Note 10 - Stockholders' Equity (Details Textual) - USD ($)		12 Months Ended
	May 22, 2019	Dec. 31, 2019	Dec. 31, 2018
Common Stock, Shares Authorized		25,000,000	25,000,000
Common Stock, Par or Stated Value Per Share		$ 0.001	$ 0.001
Common Stock, Shares, Issued, Total		20,547,668	18,228,887
Preferred Stock, Shares Authorized		2,500,000	2,500,000
Preferred Stock, Shares Issued, Total		0	0
Proceeds from Issuance of Common Stock		$ 14,650,039	$ 6,029,677
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		25,000	70,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		$ 0
Common Stock, Shares, Outstanding, Ending Balance		20,547,668	18,228,887
Preferred Stock, Shares Outstanding, Ending Balance		0	0
The 2011 Stock Options Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance		25,000
Stock Awards Other than Options [Member]
Share-based Payment Arrangement, Expense		$ 85,443	$ 100,667
Share-based Payment Arrangement, Option [Member] | The 2011 Stock Options Plan [Member]
Share-based Payment Arrangement, Expense		$ 0	$ 15,767
Public Offering [Member]
Stock Issued During Period, Shares, New Issues	2,215,862
Share Price	$ 7.25
Proceeds from Issuance of Common Stock	$ 14,516,839
Payments of Stock Issuance Costs	$ 1,548,161
Convertible Preferred Stock [Member]
Preferred Stock, Shares Issued, Total		0	0
Preferred Stock, Shares Outstanding, Ending Balance		0	0