Commitments and Contingencies (Details Narrative) - USD ($)					1 Months Ended											3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 07, 2021	May 06, 2020	Dec. 02, 2019	Dec. 03, 2018	May 17, 2021	Mar. 25, 2021	Feb. 19, 2021	Sep. 18, 2020	Jul. 31, 2020	Feb. 18, 2020	Nov. 25, 2019	Nov. 24, 2019	Nov. 22, 2019	Aug. 22, 2017	Dec. 31, 2011	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020	Nov. 16, 2012	Apr. 20, 2021	May 04, 2020	Apr. 24, 2020	Dec. 02, 2018	Oct. 26, 2018
Settlement of litigation								$ 200,000
Commitments and Contingencies														The letter from AEXG counsel claimed that Generex’ acceptance of $3,000,000 in financing from Pharma Trials, LLC, in March 2017, violated the provisions of the MOU prohibiting Generex from seeking other financing, with certain exceptions, for a period of 60 days after execution of the MOU. AEXG has demanded at least $210,000 in cash and 84,000 warrants for Generex stock convertible at $2.50 per share, for attorney’s fees and costs.
Litigation awards for damages				$ 315,695				384,771
Litigation awards, exercisable shares																							84,000	84,000
Exercise price																							$ 2.50	$ 2.50
Note amount																									$ 682,000
Accrued Liquidated damages								210,000
Accrued claim																$ 2,752,235		$ 2,752,235
Legal fees								93,304
Research and development																1,202,835	$ 332,029	3,931,142	$ 1,270,600
Payable to foundation for services									$ 1,315,817							1,315,817		1,315,817
Interest payable to foundation									$ 3,911,141							4,660,634		4,660,634
Interest accrued payable to foundation																		261,069	749,493
Arbitration fees								12,393
Arbitration expenses								3,313
Proceeds from refundable advances																		2,000,000
Bonus																7,060,417		$ 7,060,417
Pre-judgment interest								$ 65,762
Bonus compensation description																		Company awarded executives and employees bonus compensation of $7,060,417 to be paid in approximately $1 million in cash and $6 million in stock.
Accrued claim																4,595,899		$ 4,595,899
Interest expense																1,051,624	$ 1,506,103	2,658,740	5,453,268
Iliad [Member]
Shares issued for litigation settlement									3,499,415
Shares issued for litigation settlement, value									$ 1,459,676
Stock issued for debt conversion, shares		3,499,415
Stock issued for debt conversion, value		$ 1,459,676
AEXG [Member]
Litigation awards for damages	$ 3,300,000
Legal fees	$ 41,730
NDS
Accrued claim																3,416,695		3,416,695
KSKZ Management [Member]
Consulting fees			$ 3,450,000
Damages										$ 2,475,000
Discover Growth Fund [Member]
Litigation awards for damages																		2,200,000
Accrued claim																2,500,000		2,500,000				$ 2,200,000
Legal fees																		53,312
Payment for legal settlement							$ 2,253,312
ALTuCELL [Member]
Common stock description													Under the SPA, in exchange for the ALTuCELL Stock, Generex will issue to ALTuCELL 2,240,000 shares of Generex common stock with an attributed value of $4 million to be issued at the market price of the day at closing, but no less than $0.89 per share. The Company will also pay $2.5 million in cash of which $212,000 has already been paid. In addition to stock and cash at closing, Generex has agreed to pay up to an aggregate of $3,500,000 to ALTuCELL upon ALTuCELL’s attainment of certain milestones.
Advanced to related party																212,000		212,000
Damages for Unpaid Invoices
Value of damages sought															$ 429,000
Lawsuit filing date															31-Dec-11
Name of Plaintiff															Vendor
Settlement of litigation																				$ 125,000
Interest per annum, failure to pay settlement															3.00%
Fixed cost per annum, failure to pay settlement																		25,000
Breach of contract and detinue
Counterclaim proceeding															$ 200,000
Quantum [Member]
Payable to foundation for services																					$ 102,260
Alternative Execution Group [Member]
Memorandum of Understanding description				The petition includes a demand of $3,300,360 as the value of the warrants. The arbitrator did not award the specific amount of $3.5 million, but only liquidated damages in the amount of $210,000 and the value of 84,000 warrants “as of today” (the date of the award) plus attorney’s fees, certain costs, prejudgment and post-judgment interest (which continues to run on a daily basis) and arbitration fees.
Olaregen
Stock Purchase Agreement description												Company amended the Stock Purchase Agreement with Olaregen. The Company was obligated to pay in full $11,600,000 to Olaregen by November 30, 2019, in connection with the purchase of Olaregen capital stock (the “Olaregen Note”). Effective November 24, 2019, the deadline was extended to January 31, 2020.
Regentys
Stock Purchase Agreement description											Company amended the Stock Purchase Agreement with Regentys originally on January 7, 2019. Effective November 25, 2019, the remaining three payments of $2,039,001, $2,000,000, and $3,000,000 were all payable on or before December 30, 2019. The Company is negotiating the terms of a new extension and there has been no demand for payment at this time.
COVID Agreement [Member]
Income taxes received																4,500,000		4,500,000
Settlement Agreement [Member] | Alpha [Member]
Payment for legal settlement					$ 750,000	$ 750,000
Accrued interest						$ 370,553
Clinical trial agreement [Member] | NSABP [Member]
Accrued claim																1,120,637		1,120,637
Research and development																		80,000	$ 251,459
Clinical trial agreement [Member] | Cellular Technology Limited [Member]
Research and development																$ 149,895		$ 1,265,835