Note 16 - Condensed Consolidating Financial Information of Guarantor Subsidiaries - Condensed Consolidating Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
Feb. 28, 2017	Feb. 29, 2016
Net cash (used in) provided by operating activities	$ (6,499)	$ 6,841
Net cash used in investing activities	(8,318)	(12,650)
Net cash provided by (used in) financing activities	14,498	(482)
Effect of exchange rate changes on cash and cash equivalents	91	118
Increase (decrease) in cash and cash equivalents	(228)	(6,173)
Cash and cash equivalents at beginning of period	10,263	18,363
Cash and cash equivalents at end of period	10,035	12,190
Reportable Legal Entities [Member] \| Parent Company [Member]
Net cash (used in) provided by operating activities	(5,034)	10,666
Net cash used in investing activities	(2,414)	(8,860)
Net cash provided by (used in) financing activities	7,345	(6,475)
Effect of exchange rate changes on cash and cash equivalents	140	269
Increase (decrease) in cash and cash equivalents	37	(4,400)
Cash and cash equivalents at beginning of period	4,058	7,080
Cash and cash equivalents at end of period	4,095	2,680
Reportable Legal Entities [Member] \| Guarantor Subsidiaries [Member]
Net cash (used in) provided by operating activities	1,337	1,423
Net cash used in investing activities	(1,196)	(1,671)
Net cash provided by (used in) financing activities	(147)	(7)
Effect of exchange rate changes on cash and cash equivalents
Increase (decrease) in cash and cash equivalents	(6)	(255)
Cash and cash equivalents at beginning of period	(187)	(263)
Cash and cash equivalents at end of period	(193)	(518)
Reportable Legal Entities [Member] \| Non-Guarantor Subsidiaries [Member]
Net cash (used in) provided by operating activities	9,187	(1,600)
Net cash used in investing activities	(663)	3,890
Net cash provided by (used in) financing activities	(8,744)	(3,517)
Effect of exchange rate changes on cash and cash equivalents	(340)	(291)
Increase (decrease) in cash and cash equivalents	(560)	(1,518)
Cash and cash equivalents at beginning of period	6,356	11,546
Cash and cash equivalents at end of period	5,796	10,028
Reportable Legal Entities [Member] \| Immucor Inc and Subsidiaries [Member]
Net cash (used in) provided by operating activities	358
Net cash used in investing activities	(8,176)
Net cash provided by (used in) financing activities	7,198
Effect of exchange rate changes on cash and cash equivalents	91
Increase (decrease) in cash and cash equivalents	(529)
Cash and cash equivalents at beginning of period	10,227
Cash and cash equivalents at end of period	9,698
Reportable Legal Entities [Member] \| VIE and VIE Eliminations [Member]
Net cash (used in) provided by operating activities	(6,857)
Net cash used in investing activities	(142)
Net cash provided by (used in) financing activities	7,300
Effect of exchange rate changes on cash and cash equivalents
Increase (decrease) in cash and cash equivalents	301
Cash and cash equivalents at beginning of period	36
Cash and cash equivalents at end of period	337
Consolidation, Eliminations [Member]
Net cash (used in) provided by operating activities	(5,132)	(3,648)
Net cash used in investing activities	(3,903)	(6,009)
Net cash provided by (used in) financing activities	8,744	9,517
Effect of exchange rate changes on cash and cash equivalents	291	140
Increase (decrease) in cash and cash equivalents
Cash and cash equivalents at beginning of period
Cash and cash equivalents at end of period

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6507016

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Amount of cash inflow (outflow) of investing activities, excluding discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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