Note 8 - Derivatives (Details Textual)		3 Months Ended		6 Months Ended
	Sep. 28, 2018	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	May 08, 2020 USD ($)	Mar. 31, 2020 USD ($)	Mar. 18, 2020 USD ($)	Feb. 05, 2020 USD ($)	Dec. 31, 2019 USD ($)	May 21, 2019 shares	Dec. 31, 2018 USD ($)
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net, Total		$ 50,989	$ (211,939)	$ 50,989	$ (231,347)
Embedded Derivative, Fair Value of Embedded Derivative Liability		4,629,570		4,629,570			$ 2,814,798			$ 50,989
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		(422,081)	$ (211,940)	(394,974)	$ (231,348)
Chief Executive Officer [Member] | Warrants Issued for 2019 Agreement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares											5,753
Bridge Loan Warrants [Member]
Derivative Liability, Total										50,989
Dr. Schwartz Notes Warrants [Member]
Derivative Liability, Total										$ 0		$ 22,644
Promissory Note 2020 Conversion Feature, Tranche One [Member]
Derivative Liability, Total		7,628		7,628
Embedded Derivative, Fair Value of Embedded Derivative Liability									$ 68,796
Promissory Note 2020 Conversion Feature, Tranche Two [Member]
Derivative Liability, Total		8,907		8,907
Embedded Derivative, Fair Value of Embedded Derivative Liability									52,125
Promissory Note 2020 Conversion Feature, Tranche Three [Member]
Derivative Liability, Total		12,210		12,210
Embedded Derivative, Fair Value of Embedded Derivative Liability									$ 20,542
A, B and Agent Warrants [Member]
Derivative Liability, Total		2,830,744		2,830,744				$ 2,669,995
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		51,026		160,749
Warrants and Agent Warrants In Connection With May 2020 Warrant [Member]
Derivative Liability, Total						$ 1,324,184
Embedded Derivative, Fair Value of Embedded Derivative Liability		1,324,184		1,324,184
Warrant Issued in Connection With May 2020 Offering [Member]
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		(460,065)		(460,065)
Agent Warrants Issued In connection With May 2020 Offering [Member]
Derivative Liability, Total		108,527		108,527
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		(26,033)		(26,033)
Warrants and Agent Warrants In Connection With June 2020 Warrant [Member]
Derivative Liability, Total		1,749,721		1,749,721
Embedded Derivative, Fair Value of Embedded Derivative Liability		1,749,721		1,749,721
Warrants In Connection With June 2020 Warrant [Member]
Derivative Liability, Total		1,555,653		1,555,653
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		82,322		82,322
Agent Warrants In Connection With June 2020 Warrant [Member]
Derivative Liability, Total		105,901		105,901
Gain (Loss) on Derivative Instruments, Net, Pretax, Total		$ 5,845		$ 5,845
Bridge Notes [Member] | Convertible Promissory Note [Member]
Debt Instrument, Convertible, Threshold Trading Days	20