Note 12 - Stockholders' Equity (Details Textual) - USD ($)						1 Months Ended				3 Months Ended				12 Months Ended
	Oct. 09, 2019	Sep. 05, 2019	Aug. 08, 2019	Jun. 26, 2019	Mar. 29, 2019	Aug. 31, 2019	Jul. 31, 2019	Jun. 30, 2019	May 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2018	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 13, 2019	Dec. 31, 2016	Feb. 29, 2016	Oct. 27, 2015	Jul. 31, 2011
Preferred Stock, Shares Authorized														5,000,000	5,000,000
Preferred Stock, Shares Outstanding, Ending Balance														0	0
Stock Issued During Period, Shares, New Issues			4,198,566							4,198,566
Payments of Stock Issuance Costs			$ 488,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs															$ 399,000
Common Stock, Par or Stated Value Per Share														$ 0.01	$ 0.01
Stock Issued During Period, Value, New Issues														$ 3,502,000	$ 5,984,000
Common Stock, Shares Authorized														50,000,000	240,000,000
Proceeds from Issuance of Common Stock			$ 4,200,000											$ 6,698,000	$ 5,585,000
Shares Issued, Price Per Share			$ 1																	$ 5
Class of Warrant or Right, Issued During Period														8,438,000
Class of Warrant or Right, Exercise Price of Warrants or Rights														$ 1.09	$ 1.81	$ 1.81		$ 1.81			$ 33.25
Additional Paid in Capital, Ending Balance														$ 125,718,000	$ 119,764,000
Warrant, Down Round Feature, (Increase) Decrease in Equity, Amount														$ 29,000
Class of Warrant or Right, Exercised During Period														394,000		21,000
Proceeds from Warrant Exercises														$ 67,000		$ 38,000
Triton Funds LP [Member]
Common Stock, Shares Authorized					3,000,000
Purchase Price, Percentage of Lowest Trading Price of Common Stock for Five Days Prior to Closing					90.00%
Triton Funds LLC [Member]
Stock Issued During Period, Shares, New Issues					150,000						1,747,312
Payments of Stock Issuance Costs											$ 122,000
Common Stock, Par or Stated Value Per Share								$ 0.01			$ 0.01
Stock Issued During Period, Value, New Issues											$ 360,000
Proceeds from Issuance of Common Stock		$ 288,000
Ladenburg Thalmann and Co. Inc. [Member]
Private Placement, Commission Percentage			6.00%
Payments of Stock Issuance Costs			$ 252,000
Payments of Stock Issuance Costs, Reimbursement of Expenses			60,000
Payments of Stock Issuance Costs, Other			312,000
Private Placement [Member]
Payments of Stock Issuance Costs			33,000	$ 27,000
Payments of Stock Issuance Costs Allocated to Warrants			$ 93,000
Private Placement [Member] | China Kington Asset Management Co. Ltd. [Member]
Private Placement, Commission Percentage			6.00%									6.00%
Payments of Stock Issuance Costs			$ 162,000									$ 359,000
Private Placement [Member] | OP Financial Investments Limited [Member]
Stock Issued During Period, Shares, New Issues												1,700,000
Common Stock, Par or Stated Value Per Share												$ 0.01
Stock Issued During Period, Value, New Issues												$ 5,984,000
Private Placement [Member] | NYSE American [Member]
Payments of Stock Issuance Costs												$ 34,000
Private Placement [Member] | Three Accredited Investors [Member]
Stock Issued During Period, Shares, New Issues				1,371,427
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				1,371,427
Issuance of Stock and Warrants During the Period, Value				$ 2,400,000
Private Placement [Member] | Xiao Rui Liu [Member]
Issuance of Stock and Warrants During the Period, Value				1,000,000
Private Placement [Member] | Hai Dong Pang [Member]
Issuance of Stock and Warrants During the Period, Value				400,000
Private Placement [Member] | Ping Huang [Member]
Issuance of Stock and Warrants During the Period, Value				$ 1,000,000
Private Placement [Member] | China Kington [Member]
Private Placement, Commission Percentage				6.00%
Payments of Stock Issuance Costs				$ 144,000
Conversion of Series A Preferred Stock to Common Stock [Member]
Conversion of Stock, Shares Issued	2,700,000
Convertible Preferred Stock, Shares Issued upon Conversion	1
Conversion of Stock, Shares Converted	2,700,000
The 2019 Foreign Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,700,000		2,700,000			2,700,000
Warrants and Rights Outstanding			$ 2,000,000											1,550,000			$ 2,000,000
Class of Warrant or Right, Issued During Period						2,700,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 1.15					$ 1.15
The 2019 Domestic Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			4,198,566			4,198,566
Warrants and Rights Outstanding			$ 3,100,000											2,410,000			$ 3,100,000
Payments of Stock Issuance Costs Allocated to Warrants			$ 233,000
Class of Warrant or Right, Issued During Period			4,198,566			4,198,566
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 1.15			$ 1.15											$ 1.15
Common Stock, Closing Price			$ 2
Additional Paid in Capital, Ending Balance			$ (255,000)
The 2019 Ladenburg Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights						167,942
Warrants and Rights Outstanding														95,000			$ 124,000
Payments of Stock Issuance Costs Allocated to Warrants			59,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			$ 65,000
Class of Warrant or Right, Issued During Period						167,942
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 1.25			$ 1.25											$ 1.25
The 2019 Ladenburg Warrants [Member] | Ladenburg Thalmann and Co. Inc. [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			167,942
July 2011, March 2015, and October 2015 Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 0.2061										$ 1.81
March 2015 Short-term and Long-term Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights								133,167			133,167		21,000
Warrant, Down Round Feature, (Increase) Decrease in Equity, Amount									$ 29,000
Class of Warrant or Right, Exercised During Period											133,167		21,000
Proceeds from Warrant Exercises											$ 13,000		$ 38,000
Class of Warrant or Right, Exercised During Period, Cashless Exercise											70,000
Stock Issued In Connection with Exercise of Warrants, Shares											64,979
July 2011 and October 2015 Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights							102,602	158,400		102,602	158,400
Warrants and Rights Outstanding								$ 400,000		$ 200,000	$ 400,000
Class of Warrant or Right, Exercised During Period							102,602			102,602	158,400
Proceeds from Warrant Exercises							$ 21,000			$ 21,000	$ 33,000
The June 2019 Warrants [Member]
Class of Warrant or Right Call Feature Minimum Stock Price								$ 1			$ 1
The June 2019 Warrants [Member] | Private Placement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights								1,371,427			1,371,427
Class of Warrant or Right, Issued During Period								1,371,427
Class of Warrant or Right, Exercise Price of Warrants or Rights								$ 0.87			$ 0.87
Warrants and Rights Outstanding, Term								1 year			1 year
Series A Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues			2,700,000
Proceeds from Issuance of Preferred Stock and Preference Stock			$ 2,700,000
Adjustments to Additional Paid in Capital, Beneficial Conversion Feature Upon Issuance of Stock	$ 800,000													$ 800,000
Series A Preferred Stock [Member] | Private Placement [Member]
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs			$ 102,000