Note 3 - Revenue From Contracts With Customers - Changes in Contract Liabilities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total deferred revenue, beginning of period	$ 860,000	$ 1,195,000	$ 700,000	$ 711,024
Revenue deferred related to sublicense			160,000	495,000
Refund of deferred revenue related to sublicense	(160,000)	(495,000)	(160,000)	(495,000)
Revenue recognized from satisfaction of performance obligations				(11,024)
Total deferred revenue, end of period	$ 700,000	$ 700,000	$ 700,000	$ 700,000