Note 4 - Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 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		6,758,897		6,676,112
Vested Series A warrants		--		40,441
Unvested Series A warrants(1)		--		69,853
Warrants – other		653,248		1,006,190
Stock options		386,461		893,349
Total		7,798,606		8,685,945