11. SEGMENT REPORTING (Details) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Segment Reporting Details
Contract manufacturing services revenue	$ 6,961,000	$ 3,203,000	$ 17,157,000	$ 12,796,000
Cost of contract manufacturing services	3,651,000	2,484,000	9,378,000	9,219,000
Gross profit	3,310,000	719,000	7,779,000	3,577,000
Revenue from products in research and development	78,000	78,000	272,000	372,000
Research and development expense	(5,437,000)	(9,180,000)	(18,471,000)	(26,758,000)
Selling, general and administrative expense	(3,112,000)	(2,710,000)	(9,469,000)	(8,371,000)
Other income (expense), net	247,000	3,000	254,000	(57,000)
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)