Note 13 - Income Taxes - Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statutory U.S. federal income tax rate	21.00%	21.00%
State and local income taxes, net of federal income tax benefit	(6.60%)	(8.00%)
Permanent differences	1.90%	(2.60%)
Change in valuation allowance	29.20%	(15.90%)
Equity compensation	14.50%	0.00%
Other	0.20%	2.70%
PPP loan forgiveness	(59.60%)	0.00%
Effective income tax rate	0.60%	(2.80%)