 288
State and Local Jurisdiction [Member]
Net operating loss benefit	$ 35	$ 97