Note 4 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended		14 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Unrecognized Tax Benefits, Ending Balance	$ 0	$ 0	$ 0
Income Tax Examination, Penalties and Interest Expense, Total	$ 0	$ 0	0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total			291,800
Operating Loss Carryforwards, Subject to Expiration			175,400
Operating Loss Carryforwards, Not Subject to Expiration			116,400
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Subject to Expiration			229,500
Operating Loss Carryforwards, Not Subject to Expiration			$ 14,300