Note 4 - Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Accrued payroll and payroll related expenses	$ 258,877	$ 409,889
Accrued professional fees	96,124	69,231
Accrued clinical studies expenses	170,755	34,000
Other accrued expenses	77,692	92,106
Total	$ 603,448	$ 605,226