7. EQUITY COMPENSATION PLANS (Tables)

3 Months Ended

Jul. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock option transaction activity

Stock Options	Shares			Weighted Average Exercisable Price
Outstanding, May 1, 2015		20,708,672			$  1.54
Granted		3,523,911			$  1.31
Exercised		(99,091	)		$  0.94
Canceled or expired		(266,239	)		$  1.70
Outstanding, July 31, 2015		23,867,253			$  1.51

Share-based compensation expense

	Three Months Ended July 31,
	2015		2014
Cost of contract manufacturing	$	13,000	$	24,000
Research and development		471,000		743,000
Selling, general and administrative		699,000		1,009,000
Total share-based compensation expense	$	1,183,000	$	1,776,000
Share-based compensation from:
Stock options	$	1,124,000	$	1,697,000
Employee stock purchase plan		59,000		79,000
	$	1,183,000	$	1,776,000