Note 6 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Accrued interest payable		$ 37,415
Accrued Series A convertible preferred stock dividends		1,062,314
Accrued payroll and payroll related expenses	409,889	312,221
Accrued professional fees	69,231	122,711
Accrued clinical studies expenses	34,000	63,350
Other	92,106	30,840
Total	$ 605,226	$ 1,628,851