Note 4 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Accrued payroll and payroll related expenses	$ 277,439	$ 409,889
Accrued professional fees	31,000	69,231
Accrued clinical studies expenses	84,211	34,000
Other accrued expenses	50,787	92,106
Total	$ 443,437	$ 605,226