Note 12 - Stockholders' Equity (Details Textual) - USD ($)			1 Months Ended		3 Months Ended						6 Months Ended
	Jun. 26, 2019	Mar. 29, 2019	Jun. 30, 2019	May 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Feb. 29, 2016	Jul. 31, 2011
Preferred Stock, Shares Authorized			5,000,000		5,000,000						5,000,000				5,000,000
Preferred Stock, Shares Outstanding, Ending Balance			0		0						0				0
Common Stock, Par or Stated Value Per Share			$ 0.01		$ 0.01						$ 0.01				$ 0.01
Stock Issued During Period, Value, New Issues					$ 2,467,000		$ 5,984,000
Common Stock, Shares Authorized			50,000,000		50,000,000						50,000,000				240,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 0.77		$ 0.77						$ 0.77				$ 1.81		$ 33.25
Additional Paid in Capital, Ending Balance			$ 123,518,000		$ 123,518,000						$ 123,518,000				$ 119,764,000
Warrants and Rights Outstanding			266,000		266,000						266,000				$ 178,000
Warrant, Down Round Feature, (Increase) Decrease in Equity, Amount					$ 29,000						$ 29,000
Class of Warrant or Right, Exercised During Period					158,400						291,000
Proceeds from Warrant Exercises											$ 46,000
Class of Warrant or Right, Issued During Period											1,371,000
Retained Earnings [Member]
Stock Issued During Period, Value, New Issues
Accounting Standards Update 2017-11 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										3,613,284
Warrants and Rights, Reclassified to Equity														210,586
Additional Paid in Capital, Ending Balance			56,000		56,000						$ 56,000		$ 56,000	$ 356,000
Warrants and Rights Outstanding			$ (56,000)		$ (56,000)						$ (56,000)		$ (56,000)
Accounting Standards Update 2017-11 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption														$ (356,000)
July 2011, March 2015, and October 2015 Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights									363,523
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.2061												$ 1.81
Class of Warrant or Right, Exercised During Period									363,523	3,613,284
Proceeds from Warrant Exercises									$ 900,000	$ 6,900,000
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			133,167
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			158,400		158,400						158,400
Warrants and Rights Outstanding			$ 400,000		$ 400,000						$ 400,000
Class of Warrant or Right, Exercised During Period					158,400
Proceeds from Warrant Exercises					$ 33,000
The June 2019 Warrants [Member]
Class of Warrant or Right Call Feature Minimum Stock Price			$ 1		$ 1						$ 1
Private Placement [Member]
Payments of Stock Issuance Costs	$ 27,000
Private Placement [Member] | The June 2019 Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			1,371,427		1,371,427						1,371,427
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 0.87		$ 0.87						$ 0.87
Class of Warrant or Right, Issued During Period			1,371,427
Warrants and Rights Outstanding, Term			1 year		1 year						1 year
OP Financial Investments Limited [Member] | Private Placement [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
China Kington Asset Management Co. Ltd. [Member] | Private Placement [Member]
Private Placement, Commission Percentage							6.00%
Payments of Stock Issuance Costs							$ 359,040
NYSE American [Member] | Private Placement [Member]
Payments of Stock Issuance Costs							$ 34,000
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
Common Stock, Par or Stated Value Per Share			$ 0.01		$ 0.01						$ 0.01
Stock Issued During Period, Value, New Issues					$ 360,121
Payments of Stock Issuance Costs					$ 122,000
Three Accredited Investors [Member] | Private Placement [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
Xiao Rui Liu [Member] | Private Placement [Member]
Issuance of Stock and Warrants During the Period, Value	1,000,000
Hai Dong Pang [Member] | Private Placement [Member]
Issuance of Stock and Warrants During the Period, Value	400,000
Ping Huang [Member] | Private Placement [Member]
Issuance of Stock and Warrants During the Period, Value	$ 1,000,000
China Kington [Member] | Private Placement [Member]
Private Placement, Commission Percentage	6.00%
Payments of Stock Issuance Costs	$ 144,000