Note 13 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Total	$ 17	$ (1,632)	$ (11,672)
Effective Income Tax Rate Reconciliation, Percent, Total	0.03%	(2.40%)	(18.60%)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			$ (6,600)
Income Tax Expense (Benefit), Use of Naked Credit as a Source of Income to Release a Portion of Valuation Allowance			(4,800)
Income Tax Expense (Benefit), Refundable AMT Credit			$ (200)
Deferred Tax Liabilities, Net, Total	$ 34	$ 28
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0	0
Tax Credit Carryforward, Amount	38,800
Liability for Uncertainty in Income Taxes	0	$ 0
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total	770,000
Operating Loss Carryforwards with Expiration Date	660,000
Operating Loss Carryforwards with Indefinite Term	110,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards with Expiration Date	585,800
Operating Loss Carryforwards with Indefinite Term	$ 8,500