Accounting Policies, by Policy (Policies)	12 Months Ended
May. 31, 2015
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying consolidated financial statements are unaudited and have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, and the Securities and Exchange Commission’s (“SEC”) instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The Company’s interim results are not necessarily indicative of the Company’s expected full year results. These unaudited consolidated financial statements should be read in conjunction with the Company’s audited, consolidated financial statements and related notes for the year ended May 31, 2015, included in the Company’s Annual Report on Form 10-K filed with the SEC on August 21, 2015.
Consolidation, Policy [Policy Text Block]	Basis of Consolidation The consolidated financial statements include the accounts of Immucor and all its subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. There are no other entities controlled by the Company, either directly or indirectly.
New Accounting Pronouncements, Policy [Policy Text Block]	Impact of Recently Issued Accounting Standards – Accounting Standards Not Yet Adopted In July 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-11, Inventory: Simplifying the Measurement of Inventory (“ASU 2015-11”). ASU 2015-11 requires that inventory within the scope of this update be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this update do not apply to inventory that is measured using last-in, first-out (LIFO) or the retail inventory method. The amendments apply to all other inventory, which includes inventory that is measured using first-in, first-out (FIFO) or average cost. This standard is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016, which corresponds to the Company’s first quarter of fiscal year 2018. Early adoption is permitted. The Company is evaluating the effect of the adoption of ASU 2015-11 on its consolidated financial statements. In May 2014, the FASB and International Accounting Standards Board issued their converged standard on revenue recognition, ASU 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). This standard outlines a single comprehensive model for companies to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that revenue is recognized when a customer obtains control of a good or service. A customer obtains control when it has the ability to direct the use of and obtain the benefits from the good or service. Transfer of control is not the same as transfer of risks and rewards, as it is considered in current guidance. The Company will also need to apply new guidance to determine whether revenue should be recognized over time or at a point in time. An amendment was made in July 2015 to change the effective date of this standard from the first interim period within annual reporting periods beginning after December 15, 2016 to December 16, 2017, which corresponds to the Company’s first quarter of fiscal year 2019. No early adoption is permitted under this standard, and it is to be applied either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company is evaluating the effect of the adoption of ASU 2014-09 on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, Interest — Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 changes the presentation of debt issuance costs for term debt in the balance sheet by requiring the debt issuance costs to be presented as a direct deduction from the related debt liability, rather than recorded as an asset. The standard is required to be adopted in interim and annual periods beginning on or after December 15, 2015, which corresponds to the Company’s first quarter of fiscal year 2017. This standard is to be applied retrospectively and early adoption is permitted. The Company is evaluating the effect of the adoption of ASU 2015-03 on its consolidated financial statements

Accounting Policies, by Policy (Policies)

12 Months Ended

May. 31, 2015

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

The accompanying consolidated financial statements are unaudited and have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, and the Securities and Exchange Commission’s (“SEC”) instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The Company’s interim results are not necessarily indicative of the Company’s expected full year results. These unaudited consolidated financial statements should be read in conjunction with the Company’s audited, consolidated financial statements and related notes for the year ended May 31, 2015, included in the Company’s Annual Report on Form 10-K filed with the SEC on August 21, 2015.

Consolidation, Policy [Policy Text Block]

Basis of Consolidation

The consolidated financial statements include the accounts of Immucor and all its subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. There are no other entities controlled by the Company, either directly or indirectly.

New Accounting Pronouncements, Policy [Policy Text Block]

Impact of Recently Issued Accounting Standards –

Accounting Standards Not Yet Adopted

In July 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-11, Inventory: Simplifying the Measurement of Inventory (“ASU 2015-11”). ASU 2015-11 requires that inventory within the scope of this update be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this update do not apply to inventory that is measured using last-in, first-out (LIFO) or the retail inventory method. The amendments apply to all other inventory, which includes inventory that is measured using first-in, first-out (FIFO) or average cost. This standard is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016, which corresponds to the Company’s first quarter of fiscal year 2018. Early adoption is permitted. The Company is evaluating the effect of the adoption of ASU 2015-11 on its consolidated financial statements.

In May 2014, the FASB and International Accounting Standards Board issued their converged standard on revenue recognition, ASU 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). This standard outlines a single comprehensive model for companies to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that revenue is recognized when a customer obtains control of a good or service. A customer obtains control when it has the ability to direct the use of and obtain the benefits from the good or service. Transfer of control is not the same as transfer of risks and rewards, as it is considered in current guidance. The Company will also need to apply new guidance to determine whether revenue should be recognized over time or at a point in time. An amendment was made in July 2015 to change the effective date of this standard from the first interim period within annual reporting periods beginning after December 15, 2016 to December 16, 2017, which corresponds to the Company’s first quarter of fiscal year 2019. No early adoption is permitted under this standard, and it is to be applied either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company is evaluating the effect of the adoption of ASU 2014-09 on its consolidated financial statements.

In April 2015, the FASB issued ASU 2015-03, Interest — Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 changes the presentation of debt issuance costs for term debt in the balance sheet by requiring the debt issuance costs to be presented as a direct deduction from the related debt liability, rather than recorded as an asset. The standard is required to be adopted in interim and annual periods beginning on or after December 15, 2015, which corresponds to the Company’s first quarter of fiscal year 2017. This standard is to be applied retrospectively and early adoption is permitted. The Company is evaluating the effect of the adoption of ASU 2015-03 on its consolidated financial statements