9. SEGMENT REPORTING (Details) (USD $)	3 Months Ended	9 Months Ended
Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Segment Reporting [Abstract]
Contract manufacturing services revenue	$ 5,677,000	$ 3,885,000	$ 17,436,000	$ 15,820,000
Cost of contract manufacturing services	3,113,000us-gaap_CostOfOtherManufacturedProducts	2,416,000us-gaap_CostOfOtherManufacturedProducts	10,835,000us-gaap_CostOfOtherManufacturedProducts	9,281,000us-gaap_CostOfOtherManufacturedProducts
Gross profit	2,564,000us-gaap_GrossProfit	1,469,000us-gaap_GrossProfit	6,601,000us-gaap_GrossProfit	6,539,000us-gaap_GrossProfit
Revenue from products in research and development	0us-gaap_LicensesRevenue	0us-gaap_LicensesRevenue	37,000us-gaap_LicensesRevenue	107,000us-gaap_LicensesRevenue
Research and development expense	(11,261,000)us-gaap_ResearchAndDevelopmentExpense	(6,649,000)us-gaap_ResearchAndDevelopmentExpense	(31,465,000)us-gaap_ResearchAndDevelopmentExpense	(18,910,000)us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative expense	(4,325,000)	(4,563,000)	(13,503,000)	(12,913,000)
Other income, net	28,000us-gaap_OtherOperatingIncomeExpenseNet	19,000us-gaap_OtherOperatingIncomeExpenseNet	107,000us-gaap_OtherOperatingIncomeExpenseNet	63,000us-gaap_OtherOperatingIncomeExpenseNet
Net loss	$ (12,994,000)us-gaap_NetIncomeLoss	$ (9,724,000)us-gaap_NetIncomeLoss	$ (38,223,000)us-gaap_NetIncomeLoss	$ (25,114,000)us-gaap_NetIncomeLoss

Costs incurred in production of other products during the reporting period.

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- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

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- Definition

Revenue earned during the period relating to consideration received from another party for the right to use, but not own, certain of the entity's intangible assets. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark. Licensing fees are generally, but not always, fixed as to amount and not dependent upon the revenue generated by the licensing party. An entity may receive licensing fees for licenses that also generate royalty payments to the entity.

+ References

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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

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-Glossary Net Income

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-Name Accounting Standards Codification

-Topic 944

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-Section S99

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-Subparagraph (SX 210.7-04.19)

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-Subparagraph (SX 210.7-04.22)

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- Definition

The net amount of other operating income and expenses, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operations.

+ References

No definition available.

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- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 20

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-Topic 730

-SubTopic 10

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- Definition

Revenue not otherwise defined in the taxonomy from the sale of manufactured products.

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- Definition

The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 2

-Subparagraph (SX 210.5-03.4)

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-Publisher FASB

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