Note 4 - Income Taxes - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Provision at the U.S. federal statutory rate	21.00%	21.00%
State taxes, net of federal benefit	1.50%	2.70%
Foreign tax rate differential	0.50%
China Enterprise Tax	(2.10%)
Valuation allowance	(13.90%)	(29.20%)
Share based compensation shortfall	(2.00%)
Other true up	(2.70%)	1.60%
Intangible assets impairment and other non-deductibles	1.80%	2.30%
State rate change	(6.50%)
Other	1.00%	1.80%
Income tax (expense) benefit effective rate	(1.40%)	0.20%