Note 8 - Preferred Stock and Warrants (Details Textual) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				500,000
Preferred Stock, Liquidation Preference Per Share				$ 1,000
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 8.40
Series A Preferred Stock [Member]
Stock Redeemed or Called During Period, Shares	9,360	8,661	9,979
Preferred Stock, Shares Outstanding				0
Preferred Stock, Redemption Price Per Share		$ 1,000	$ 1,000