Note 12 - Equity  | 
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2019  | |||
| Notes to Financial Statements | |||
| Stockholders' Equity Note Disclosure [Text Block] | 
 On    March 22, 2019,  the Company entered into a Stock Purchase Agreement with the Investor, pursuant to which the Company was to issue to the Investor in a private placement (the “Private Placement”) up to $3.0  million in shares (the “Securities”) of Common Stock. The Private Placement was to occur in multiple tranches. The initial closing occurred on  March 22, 2019 ( the “Initial Closing”), at which the Investor purchased $50,000  worth of the Securities at a per share price of $2.80,  which was the closing price of a share of Common Stock reported on the NYSE American market for the business day immediately before the Initial Closing Date. The remainder of the Securities were to be purchased by the Investor from time to time, on such date or dates to be determined by the Company and the Investor, which date was not  to be later than  June 15, 2019.   
No  additional shares were purchased by the Investor prior to the  June 15, 2019  expiration of the Stock Purchase Agreement.On    June 18, 2019,  the Company completed an underwritten public offering of 8,000,000  Shares of Common Stock pursuant to the Underwriting Agreement at a price to the public of $0.75  per share.  Of the 8,000,000  total Shares, 4,000,000  shares were placed with the Investor at a price of $0.75  per share. Pursuant to the Underwriting Agreement, the Underwriter purchased the remaining 4,000,000  Shares from the Company at a price of $0.69375  per share.  Under the terms of the Underwriting Agreement, the Company granted the Underwriter an option (the “Underwriter Option”), exercisable for 30  days, to purchase up to an additional 1,200,000  shares of Common Stock at a price per share of $0.69375.  The Underwriter Option was not  exercised. The Company paid the Underwriter (a) a management fee equal to   1.0%  of the gross proceeds raised in the offering, (b) $50,000  for non-accountable expenses, (c) $100,000  for fees and expenses of legal counsel to the Underwriter and other out-of-pocket expenses, and (d) $10,000  for clearing expenses. After underwriting discounts, commissions, fees and expenses paid to the Underwriter, the Company received net proceeds from the offering of $5,555,000.   The Company intends to use the net proceeds from the offering to fund its research and development programs, including continuing to advance its Phase 2b  and Phase 3  clinical trials of Tc99m  tilmanocept in patients with rheumatoid arthritis, and for general working capital purposes and other operating expenses.During the   nine -month period ended  September 30, 2018,  we issued 55,938  shares of Common Stock valued at $317,000  to our employees as payment in lieu of cash for their 2017  bonuses.During the  
nine -month periods ended  September 30, 2019  and 2018,  we issued 8,128  and 4,734  shares of Common Stock as matching contributions to our 401 (k) Plan which were valued at $20,000  and $36,000,  respectively. |