8. STOCKHOLDERS EQUITY

6 Months Ended

Oct. 31, 2012

STOCKHOLDERS' EQUITY:

8. STOCKHOLDERS EQUITY

On December 29, 2010, we entered into an At Market Sales Issuance Agreement (the “December 2010 AMI Agreement”) with McNicoll, Lewis & Vlak 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 six months ended October 31, 2012, we sold 21,310,619 shares of common stock at varying market prices under the December 2010 AMI Agreement for aggregate gross proceeds of $18,215,000 before deducting commissions and other issuance costs of $620,000. As of October 31, 2012, aggregate gross proceeds of up to $9,167,000 remained available under the December 2010 AMI Agreement.

As of October 31, 2012, aggregate gross proceeds of up to $159,167,000 remained available under two effective shelf registration statements.

Subsequent to October 31, 2012 and through November 30, 2012, we sold 9,220,313 shares of common stock at market prices under the December 2010 AMI Agreement for aggregate gross proceeds of $7,296,000. As of November 30, 2012, aggregate gross proceeds of up to $1,871,000 remained available under the December 2010 AMI Agreement.

As of November 30, 2012, aggregate gross proceeds of $151,871,000 remained available under two effective shelf registration statements.

In addition, as of October 31, 2012, we had reserved 24,600,142 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		20,217,891
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		493,247
Total shares of common stock reserved for issuance		24,600,142