8. STOCKHOLDERS EQUITY

9 Months Ended

Jan. 31, 2013

STOCKHOLDERS' EQUITY:

8. STOCKHOLDERS EQUITY

December 2010 AMI Agreement.

On December 29, 2010, we entered into an At Market Sales Issuance Agreement (the “December 2010 AMI Agreement”) with McNicoll, Lewis & Vlak LLC (now known as MLV & Co. LLC, “MLV”), pursuant to which we may sell shares of our common stock at market prices through MLV, as agent, in registered transactions from the Company’s shelf registration statement on Form S-3 (File No. 333-171252) filed with the SEC on December 29, 2010, for aggregate gross proceeds of up to $75,000,000.

During the nine months ended January 31, 2013, we sold 31,662,214 shares of common stock at varying market prices under the December 2010 AMI Agreement for aggregate gross proceeds of $27,051,000 before deducting commissions and other issuance costs of $885,000. As of January 31, 2013, aggregate gross proceeds of up to $330,000 remained available under the December 2010 AMI Agreement.

Subsequent to January 31, 2013 and through March 12, 2013, we sold 201,154 shares of common stock at market prices under the December 2010 AMI Agreement for aggregate gross proceeds of $330,000. As of March 12, 2013, we had raised the full amount of gross proceeds available under the December 2010 AMI Agreement.

December 2012 AMI Agreement

On December 27, 2012, we entered into an At Market Sales Issuance Agreement (the “December 2012 AMI Agreement”) with MLV, pursuant to which we may sell shares of our common stock at market prices through MLV, as agent, for aggregate gross proceeds of up to $75,000,000, in registered transactions from the Company’s shelf registration statement on Form S-3 (File No. 333-180028), filed with the SEC on March 9, 2012. As of January 31, 2013, we had not sold any shares of common stock under the December 2012 AMI Agreement.

Subsequent to January 31, 2013 and through March 12, 2013, we sold 3,132,402 shares of common stock at market prices under the December 2012 AMI Agreement for aggregate gross proceeds of $4,475,000. As of March 12, 2013, aggregate gross proceeds of up to $70,525,000 remained available under the December 2012 AMI Agreement.

Shares of Common Stock Authorized And Reserved For Future Issuance

As of January 31, 2013, we had reserved 24,414,094 additional shares of our common stock, which may be issued under our equity compensation plans and outstanding warrant agreements, excluding shares of common stock that could potentially be issued under our current effective shelf registration statements, as further described in the following table:

	Number of Shares Reserved
Common shares reserved for issuance under outstanding option grants and available for issuance under our stock incentive plans		20,150,287
Common shares reserved for and available for issuance under our Employee Stock Purchase Plan		3,889,004
Common shares issuable upon exercise of outstanding warrants		374,803
Total shares of common stock reserved for issuance		24,414,094