Note 4 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Accrued payroll and payroll related expenses	$ 542,598	$ 653,899
Accrued professional fees	61,306	31,809
Accrued clinical studies expenses	634,870	1,055,398
Other accrued expenses	16,016	35,364
Total	$ 1,254,790	$ 1,776,470