Note 8 - Convertible Preferred Stock and Common Stock Warrants (Details Textual)		1 Months Ended	3 Months Ended		9 Months Ended		10 Months Ended
	Mar. 31, 2017 $ / shares shares	Mar. 31, 2017 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) $ / item shares	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) $ / shares $ / item shares	Sep. 30, 2016 USD ($)	Jan. 07, 2018 USD ($)	Mar. 14, 2017 $ / item
Proceeds from Issuance of Convertible Preferred Stock, Net of Offering Costs					$ 22,129,774
Warrant Expense					10,225,846
Dividends					912,946
Stock Reclassified Upon Conversion of Preferred Stock					$ 187,172
Make-Whole Provision Conversion Price, Percentage					105.00%
Fair Value Adjustment of Warrants			$ (8,441,616)		$ (18,909,792)
Maximum [Member]
Convertible Preferred Stock, Conversion Price | shares			2.02		2.02
Minimum [Member]
Financing Trigger from Issuance of Common Stock			$ 10,000,000		$ 10,000,000
Convertible Preferred Stock, Make-Whole Provision, Proceeds from Issue of Common Stock					10,000,000
Warrant [Member]
Warrant Expense			$ 5,800,000		$ 5,800,000
Class of Warrant or Rights, Expired | shares					13,000
Private Placement [Member]
Convertible Preferred Stock, Votes Per Share | $ / item			0.50627		0.50627			0.84874
Private Placement [Member] | Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares	1	1
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 2.22	$ 2.22
Class of Warrant or Right, Term	5 years
Warrant Expense					$ 10,200,000
Series A Preferred Stock [Member]
Preferred Stock, Shares Authorized | shares			13,750,000		13,750,000
Proceeds from Issuance of Private Placement					$ 0
Dividends					$ 912,946
Conversion of Stock, Shares Converted | shares			2,125,306		4,052,297
Stock Reclassified Upon Conversion of Preferred Stock			$ 100,000		$ 200,000
Stock Reclassified Upon Conversion of Preferred Stock, Shares | shares			62,701		88,436
Fair Value Adjustment of Warrants			$ 8,400,000		$ 8,400,000
Series A Preferred Stock [Member] | Maximum [Member]
Convertible Preferred Stock, Make-Whole Provision, Minimum Share Price | $ / shares					$ 8
Series A Preferred Stock [Member] | Private Placement [Member]
Proceeds from Issuance of Private Placement		$ 25,000,000
Number of Convertible Preferred Stock Per Unit | shares	1	1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares	1	1
Preferred Stock, Dividend Rate, Percentage	8.00%
Number of Common Stock Per Unit | shares	1
Convertible Preferred Stock, Conversion Price | shares	2.02	2.02
Temporary Equity, Stock Issued During Period, New Issues | shares		12,376,329
Proceeds from Issuance of Convertible Preferred Stock, Net of Offering Costs		$ 22,100,000
Payments of Stock Issuance Costs		$ 2,900,000					$ 2,900,000
Class of Warrant or Right, Granted During Period | shares		1,179,558
Dividends			$ 400,000		$ 900,000
Series B Preferred Stock [Member] | Private Placement [Member] | Placement Agent [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 2.22	$ 2.22
Class of Warrant or Right, Term	5 years
Class of Warrant or Right, Granted During Period | shares		1,179,558