Note 5 - Operating Lease Right-of-use Asset, Net (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Lease, Expense	$ 150,000	$ 150,000
Operating Lease, Payments	$ 162,000	$ 158,000
Operating Lease, Weighted Average Remaining Lease Term (Year)	273 days
Operating Lease, Weighted Average Discount Rate, Percent	12.05%