| Stockholders' Equity Note Disclosure [Text Block] |
4. STOCKHOLDERS’ EQUITY
Common Stock Warrants
The following table summarizes information with regard to outstanding warrants to purchase common stock as of March 31, 2014. | Offering | | Number of Shares
Issuable Upon
Exercise of
Outstanding
Warrants | | Exercise
Price | | Expiration Date | | | | | | | | | | | | | | February 2014 Private Placement (1) | | | 8,000,000 | | $ | 1.00 | | February 6, 2019 | | | February 2013 Public Offering (2) | | | 11,000,000 | | | 0.50 | | February 20, 2018 | | | February 2013 Public Offering – Placement Agents | | | 770,000 | | | 0.625 | | February 4, 2018 | | | November 2012 Private Placement | | | 1,000,000 | | | 1.25 | | November 2, 2017 | | | June 2012 Public Offering | | | 2,981,440 | | | 1.25 | | June 13, 2017 | | | December 2011 Underwritten Offering | | | 9,248,334 | | | 0.60 | | December 6, 2016 | | | April 2011 Private Placement | | | 6,058,811 | | | 0.75 | | March 31, 2016 | | | Legacy warrants (2) | | | 27,310 | | | 0.50 | | July 27, 2015 | | | Legacy warrants | | | 105,040 | | | 16.065 | | July 27, 2015 | | | Legacy warrants | | | 91,524 | | | 99.45-100.98 | | December 31, 2015 | | | | | | | | | | | | | | Total | | | 39,282,459 | | | | | | | | (1) | Warrants issued in connection with the sale of convertible debentures. As described in Note 3, the warrants are only exercisable following conversion of the associated debentures. | | (2) | The exercise prices of these warrants are subject to adjustment for “down-rounds” and the warrants have been accounted for as a derivative instrument as described in Note 2.
| On February 20, 2014, warrants to purchase 5,500,000 shares of common stock issued in connection with the February 2013 Public Offering, having an exercise price of $0.50 per share, expired unexercised.
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