Note 12 - Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Tax at federal statutory rate	$ (2,500)	$ (2,651)
State, net of federal benefit	(190)	0
Research and development credit	(291)	(279)
Share-based compensation	101	264
Other	0	2
Change in valuation allowance	2,880	2,664
Total provision for income taxes	$ 0	$ 0

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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