Note 13 - Preferred Stock and Warrants (Details Textual) - USD ($) | Mar. 26, 2018 | Apr. 27, 2017 | Jun. 30, 2018 | Mar. 31, 2018 | Mar. 25, 2018 | Jan. 19, 2016 |
PFG Loan [Member] | | | | | | |
Stock Issued During Period, Shares, New Issues | | 190,000 | | | | |
Debt Instrument, Amount of Indebtedness Restructured | $ 1,700,000 | | | | | |
Series E Preferred Stock Warrants [Member] | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights, Percentage of Common Shares Into Which the Preferred Shares Can Be Converted | 5.00% | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | 223,000 | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 0.25 | | | | | |
The 2016 Warrants [Member] | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | | | | | | 2,787,872 |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 0.25 | | | | | $ 1.15 |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | | | | | | 0.75 |
Class of Warrant or Right, Exercise Price of Warrants or Rights, Alternative Price for Certain Investors | | | | | | $ 0.25 |
Class of Warrant or Right, Exercise Price Reduction, Number | 1,759,268 | | | | | |
Placement Agent Warrants [Member] | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 0.25 | | | | $ 1.15 | |
Class of Warrant or Right, Exercise Price Reduction, Number | 292,727 | | | | | |
Series E Preferred Stock [Member] | | | | | | |
Stock Issued During Period, Shares, New Issues | 43,800 | | 8,800 | | | |
Preferred Stock, Dividend Rate, Percentage | 6.00% | | | | | |
Issuance of Stock, Number of Investors | 15 | | | | | |
Shares Issued, Price Per Share | $ 25 | | $ 25 | | | |
Proceeds from Issuance of Preferred Stock and Preference Stock | $ 1,095,000 | | | | | |
Proceeds from Issuance of Preferred Stock and Preference Stock, Net of Issuance Costs | $ 1,000,000 | | | | | |
Stock Issued During Period, Placement Agent Fees, Percentage of Gross Proceeds | 5.00% | | | | | |
Payments of Stock Issuance Costs | $ 57,000 | | | | | |
Convertible Preferred Stock, Conversion Price Per Share | $ 0.25 | | | | | |
Convertible Preferred Stock, Shares Issued upon Conversion | 100 | | | | | |
Convertible Preferred Stock, Common Shares That Would Be Issued If All Preferred Shares Were Converted | | | | 4,380,000 | | |
Convertible Preferred Stock, Common Shares That Would Be Issued If All Preferred Shares Were Converted, Percentage of Pro Forma Common Stock | | | | 31.00% | | |
Convertible Preferred Stock, Common Shares That Would Be Issued If All Preferred Shares Were Converted, Percentage of Pro Forma Common Stock If All Classes of Convertible Preferred Stock Were Converted | | | | 27.00% | | |
Convertible Preferred Stock, Common Shares That Would Be Issued If All Preferred Shares Were Converted, Percentage of Pro Forma Common Stock If All Convertible Preferred Stock Were Converted and All Warrants Exercised | | | | 22.00% | | |
Preferred Stock, Redemption Price Percentage | | | | 300.00% | | |
Preferred Stock, Redemption Price Per Share | | | | $ 75 | | |
Preferred Stock, Liquidation Preference, Percentage | 150.00% | | | | | |
Preferred Stock, Liquidation Preference Per Share | $ 37.50 | | | | | |
Convertible Preferred Stock, Termination of Right to Approve Parity Securities, Threshold Shares | 22,300 | | | | | |
Convertible Preferred Stock, Termination of Right to Approve Parity Securities, Threshold Percentage | 50.00% | | | | | |
Convertible Preferred Stock, Termination of Right to Approve Parity Securities, Threshold Closing Price | $ 0.75 | | | | | |
Convertible Preferred Stock, Termination of Right to Approve Parity Securities, Threshold Trading Volume | 100,000 | | | | | |
Preferred Stock, Investor Rights Agreement, Period During Which Payment-in-kind Dividends May Potentially Be Received | 2 years | | | | | |
Preferred Stock, Investor Rights Agreement, Ability to Issue Additional Debt Other Than Trade Debt and Commercial Bank Working Capital Debt, Required Percentage of Approval By Holders | 66.60% | | | | | |
Issuance of Preferred Stock, Amount Deducted from Gross Proceeds Attributable to the Re-pricing of Warrants | $ 203,000 | | | | | |
Beneficial Conversion Feature Upon Issuance of Preferred Shares | 557,000 | | | | | |
Fair Value of Warrants Issued as Issuance Costs for Preferred Stock | 53,000 | | | | | |
Proceeds from Issuance of Convertible Preferred Stock | 1,095,000 | | $ 220,000 | | | |
Series E Preferred Stock [Member] | The 2016 Warrants [Member] | | | | | | |
Class of Warrant or Right, Alternative Exercise Price, Criteria, Amount of Preferred Stock Purchased | $ 200,000 | | | | | |
Class of Warrant or Right, Alternative Exercise Price, Criteria, Percentage of Preferred Stock Purchased | 50.00% | | | | | |