Note 12 - Stockholders' Equity (Deficit) (Details Textual) - USD ($) | Mar. 06, 2020 | Oct. 09, 2019 | Sep. 05, 2019 | Aug. 08, 2019 | Jun. 26, 2019 | Mar. 29, 2019 | Aug. 31, 2019 | Jul. 31, 2019 | Jun. 30, 2019 | Mar. 31, 2020 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2019 | Aug. 13, 2019 | May 31, 2019 | Feb. 29, 2016 | Oct. 27, 2015 | Jul. 31, 2011 |
Preferred Stock, Shares Authorized (in shares) | | | | | | | | | | 5,000,000 | | | | | 5,000,000 | | | | | |
Preferred Stock, Shares Outstanding, Ending Balance (in shares) | | | | | | | | | | 0 | | | | | 0 | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | 4,198,566 | | | | | | | 4,198,566 | | | | | | | | | |
Payments of Stock Issuance Costs | | | | $ 488,000 | | | | | | | | | | | | | | | | |
Common Stock, Par or Stated Value Per Share (in dollars per share) | | | | | | | | | | $ 0.01 | | | | | $ 0.01 | | | | | |
Common Stock, Shares Authorized (in shares) | | | | | | | | | | 50,000,000 | | | | | 240,000,000 | | | | | |
Proceeds from Issuance of Common Stock | | | | $ 4,200,000 | | | | | | | | | | | | | | | | |
Shares Issued, Price Per Share (in dollars per share) | | | | $ 1 | | | | | | | | | | | | | | | $ 5 | |
Class of Warrant or Right, Issued During Period (in shares) | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | | | | | | | $ 1.11 | | | | | $ 1.09 | | | | | $ 33.25 |
Additional Paid in Capital, Ending Balance | | | | | | | | | | $ 125,975,000 | | | | | $ 125,718,000 | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | | 299,000 | | | | | | | | | | |
Proceeds from Warrant Exercises | | | | | | | | | | $ 201,000 | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 8,247,000 | | | | | 8,588,000 | | | | | |
Conversion of Series A Preferred Stock to Common Stock [Member] | | | | | | | | | | | | | | | | | | | | |
Conversion of Stock, Shares Converted (in shares) | | 2,700,000 | | | | | | | | | | | | | | | | | | |
Conversion of Stock, Shares Issued (in shares) | | 2,700,000 | | | | | | | | | | | | | | | | | | |
Triton Funds LP [Member] | | | | | | | | | | | | | | | | | | | | |
Common Stock, Shares Authorized (in shares) | | | | | | 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 (in shares) | | | | | | 150,000 | | | | | | 1,747,312 | | | | | | | | |
Payments of Stock Issuance Costs | | | | | | | | | | | | $ 122,000 | | | | | | | | |
Common Stock, Par or Stated Value Per Share (in dollars 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 (in shares) | | | | | | | | | | | | | | 1,700,000 | | | | | | |
Common Stock, Par or Stated Value Per Share (in dollars 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 (in shares) | | | | | 1,371,427 | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | 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 | | | | | | | | | | | | | | | |
The 2019 Foreign Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | 2,700,000 | | 2,700,000 | | | 2,700,000 | | | | | | | | | | | | | |
Warrants and Rights Outstanding | | | | $ 2,000,000 | | | | | | $ 1,504,000 | | | | | | $ 2,000,000 | | | | |
Class of Warrant or Right, Issued During Period (in shares) | | | | | | | 2,700,000 | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | $ 1.15 | | | | | $ 1.15 | | | | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 2,700,000 | | | | | | | | | | |
The 2019 Domestic Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 4,198,566 | | | 4,198,566 | | | | | | | | | | | | | |
Warrants and Rights Outstanding | | | | $ 3,100,000 | | | | | | $ 2,339,000 | | | | | | $ 3,100,000 | | | | |
Payments of Stock Issuance Costs Allocated to Warrants | | | | $ 233,000 | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Issued During Period (in shares) | | | | 4,198,566 | | | 4,198,566 | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | $ 1.15 | | | $ 1.15 | | | | | | | | | $ 1.15 | | | | |
Common Stock, Closing Price (in dollars per share) | | | | $ 2 | | | | | | | | | | | | | | | | |
Additional Paid in Capital, Ending Balance | | | | $ (255,000) | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 4,199,000 | | | | | | | | | | |
The 2019 Ladenburg Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | 167,942 | | | | | | | | | | | | | |
Warrants and Rights Outstanding | | | | | | | | | | $ 92,000 | | | | | | $ 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 (in shares) | | | | | | | 167,942 | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | $ 1.25 | | | $ 1.25 | | | | | | | | | $ 1.25 | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 168,000 | | | | | | | | | | |
The 2019 Ladenburg Warrants [Member] | Ladenburg Thalmann and Co. Inc. [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | 167,942 | | | | | | | | | | | | | | | | |
July 2011, March 2015, and October 2015 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | | | | | | | | | | | | | | $ 0.2061 | $ 1.81 | | |
July 2011 and October 2015 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | 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 (in shares) | | | | | | | | 102,602 | | | 102,602 | 158,400 | | | | | | | | |
Proceeds from Warrant Exercises | | | | | | | | $ 21,000 | | | $ 21,000 | $ 33,000 | | | | | | | | |
March 2015 Short-term and Long-term Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | | 133,167 | 70,000 | | 133,167 | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | | 70,000 | | 133,167 | | | | | | | | |
Proceeds from Warrant Exercises | | | | | | | | | | $ 14,000 | | $ 13,000 | | | | | | | | |
Class of Warrant or Right, Exercised During Period, Cashless Exercise (in shares) | | | | | | | | | | | | 70,000 | | | | | | | | |
Stock Issued In Connection with Exercise of Warrants, Shares (in shares) | | | | | | | | | | | | 64,979 | | | | | | | | |
The June 2019 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | | | 228,571 | | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | | | | | | | | 228,571 | | | | | | | | | | |
Class of Warrant or Right Call Feature Minimum Stock Price (in dollars per share) | | | | | | | | | $ 1 | | | $ 1 | | | | | | | | |
Adjustments to Additional Paid in Capital, Warrant Issued | | | | | | | | | | $ 199,000 | | | | | | | | | | |
The June 2019 Warrants [Member] | China Kington [Member] | | | | | | | | | | | | | | | | | | | | |
Exercise of Warrants, Commission, Percent | | | | | | | | | | 6.00% | | | | | | | | | | |
Payments for Commission, Exercise of Warrants | | | | | | | | | | $ 12,000 | | | | | | | | | | |
The June 2019 Warrants [Member] | Private Placement [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | | 1,371,427 | | | 1,371,427 | | | | | | | | |
Class of Warrant or Right, Issued During Period (in shares) | | | | | | | | | 1,371,427 | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | | | | | | | $ 0.87 | | | $ 0.87 | | | | | | | | |
Warrants and Rights Outstanding, Term (Month) | | | | | | | | | 1 year | | | 1 year | | | | | | | | |
The July 2011 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Warrants and Rights Outstanding | | | | | | | | | | $ 0 | | | | | | | | | | |
Class of Warrant or Right, Expired During Period (in shares) | 35,107 | | | | | | | | | 35,107 | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 0 | | | | | | | | | | |
October 2015 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Expired During Period (in shares) | 7,419 | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 38,000 | | | | | | | | | | |
The March 2015 Warrants [Member] | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Expired During Period (in shares) | 7,419 | | | | | | | | | 7,419 | | | | | | | | | | |
Class of Warrant or Right, Outstanding (in shares) | | | | | | | | | | 0 | | | | | | | | | | |
Series A Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | 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 | | | | | | | | | | | | | | | | | | |
Series A Preferred Stock [Member] | Private Placement [Member] | | | | | | | | | | | | | | | | | | | | |
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs | | | | $ 102,000 | | | | | | | | | | | | | | | | |