CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
REVENUES:
Contract manufacturing revenue	$ 5,677,000	$ 3,885,000	$ 17,436,000	$ 15,820,000
License revenue	0	0	37,000	107,000
Total revenues	5,677,000	3,885,000	17,473,000	15,927,000
COSTS AND EXPENSES:
Cost of contract manufacturing	3,113,000	2,416,000	10,835,000	9,281,000
Research and development	11,261,000	6,649,000	31,465,000	18,910,000
Selling, general and administrative	4,325,000	4,563,000	13,503,000	12,913,000
Total costs and expenses	18,699,000	13,628,000	55,803,000	41,104,000
LOSS FROM OPERATIONS	(13,022,000)	(9,743,000)	(38,330,000)	(25,177,000)
OTHER INCOME (EXPENSE):
Interest and other income	29,000	23,000	108,000	68,000
Interest and other expense	(1,000)	(4,000)	(1,000)	(5,000)
NET LOSS	(12,994,000)	(9,724,000)	(38,223,000)	(25,114,000)
COMPREHENSIVE LOSS	(12,994,000)	(9,724,000)	(38,223,000)	(25,114,000)
Series E preferred stock accumulated dividends	(1,033,000)	0	(2,577,000)	0
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (14,027,000)	$ (9,724,000)	$ (40,800,000)	$ (25,114,000)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING - Basic and Diluted	182,519,923	163,223,767	180,562,524	156,521,874
BASIC AND DILUTED LOSS PER COMMON SHARE	$ (0.08)	$ (0.06)	$ (0.23)	$ (0.16)