12. SUBSEQUENT EVENTS	3 Months Ended
Jul. 31, 2015
Subsequent Events [Abstract]
12. SUBSEQUENT EVENTS	Sale of Common Stock June 2014 AMI Agreement - Subsequent to July 31, 2015 and through September 9, 2015, we sold 1,091,508 shares of common stock at market prices under the June 2014 AMI Agreement (Note 6) for aggregate gross proceeds of $1,290,000. As of September 9, 2015, we had raised the full amount of gross proceeds available to us under the June 2014 AMI Agreement. August 2015 AMI Agreement - On August 7, 2015, we entered into an At Market Issuance Sales Agreement (“August 2015 AMI Agreement”), with MLV, pursuant to which we may sell shares of our common stock through MLV, as agent, for aggregate gross proceeds of up to $30,000,000. The shares of our common stock issuable under the August 2015 AMI Agreement are registered for sale to the public pursuant to a prospectus supplement filed on August 7, 2015 with the SEC in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-201245). We will pay MLV a commission equal to 2.5% of the gross proceeds from the sale of our common stock pursuant to the August 2015 AMI Agreement. As of September 9, 2015, we sold 752,760 shares of common stock at market prices under the August 2015 AMI Agreement for aggregate gross proceeds of $892,000. Equity Distribution Agreement - On August 7, 2015, we entered into an Equity Distribution Agreement, with Noble International Investments, Inc., doing business as Noble Life Science Partners, a division of Noble Financial Capital Markets (“Noble”), pursuant to which we may sell shares of our common stock through Noble, as agent, for aggregate gross proceeds of up to $20,000,000. The shares of our common stock issuable under the Equity Distribution Agreement are registered for sale to the public pursuant to a prospectus supplement filed on August 7, 2015 with the SEC in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-201245). We will pay Noble a commission equal to 2.5% of the gross proceeds from the sale of our common stock pursuant to the Equity Distribution Agreement. As of September 9, 2015, we had not sold any shares of common stock under the Equity Distribution Agreement. Series E Preferred Stock Dividend On September 8, 2015, our Board of Directors declared a quarterly cash dividend of $0.65625 per share on our Series E Preferred Stock. The dividend payment is equivalent to an annualized 10.50% per share, based on the $25.00 per share stated liquidation preference, accruing from July 1, 2015 through September 30, 2015. The cash dividend is payable on October 1, 2015 to holders of the Series E Preferred Stock of record on September 18, 2015.

12. SUBSEQUENT EVENTS

3 Months Ended

Jul. 31, 2015

Sale of Common Stock

June 2014 AMI Agreement - Subsequent to July 31, 2015 and through September 9, 2015, we sold 1,091,508 shares of common stock at market prices under the June 2014 AMI Agreement (Note 6) for aggregate gross proceeds of $1,290,000. As of September 9, 2015, we had raised the full amount of gross proceeds available to us under the June 2014 AMI Agreement.

August 2015 AMI Agreement - On August 7, 2015, we entered into an At Market Issuance Sales Agreement (“August 2015 AMI Agreement”), with MLV, pursuant to which we may sell shares of our common stock through MLV, as agent, for aggregate gross proceeds of up to $30,000,000. The shares of our common stock issuable under the August 2015 AMI Agreement are registered for sale to the public pursuant to a prospectus supplement filed on August 7, 2015 with the SEC in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-201245). We will pay MLV a commission equal to 2.5% of the gross proceeds from the sale of our common stock pursuant to the August 2015 AMI Agreement. As of September 9, 2015, we sold 752,760 shares of common stock at market prices under the August 2015 AMI Agreement for aggregate gross proceeds of $892,000.

Equity Distribution Agreement - On August 7, 2015, we entered into an Equity Distribution Agreement, with Noble International Investments, Inc., doing business as Noble Life Science Partners, a division of Noble Financial Capital Markets (“Noble”), pursuant to which we may sell shares of our common stock through Noble, as agent, for aggregate gross proceeds of up to $20,000,000. The shares of our common stock issuable under the Equity Distribution Agreement are registered for sale to the public pursuant to a prospectus supplement filed on August 7, 2015 with the SEC in connection with a takedown from our shelf registration statement on Form S-3 (File No. 333-201245). We will pay Noble a commission equal to 2.5% of the gross proceeds from the sale of our common stock pursuant to the Equity Distribution Agreement. As of September 9, 2015, we had not sold any shares of common stock under the Equity Distribution Agreement.

Series E Preferred Stock Dividend

On September 8, 2015, our Board of Directors declared a quarterly cash dividend of $0.65625 per share on our Series E Preferred Stock. The dividend payment is equivalent to an annualized 10.50% per share, based on the $25.00 per share stated liquidation preference, accruing from July 1, 2015 through September 30, 2015. The cash dividend is payable on October 1, 2015 to holders of the Series E Preferred Stock of record on September 18, 2015.