Note 7 - Stockholders' Equity (Details Textual)		3 Months Ended			6 Months Ended	9 Months Ended
	May 30, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($)	May 29, 2018 $ / shares	May 09, 2018 $ / item shares	Dec. 31, 2017 $ / shares shares	May 19, 2014 $ / shares shares
Number of Shares Authorized to Issue		185,000,000				185,000,000
Common Stock, Shares Authorized		175,000,000				175,000,000				175,000,000
Common Stock, Par or Stated Value Per Share | $ / shares		$ 0.18				$ 0.18				$ 0.18
Preferred Stock, Shares Authorized		10,000,000				10,000,000				10,000,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.001				$ 0.001				$ 0.001
Stockholder Rights Agreement, Number of Preferred Stock Right Distributed for Each Share of Common Stock											1
Stockholder Rights Agreement, Acquiring Person, Percentage of Ownership											15.00%
Stockholder Rights Agreement, Acquiring Person, Additional Percentage of Ownership											2.00%
Stockholder Rights Agreement, Initial Exercise Price of Each Right | $ / shares											$ 15
Stockholder Rights Agreement, Share Price | $ / shares											$ 30
Class of Warrant or Right, Outstanding		4,318,475				4,318,475
Consummate a Business Combination, Percentage of Acquired Outstanding Shares		50.00%				50.00%
Consummate a Business Combination, Percentage of Aggregate Ordinary Voting Power		50.00%				50.00%
Preferred Stock, Deemed Dividend | $			$ 11,479,308		$ 11,479,308	$ 11,479,308	$ 2,568,132
Payments of Stock Issuance Costs | $						$ 1,333,449
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		4,318,475				4,318,475
Conversion of Stock, Shares Converted		2,285				10,107
The 2018 Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 4.048	$ 4.048				$ 4.048
Warrants and Rights Outstanding, Term		4 years				4 years
Warrants Exercisable, Ownership Percentage of Company’s Shares Allowed		4.99%				4.99%
Warrants and Rights Outstanding, Redemption Price | $ / shares		$ 0.18				$ 0.18
Warrants and Rights Outstanding, Redeemable, Volume-weighted-average-price of Our Common Stock | $ / shares		$ 10.56				$ 10.56
The 2018 Subscription Rights Offering [Member]
Number of Units Authorized to Purchase, Maximum									25,000
Purchase Price of Unit | $ / item									1,000
Number of Series B Convertible Preferred Stock and Warrant in Each Unit									1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right									284
Number of Units Sold	13,624
Proceeds from Issuance of Stock units | $	$ 12,300,000
Adjustments to Additional Paid in Capital, Beneficial Conversion Feature on Preferred Stock | $						$ 4,782,100
Preferred Stock, Deemed Dividend | $						11,479,308
Payments of Stock Issuance Costs | $						1,333,449
The 2018 Subscription Rights Offering [Member] | The 2018 Warrants [Member]
Class of Warrant or Right, Outstanding	3,869,216
Warrants Allocated to Common Stock , Net of Issuance Cost | $		$ 5,363,759				$ 5,363,759
Series A Junior Participating Preferred Stock [Member]
Preferred Stock, Shares Authorized		750,000				750,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.001				$ 0.001
Preferred Stock, Shares Issued, Total		0				0
Preferred Stock, Shares Outstanding, Ending Balance		0				0
Series A Convertible Preferred Stock [Member]
Preferred Stock, Shares Authorized		4,000				4,000				4,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.001				$ 0.001				$ 0.001
Preferred Stock, Shares Issued, Total		0				0
Preferred Stock, Shares Outstanding, Ending Balance		0				0				0
Series B Convertible Preferred Stock [Member]
Preferred Stock, Shares Authorized		25,000				25,000				0
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.001				$ 0.001		$ 0.001		$ 0.001
Preferred Stock, Shares Issued, Total		3,517				3,517				0
Stated Value per Share | $ / shares		1,000				1,000
Preferred Stock, Convertible, Conversion Price | $ / shares		$ 3.52				$ 3.52
Preferred Stock, Convertible, Ownership Percentage of Company’s Shares Allowed		9.99%				9.99%
Convertible Preferred Stock, Shares Issued upon Conversion		284				284
Preferred Stock, Shares Outstanding, Ending Balance		3,517				3,517				0
Series B Convertible Preferred Stock [Member] | The 2018 Subscription Rights Offering [Member]
Stock Issued During Period, Shares, New Issues	13,624
Common Stock [Member]
Conversion of Stock, Shares Issued		649,156				2,871,303