9. SEGMENT REPORTING (Details) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Segment Reporting [Abstract]
Contract manufacturing services revenue	$ 23,370,000	$ 9,523,000	$ 28,979,000	$ 18,902,000
Cost of contract manufacturing services	15,441,000	4,741,000	18,503,000	9,349,000
Gross profit	7,929,000	4,782,000	10,476,000	9,553,000
Revenue from products in research and development	0	0	0	292,000
Research and development expense	(7,022,000)	(14,190,000)	(15,591,000)	(28,108,000)
Selling, general and administrative expense	(4,984,000)	(4,416,000)	(10,044,000)	(9,315,000)
Interest and other income	21,000	626,000	46,000	657,000
Net loss	$ (4,056,000)	$ (13,198,000)	$ (15,113,000)	$ (26,921,000)