11. SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($)		3 Months Ended																12 Months Ended
		Apr. 30, 2018		Jan. 31, 2018		Oct. 31, 2017		Jul. 31, 2017		Apr. 30, 2017		Jan. 31, 2017		Oct. 31, 2016		Jul. 31, 2016		Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Contract manufacturing revenue		$ 6,943,000		$ 6,819,000		$ 12,782,000		$ 27,077,000		$ 17,904,000		$ 10,747,000		$ 23,370,000		$ 5,609,000
Gross profit		(1,961,000)	[1]	(4,132,000)	[1]	(3,460,000)	[1]	6,629,000	[1]	6,122,000		2,773,000		7,929,000		2,547,000		$ (2,924,000)	$ 19,371,000	$ 21,391,000
Income (loss) from continuing operations		(6,134,000)		(8,928,000)		(8,301,000)		2,800,000		1,677,000		(1,569,000)		3,303,000		(2,018,000)
Income (loss) from discontinued operations		9,154,000	[2],[3]	(2,076,000)	[2],[3]	(4,323,000)	[2],[3]	(4,005,000)	[2],[3]	(6,949,000)	[2]	(6,205,000)	[2]	(7,359,000)	[2]	(9,039,000)	[2]	(1,250,000)	(29,552,000)	(59,249,000)
Net income (loss)		3,020,000		(11,004,000)		(12,624,000)		(1,205,000)		(5,272,000)		(7,774,000)		(4,056,000)		(11,057,000)		(21,813,000)	(28,159,000)	(55,652,000)
Series E preferred stock accumulated dividends	[4]	(1,442,000)		(1,442,000)		(1,442,000)		(1,442,000)		(1,442,000)		(1,442,000)		(1,442,000)		(1,380,000)
Net income (loss) attributable to common stockholders		$ 1,578,000		$ (12,446,000)		$ (14,066,000)		$ (2,647,000)		$ (6,714,000)		$ (9,216,000)		$ (5,498,000)		$ (12,437,000)		$ (26,499,000)	$ (32,799,000)	$ (60,136,000)
Basic and diluted weighted average common shares outstanding		53,360,424		45,225,804		45,097,474		44,773,727		42,141,720		37,258,794		34,973,681		34,227,870		47,063,020	37,109,493	30,895,089
Basic and diluted net loss per common share attributable to common stockholders - Continuing operations		$ (0.14)	[5]	$ (0.23)	[5]	$ (0.21)	[5]	$ 0.03	[5]	$ 0.01	[5]	$ (0.08)	[5]	$ 0.05	[5]	$ (0.10)	[5]	$ (0.53)	$ (0.09)	$ (0.03)
Basic and diluted net loss per common share attributable to common stockholders - Discontinued operations		0.17	[5]	(0.05)	[5]	(0.10)	[5]	(0.09)	[5]	(0.17)	[5]	(0.17)	[5]	(0.21)	[5]	(0.26)	[5]	(0.03)	(0.79)	(1.92)
Net loss per share attributable to common stockholders		$ 0.03		$ (0.28)		$ (0.31)		$ (0.06)		$ (0.16)		$ (0.25)		$ (0.16)		$ (0.36)		$ (0.56)	$ (0.88)	$ (1.95)

[1] Gross profit (loss) for the first, second, third, and fourth quarters of fiscal year 2018 includes idle capacity costs of $900,000, $4,938,000, $5,344,000 and $2,784,000, respectively, which amounts were expensed directly to cost of contract manufacturing. No idle capacity costs were incurred during the same prior year periods.

[2] As of January 31, 2018, our research and development segment met all the conditions required in order to be classified as a discontinued operation (Note 2). Accordingly, the operating results of our research and development segment are reported as income (loss) from discontinued operations for all periods presented.

[3] Income from discontinued operations for the quarter ended April 30, 2018 includes a gain on sale of research and development assets of $8,000,000 (Note 9).

[4] Series E preferred stock accumulated dividends include dividends declared for the period (regardless of whether or not the dividends have been paid) and dividends accumulated for the period (regardless of whether or not the dividends have been declared).

[5] Basic and diluted net income (loss) per common share attributable to common stockholders calculations for each of the quarters are based on the basic and diluted weighted average common shares outstanding for each period. As such, the sum of the quarters may not necessarily equal the basic and diluted net income (loss) per common share amount for the fiscal year.