Note 3 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

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	$	-	$	-	$	75,298	$	75,298
Balance at December 31, 2020	$	-	$	-	$	75,298	$	75,298
Liability classified stock purchase warrants	$	-	$	-	$	171,202	$	171,202
Balance at March 31, 2021	$	-	$	-	$	171,202	$	171,202

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

	Mark-to-market liabilities - stock purchase warrants
Balance at December 31, 2019	$	84,596
Change in fair value (gain)		(24,625	)
Balance at March 31, 2020	$	59,971
Balance at December 31, 2020	$	75,298
Change in fair value - loss		95,904
Balance at March 31, 2021	$	171,202