CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
REVENUES:
Contract manufacturing revenue	$ 6,961,000	$ 3,203,000	$ 17,157,000	$ 12,796,000
License revenue	78,000	78,000	272,000	372,000
Total revenues	7,039,000	3,281,000	17,429,000	13,168,000
COSTS AND EXPENSES:
Cost of contract manufacturing	3,651,000	2,484,000	9,378,000	9,219,000
Research and development	5,437,000	9,180,000	18,471,000	26,758,000
Selling, general and administrative	3,112,000	2,710,000	9,469,000	8,371,000
Total costs and expenses	12,200,000	14,374,000	37,318,000	44,348,000
LOSS FROM OPERATIONS	(5,161,000)	(11,093,000)	(19,889,000)	(31,180,000)
OTHER INCOME (EXPENSE):
Interest and other income	255,000	9,000	307,000	31,000
Interest and other expense	(8,000)	(6,000)	(53,000)	(88,000)
Loss on early extinguishment of debt	0	0	(1,696,000)	0
NET LOSS	(4,914,000)	(11,090,000)	(21,331,000)	(31,237,000)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING Basic and Diluted (in Shares)	131,489,994	87,149,770	114,726,569	78,443,114
BASIC AND DILUTED LOSS PER COMMON SHARE (in Dollars per share)	$ (0.04)	$ (0.13)	$ (0.19)	$ (0.40)
COMPREHENSIVE LOSS	$ (4,914,000)	$ (11,090,000)	$ (21,331,000)	$ (31,237,000)