CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
REVENUES:
Contract manufacturing revenue	$ 9,523,000	$ 6,263,000	$ 18,902,000	$ 11,759,000
License revenue	0	37,000	292,000	37,000
Total revenues	9,523,000	6,300,000	19,194,000	11,796,000
COSTS AND EXPENSES:
Cost of contract manufacturing	4,741,000	4,139,000	9,349,000	7,722,000
Research and development	14,190,000	10,003,000	28,108,000	20,204,000
Selling, general and administrative	4,416,000	4,295,000	9,315,000	9,178,000
Total costs and expenses	23,347,000	18,437,000	46,772,000	37,104,000
LOSS FROM OPERATIONS	(13,824,000)	(12,137,000)	(27,578,000)	(25,308,000)
Interest and other income	626,000	37,000	657,000	79,000
NET LOSS	(13,198,000)	(12,100,000)	(26,921,000)	(25,229,000)
COMPREHENSIVE LOSS	(13,198,000)	(12,100,000)	(26,921,000)	(25,229,000)
Series E preferred stock accumulated dividends	(1,380,000)	(1,031,000)	(2,413,000)	(1,802,000)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (14,578,000)	$ (13,131,000)	$ (29,334,000)	$ (27,031,000)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING - Basic and Diluted	203,942,411	179,962,275	200,629,892	179,540,265
BASIC AND DILUTED LOSS PER COMMON SHARE	$ (.07)	$ (.07)	$ (.15)	$ (.15)