Note 4 - Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	2021		2020
Common stock equivalents of convertible promissory note and accrued interest		6,449,950		5,159,496
Vested Series A warrants		--		40,441
Unvested Series A warrants (1)		--		69,853
Warrants – other		653,248		1,273,461
Stock options		889,636		287,849
Total		7,992,834		6,831,100