CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
REVENUES:
Contract manufacturing revenue	$ 6,672,000	$ 5,677,000	$ 25,574,000	$ 17,436,000
License revenue	37,000	0	329,000	37,000
Total revenues	6,709,000	5,677,000	25,903,000	17,473,000
COSTS AND EXPENSES:
Cost of contract manufacturing	3,896,000	3,113,000	13,245,000	10,835,000
Research and development	15,156,000	11,261,000	43,264,000	31,465,000
Selling, general and administrative	4,524,000	4,325,000	13,839,000	13,503,000
Total costs and expenses	23,576,000	18,699,000	70,348,000	55,803,000
LOSS FROM OPERATIONS	(16,867,000)	(13,022,000)	(44,445,000)	(38,330,000)
Interest and other income	34,000	29,000	691,000	108,000
Interest and other expense	(14,000)	(1,000)	(14,000)	(1,000)
Total other income (expense), net	20,000	28,000	677,000	107,000
NET LOSS	(16,847,000)	(12,994,000)	(43,768,000)	(38,223,000)
COMPREHENSIVE LOSS	(16,847,000)	(12,994,000)	(43,768,000)	(38,223,000)
Series E preferred stock accumulated dividends	(1,380,000)	(1,033,000)	(3,448,000)	(2,577,000)
NET LOSS ATTRIBUTABLE TO COMMON STOCKHOLDERS	$ (18,227,000)	$ (14,027,000)	$ (47,216,000)	$ (40,800,000)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING - Basic and Diluted	227,389,225	182,519,923	209,549,670	180,562,524
BASIC AND DILUTED LOSS PER COMMON SHARE	$ (.08)	$ (.08)	$ (.23)	$ (.23)