12. SELECTED QUARTERLY FINANCIAL DATA (Details) (USD $)	3 Months Ended								12 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 4,254,000	$ 7,039,000	$ 6,139,000	$ 4,251,000	$ 2,065,000	$ 3,281,000	$ 4,242,000	$ 5,655,000	$ 21,683,000	$ 15,233,000	$ 13,492,000
Gross profit	959,000	3,310,000	2,358,000	2,111,000	1,053,000	719,000	436,000	2,422,000	8,738,000	4,630,000	1,206,000
Loss from operations	(8,463,000)	(5,161,000)	(7,057,000)	(7,671,000)	(10,890,000)	(11,093,000)	(12,036,000)	(8,051,000)
Net loss	$ (8,449,000)	$ (4,914,000)	$ (8,753,000)	$ (7,664,000)	$ (10,882,000)	$ (11,090,000)	$ (12,055,000)	$ (8,092,000)	$ (29,780,000)	$ (42,119,000)	$ (34,151,000)
Basic and diluted loss per common share	$ (0.06)	$ (0.04)	$ (0.08)	$ (0.07)	$ (0.10)	$ (0.13)	$ (0.16)	$ (0.11)	$ (0.25)	$ (0.50)	$ (0.56)