Note 3 - Fair Value Measurements 1 (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2020

Dec. 31, 2019

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
Liabilities
Liability classified stock purchase warrants	$	–	$	–	$	84,596	$	84,596
Balance at December 31, 2019	$	–	$	–	$	84,596	$	84,596
Liability classified stock purchase warrants	$	–	$	–	$	44,954	$	44,954
Balance at September 30, 2020	$	–	$	–	$	44,954	$	44,954

	Level 1		Level 2		Level 3		Total
Liabilities
Liability classified stock purchase warrants	$	-	$	-	$	583,734	$	583,734
Balance at December 31, 2018	$	-	$	-	$	583,734	$	583,734
Liability classified stock purchase warrants	$	-	$	-	$	84,596	$	84,596
Balance at December 31, 2019	$	-	$	-	$	84,596	$	84,596

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	Mark-to-market liabilities - stock purchase warrants
Balance at December 31, 2018	$	583,734
Change in fair value - gain		(416,796	)
Balance at September 30, 2019	$	166,938
Balance at December 31, 2019	$	84,596
Change in fair value - gain		(39,642	)
Balance at September 30, 2020	$	44,954

	Mark-to-market liabilities - stock purchase warrants
Balance at December 31, 2018	$	583,734
Change in fair value - gain		(499,138	)
Balance at December 31, 2019	$	84,596

	Mark-to-market liabilities - stock purchase warrants
Balance at December 31, 2017	$	3,852,882
Change in fair value - gain		(3,269,148	)
Balance at December 31, 2018	$	583,734