Note 6 - Preferred Stock (Details Textual) - $ / shares	Dec. 14, 1995	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2011
Preferred Stock, Shares Authorized	3,000,000	2,445,598	2,445,598
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01	$ 0.01
Preferred Stock, Shares Outstanding, Ending Balance		0	0
Series A Preferred Stock [Member]
Preferred Stock, Shares Authorized	3,000,000
Preferred Stock, Dividend Rate, Percentage	10.00%
Preferred Stock, Conversion Basis	1
Common Stock For Conversion					554,402
Preferred Stock Number Of Authorized Shares Remaining					2,445,598
Preferred Stock, Shares Outstanding, Ending Balance				0