9. EQUITY COMPENSATION PLANS

6 Months Ended

Oct. 31, 2012

Equity Compensation Plans

9. Equity Compensation Plans

Stock Incentive Plans

We currently maintain seven stock incentive plans referred to as the 2011 Plan, the 2010 Plan, the 2009 Plan, the 2005 Plan, the 2003 Plan, the 2002 Plan, and the 1996 Plan (collectively referred to as the “Stock Plans”). On October 18, 2012, our stockholders approved an amendment to our 2011 Plan to increase the number of shares of our common stock reserved for issuance from 3,500,000 to 11,500,000 shares.

As of October 31, 2012, we had an aggregate of 20,217,891 shares of common stock reserved for issuance under the Stock Plans, of which, 11,631,587 shares were subject to outstanding options and 8,586,304 shares were available for future grants of share-based awards.

The following summarizes our stock option transaction activity for the six months ended October 31, 2012:

Stock Options	Shares		Weighted Average Exercisable Price
Outstanding, May 1, 2012	7,531,651		$2.90
Granted	4,431,477		$0.58
Exercised	(30,093	)	$1.16
Canceled or expired	(301,448	)	$1.60
Outstanding, October 31, 2012	11,631,587		$2.06

Employee Stock Purchase Plan

We have reserved a total of 5,000,000 shares of common stock to be purchased under our 2010 Employee Stock Purchase Plan (the “2010 ESPP”), of which 3,889,004 shares of common stock remain available for purchase as of October 31, 2012. Under the 2010 ESPP, we will sell shares to participants at a price equal to the lesser of 85% of the fair market value of stock at the (i) beginning of a six-month offering period or (ii) at the end of the six-month offering period. The 2010 ESPP provides for two six-month offering periods each year; the first offering period will begin on the first trading day on or after each November 1; the second offering period will begin on the first trading day on or after each May 1. During the six months ended October 31, 2012, 548,111 shares of common stock were purchased under the 2010 ESPP at a purchase price per share of $0.39.

Share-Based Compensation

Total share-based compensation expense for the three and six-month periods ended October 31, 2012 and 2011 are included in the accompanying interim unaudited condensed consolidated statements of operations and comprehensive loss as follows:

	Three Months Ended   October 31,				Six Months Ended October 31,
	2012		2011		2012		2011
Cost of contract manufacturing	$	9,000	$	2,000	$	18,000	$	5,000
Research and development		289,000		302,000		612,000		621,000
Selling, general and administrative		331,000		491,000		661,000		1,053,000
Total	$	629,000	$	795,000	$	1,291,000	$	1,679,000
Share-based compensation from:
Stock options	$	584,000	$	783,000	$	1,199,000	$	1,636,000
Employee stock purchase plan		45,000		12,000		92,000		43,000
	$	629,000	$	795,000	$	1,291,000	$	1,679,000

As of October 31, 2012, the total estimated unrecognized compensation cost related to non-vested stock options was $3,204,000. This cost is expected to be recognized over a weighted average vesting period of 1.66 years based on current assumptions.