Note 3 - Certificates of Deposit (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Certificates Of Deposit Maximum Value Per Deposit	$ 250,000
Certificates of Deposit, at Carrying Value, Current and Noncurrent	4,095,000	$ 3,612,890
Payments to Acquire Investments, Total	244,825
Certificates of Deposit [Member]
Payments to Acquire Investments, Total	3,145,000	3,132,890
Proceeds from Sale, Maturity and Collection of Investments, Total	$ 2,662,890	$ 3,610,000