Note 9 - Notes Payable  | 
9 Months Ended | ||
|---|---|---|---|
Sep. 30, 2019  | |||
| Notes to Financial Statements | |||
| Debt Disclosure [Text Block] | 
 Platinum-Montaur Life Sciences LLC In    July 2012,  we entered into an agreement with Platinum-Montaur to provide us with a credit facility of up to $50  million (the “Platinum Loan Agreement”).  In  March 2017,  the Company repaid to PPCO an aggregate of approximately $7.7  million in partial satisfaction of the Company’s liabilities, obligations and indebtedness under the Platinum Loan Agreement between the Company and Platinum-Montaur, which were transferred by Platinum-Montaur to PPCO.  In  November 2018,  the Company issued 925,000  shares of our Common Stock to Dr. Goldberg, of which approximately 817,857  shares valued at $3.2  million were applied as payment of the Platinum debt, including principal and accrued interest of $2.2  million and loss on extinguishment of debt of $1.0  million.  See Note 11. 
During the   nine -month period ended  September 30, 2018,  
$129,000  of interest was compounded and added to the balance of the Platinum Note.IPFS Corporation In    November 2017,  we prepaid $396,000  of insurance premiums through the issuance of a note payable to IPFS Corporation (“IPFS”) with an interest rate of 4.0%.  The note was payable in ten  monthly installments of $40,000,  with the final payment made in  August 2018.  In  November 2018,  we prepaid $393,000  of insurance premiums through the issuance of a note payable to IPFS with an interest rate of 5.1%.  The note was payable in ten  monthly installments of $40,000,  with the final payment made in  August 2019. 
Interest expense related to the IPFS notes payable totaled   $6,000  and $5,000  during the nine -month periods ended  September 30, 2019  and 2018,  respectively. The balance of the IPFS note was approximately $0  and $316,000  as of  September 30, 2019  and  December 31, 2018,  respectively, and was included in notes payable, current in the consolidated balance sheets.Summary During the  
three -month periods ended  September 30, 2019  and 2018,  we recorded interest expense of $1,000  and $45,000,  respectively, related to our notes payable. Of these amounts, $0  and $44,000  was compounded and added to the balance of our notes payable during the three -month periods ended  September 30, 2019  and 2018,  respectively. During the nine -month periods ended  September 30, 2019  and 2018,  we recorded interest expense of $6,000  and $134,000,  respectively, related to our notes payable. Of these amounts, $0  and $129,000  was compounded and added to the balance of our notes payable during the nine -month periods ended  September 30, 2019  and 2018,  respectively. |