7. EQUITY COMPENSATION PLANS (Tables)

12 Months Ended

Apr. 30, 2013

Equity Compensation Plans Tables

Fair value valuation assumptions

The fair value of stock options on the date of grant and the weighted-average assumptions used to estimate the fair value of the stock options using the Black-Scholes option valuation model for fiscal years ended April 30, 2013, 2012 and 2011, were as follows:

	Year Ended April 30,
	2013	2012	2011
Risk-free interest rate	0.96%	1.44%	2.09%
Expected life (in years)	5.85	5.92	6.00
Expected volatility	95.87%	74.08%	73.42%
Expected dividend yield	-	-	-

The weighted average grant date fair value of purchase rights under the 2010 ESPP during fiscal years ended April 30, 2013, 2012 and 2011 was $0.40, $0.46 and $0.52, respectively, based on the following Black-Scholes option valuation model inputs:

	Year Ended April 30,
	2013	2012	2011
Risk-free interest rate	0.15%	0.06%	0.15%
Expected life (in years)	0.50	0.50	0.50
Expected volatility	167.36%	67.96%	82.72%
Expected dividend yield	-	-	-

Stock Options

The following summarizes our stock option transaction activity for fiscal year ended April 30, 2013:

Stock Options	Shares			Weighted Average Exercisable Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (1)
Outstanding, May 1, 2012		7,531,651		$	2.90
Granted		8,677,208		$	0.88
Exercised		(118,555	)	$	0.83
Canceled or expired		(803,096	)	$	1.58
Outstanding, April 30, 2013		15,287,208		$	1.84		8.07	$	5,294,000
Exercisable and expected to vest		15,086,905		$	1.85		8.05	$	5,228,000
Exercisable, April 30, 2013		7,434,607		$	2.67		6.86	$	1,811,000

Share-based compensation expense

Total share-based compensation expense related to share-based awards issued under our equity compensation plans for the fiscal years ended April 30, 2013, 2012 and 2011 was comprised of the following:

	2013		2012		2011
Cost of contract manufacturing	$	89,000	$	12,000	$	8,000
Research and development		1,646,000		1,018,000		1,134,000
Selling, general and administrative		1,700,000		1,739,000		1,695,000
Total share-based compensation expense	$	3,435,000	$	2,769,000	$	2,837,000
Share-based compensation from:
Stock options	$	3,039,000	$	2,673,000	$	2,598,000
Restricted stock awards		–		–		185,000
Employee stock purchase plan		396,000		96,000		54,000
	$	3,435,000	$	2,769,000	$	2,837,000