Note 3 - Fair Value Measurements - Activity for Items Measured at Fair Value on a Recurring Basis 1 (Details) - Stock Purchase Warrants [Member] - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Balance	$ 84,596	$ 583,734	$ 583,734	$ 3,852,882
Change in fair value - gain	(39,642)	(416,796)	(499,138)	(3,269,148)
Balance	$ 44,954	$ 166,938	$ 84,596	$ 583,734

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant