Carrying book value of property sold during the year.

No definition available.

Name:	gnbt_BookValueOfPropertySold
Namespace Prefix:	gnbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the expenses incurred for discharge of mortgage on the property with remaining principal amount which was discharged upon sale.

+ References

No definition available.

+ Details

Name:	gnbt_DischargeOfMortgageOnPropertyExpenses
Namespace Prefix:	gnbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item represents investments in mortgage debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

No definition available.

+ Details

Name:	gnbt_MortgageDebtSecurities
Namespace Prefix:	gnbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The maturity date of the mortgage investment.

+ References

No definition available.

+ Details

Name:	gnbt_MortgageInvestmentMaturityDate
Namespace Prefix:	gnbt_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate of investments in mortgage properties.

+ References

No definition available.

+ Details

Name:	gnbt_MortgageInvestmentsInterestRate
Namespace Prefix:	gnbt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount attributable to mortgage on the property with remaining principal amount which was discharged upon sale.

+ References

No definition available.

+ Details

Name:	gnbt_MortgageOnPropertyRemainingPrincipalAmountDischargedUponSale
Namespace Prefix:	gnbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The remaining net proceeds after expenses and discharge of the mortgage.

+ References

No definition available.

+ Details

Name:	gnbt_ProceedsFromSaleOfPropertyRemainingAmount
Namespace Prefix:	gnbt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The difference between the sale price or salvage price and the book value of a property, plant, and equipment asset that was sold or retired during the reporting period. This element refers to the gain (loss).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate amount of income from investments (for example, dividends) not considered a component of the entity's core operations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

+ Details

Name:	us-gaap_InvestmentIncomeNonoperating
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Article 5

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3179-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Income earned by providing the use of assets to an outside party in exchange for a payment or series of payments that is nonoperating in nature.

+ References

+ Details

Name:	us-gaap_RentalIncomeNonoperating
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Income from Assets Held for Investment, net (Details Textual)	1 Months Ended				2 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended			201 Months Ended	210 Months Ended
	Mar. 31, 2013 USD ($)	Nov. 30, 2012 USD ($)	Sep. 30, 2012 USD ($)	Aug. 31, 2011 USD ($)	Apr. 30, 2012 USD ($)	Apr. 30, 2013 USD ($)	Oct. 31, 2012 CAD	Apr. 30, 2012 USD ($)	Apr. 30, 2013 USD ($)	Apr. 30, 2012 USD ($)	Jul. 31, 2012 USD ($)	Jul. 31, 2011 USD ($)	Jul. 31, 2010 USD ($)	Jul. 31, 2012 USD ($)	Apr. 30, 2013 USD ($)
Proceeds from Sale of Real Estate Held-for-investment	$ 256,835
Book Value Of Property Sold	169,566		585,064	1,029,435	1,783,932		577,214
Proceeds from sale of property and equipment			1,579,189	1,669,115	2,865,682		1,640,000		1,762,954	4,614,057	4,953,325	0	0	4,953,325	6,716,279
Loss on disposal of property and equipment	87,682		994,125	639,680	1,081,750				1,036,865	1,793,087	2,027,939	(35,878)	0	1,991,150	3,028,015
Mortgage On Property Remaining Principal Amount Discharged Upon Sale	216,810		480,951	659,288	571,680
Discharge Of Mortgage On Property Expenses	13,000
Proceeds From Sale Of Property Remaining Amount	27,025		1,028,780	1,009,827	2,190,952						249,127
Income from assets held for investment, net (Note 3)						126,701		1,148,526	1,210,567	1,928,850	2,206,216	349,458	206,575	4,334,257	5,544,824
Rental Income From Investment									128,760	207,420
Mortgage Debt Securities		853,119
Mortgage Investments Interest Rate		9.75%
Investment Maturity Date		Nov. 30, 2013
Current maturities of long-term debt (Note 10)						$ 625,793			$ 625,793		$ 1,222,746	$ 1,210,271		$ 1,222,746	$ 625,793