Note 2 - Convertible Debentures (Details Textual) - USD ($) | Feb. 29, 2016 | Feb. 16, 2016 | Aug. 31, 2015 | Feb. 29, 2016 | Feb. 29, 2016 | Aug. 31, 2015 | Mar. 31, 2016 | Dec. 31, 2015 | Mar. 31, 2015 | Dec. 31, 2015 | Mar. 31, 2016 | Mar. 31, 2015 | Jun. 30, 2015 |
Convertible Debt [Member] | Debt Issuance Cost Allocated to Debt [Member] | | | | | | | | | | | | | |
Debt Issuance Costs, Net | $ 183,000 | | | $ 183,000 | $ 183,000 | | | | | | | | |
Convertible Debt [Member] | Debt Issuance Cost Allocated to Equity [Member] | | | | | | | | | | | | | |
Debt Issuance Costs, Net | 37,000 | | | 37,000 | 37,000 | | | | | | | | |
Convertible Debt [Member] | | | | | | | | | | | | | |
Debt Instrument, Face Amount | $ 12,500,000 | | | $ 12,500,000 | $ 12,500,000 | | | | | | | | |
Debt Conversion, Convertible Shares | 3,676,471 | | | 3,676,471 | 3,676,471 | | | | | | | | |
Debt Instrument, Term | | | | | 3 years | | | | | | | | |
Debt Instrument, Interest Rate, Stated Percentage | 22.00% | | | 22.00% | 22.00% | | | | | | | | |
Debt Instrument, Convertible, Conversion Price | $ 3.40 | | | $ 3.40 | $ 3.40 | | | | | | | | |
Debt Conversion Convertible Shares, Upon Maturity | 6,102,941 | | | 6,102,941 | 6,102,941 | | | | | | | | |
Proceeds from Convertible Debt | | | | | $ 12,319,000 | | | | | | | | |
Warrants Not Settleable in Cash, Fair Value Disclosure | $ 4,434,000 | | | $ 4,434,000 | 4,434,000 | | | | | | | | |
Convertible Debt | 1,061,000 | | | 1,061,000 | 1,061,000 | | | | | | | | |
Debt Instrument, Unamortized Discount | 11,258,000 | | | 11,258,000 | 11,258,000 | | | | | | | | |
Amortization of Debt Discount (Premium) | | | | | | | $ 469,000 | | | | | | |
Amortization of Debt Issuance Costs | | | | | | | 8,000 | | | | | | |
Interest Expense | | | | | | | 344,000 | | | | | | |
Debt Instrument, Debt Default, Amount | | | | | | | 0 | | | | $ 0 | | |
Debentures, Beneficial Conversion Feature [Member] | | | | | | | | | | | | | |
Debt Instrument, Convertible, Beneficial Conversion Feature | | | | | $ 6,824,000 | | | | | | | | |
Thirty-Year Debentures [Member] | Series A Warrant [Member] | | | | | | | | | | | | | |
Residual Fair Value of Warrants | | | $ 3,385,000 | | | | | | | | | | |
Thirty-Year Debentures [Member] | Series B Warrant [Member] | | | | | | | | | | | | | |
Residual Fair Value of Warrants | | | $ 897,000 | | | | | | | | | | |
Class of Warrant or Right, Cancelled During Period,Value | | | | | | | 159,000 | | | | | | |
Thirty-Year Debentures [Member] | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | | | 1,102,942 | | | 1,102,942 | | | | | | | |
Debt Instrument, Term | | | 30 years | | | | | | | | | | |
Proceeds from Convertible Debt | | | $ 4,720,000 | | | | | | | | | | |
Convertible Debt | | | 0 | | | $ 0 | | | | | | | |
Debt Instrument, Unamortized Discount | | | 4,720,000 | | | 4,720,000 | | | | | | | |
Amortization of Debt Discount (Premium) | | $ 4,648,000 | | | | | 4,668,000 | | | | 4,720,000 | | |
Amortization of Debt Issuance Costs | | 765,000 | | | | | 768,000 | | | | 778,000 | | |
Potential Proceed from Issuance of Convertible Debt | | | | | | 15,000,000 | | | | | | | |
Gross Proceeds from Convertible Debt | | | | | | 5,500,000 | 5,500,000 | | | | | | |
Registration Payment Arrangement, Gains and Losses | | | | | | | | | | | $ 1,100,000 | | |
Registration Payment | | | | | | | | $ 220,000 | | | | | |
Repayments of Debt | | | | $ 7,500,000 | | | 7,500,000 | | | | | | |
Gain (Loss) on Extinguishment of Debt | | | | | | | $ (795,000) | | | | | | |
Payment After Approval of Authorities [Member] | | | | | | | | | | | | | |
Potential Proceed from Issuance of Convertible Debt | | | | | | $ 9,500,000 | | | | | | | |
Thirty-Year Debentures, Beneficial Conversion Feature [Member] | | | | | | | | | | | | | |
Debt Instrument, Convertible, Beneficial Conversion Feature | | | $ 438,000 | | | | | | | | | | |
Warrants [Member] | | | | | | | | | | | | | |
Fair Value Assumptions, Expected Term | | | | | 5 years | | | | | | | | |
Fair Value Assumptions, Expected Volatility Rate | | | | | 91.00% | | | | | | | | |
Fair Value Inputs, Discount Rate | | | | | 1.20% | | | | | | | | |
Series A Warrant [Member] | Other Expense [Member] | | | | | | | | | | | | | |
Derivative, Gain (Loss) on Derivative, Net | $ (149,000) | | | | | | | | | | | | |
Series A Warrant [Member] | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 8 | | $ 13.60 | $ 8 | $ 8 | $ 13.60 | | | | | | | |
Warrant Expiration Period | | | | | | 5 years 182 days | | | | | | | |
Fair Value Assumptions, Expected Term | 5 years | | | | | | | | | | | | |
Fair Value Assumptions, Expected Volatility Rate | 91.00% | | | | | | | | | | | | |
Fair Value Inputs, Discount Rate | 1.20% | | | | | | | | | | | | |
Class of Warrant or Right, Outstanding | | | 404,412 | | | 404,412 | 404,412 | | | | 404,412 | | |
Fair Value Assumptions, Expected Dividend Rate | 0.00% | | | | | | | | | | | | |
Series B Warrant [Member] | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | | | 606,618 | | | 606,618 | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | | | $ 13.60 | | | $ 13.60 | | | | | | | |
Warrant Expiration Period | | | | | | 1 year 180 days | | | | | | | |
Fair Value Assumptions, Expected Term | | | | | | | | | | 1 year 73 days | | | |
Fair Value Assumptions, Expected Volatility Rate | | | | | | | | | | 88.00% | | | |
Fair Value Inputs, Discount Rate | | | | | | | | | | 0.57% | | | |
Warrants Not Settleable in Cash, Fair Value Disclosure | | $ 25,000 | | | | | | $ 33,000 | | $ 33,000 | | | |
Class of Warrant or Right, Outstanding | | | 222,427 | | | 222,427 | 222,427 | | | | 222,427 | | |
Fair Value Assumptions, Expected Dividend Rate | | | | | | | | | | 0.00% | | | |
Shares Issued for Cashless Exercise of Warrants | | 125,000 | | | | | | 106,711 | | | | | |
Class of Warrant or Right, Cancelled During Period,Value | | $ 159,000 | | | | | | | | | | | |
Gross Proceeds from Financing Transaction | | | | | $ 15,000,000 | | | | | | | | |
Stock Issued During Period, Shares, New Issues | | | | | 735,294 | | | | | | | | |
Sale of Stock, Price Per Share | $ 3.40 | | | $ 3.40 | $ 3.40 | | | | | | | | |
Stock Issued During Period, Value, New Issues | | | | | $ 2,500 | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | 3,529,412 | | | 3,529,412 | 3,529,412 | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 8 | | | $ 8 | $ 8 | | | | | | | | |
Warrant Expiration Period | | | | | 5 years | | | | | | | | |
Number of Warrants, Percentage of Shares Issued or to Be Issued | | | | | 80.00% | | | | | | | | |
Debt Issuance Costs, Net | $ 220,000 | | | $ 220,000 | $ 220,000 | | $ 176,000 | | | | $ 176,000 | | $ 0 |
Period after Benchmark Reached | | | | | 15 days | | | | | | | | |
Net Cash and Short-Term Investment Benchmark | $ 2,100,000 | | | $ 2,100,000 | $ 2,100,000 | | | | | | | | |
Duration of Moving Average Price | | | | | 20 days | | | | | | | | |
Percent of Stock Price | | | | | 125.00% | | | | | | | | |
Consecutive Days of Weighted Average Trading Price | | | | | 10 days | | | | | | | | |
Share Price | $ 4 | | | $ 4 | $ 4 | | | | | | | | |
Fair Value Assumptions, Expected Term | | | | | | | | | | | 5 years | | |
Fair Value Assumptions, Expected Volatility Rate | | | | | | | | | | | 79.00% | | |
Proceeds from Convertible Debt | | | | | | | | | | | $ 18,000,000 | | |
Convertible Debt | | | | | | | 1,535,000 | | | | 1,535,000 | | |
Debt Instrument, Unamortized Discount | | | | | | | $ 10,789,000 | | | | 10,789,000 | | |
Amortization of Debt Discount (Premium) | | | | | | | | | | | 5,189,000 | | |
Amortization of Debt Issuance Costs | | | | | | | | | | | 785,000 | | |
Approval for Grant in Amount for Clinical Trial | | | $ 10,000,000 | | | $ 10,000,000 | | | | | | | |
Registration Payment Arrangement, Gains and Losses | | | | | | | | | | | $ (1,100,000) | | |
Fair Value Assumptions, Expected Dividend Rate | | | | | | | | | | | 0.00% | | |
Derivative, Gain (Loss) on Derivative, Net | | | | | | | $ (454,000) | | | | $ 3,152,000 | | |
Gain (Loss) on Extinguishment of Debt | | | | | | | $ (795,000) | | | | $ (795,000) | | |