Note 16 - Condensed Consolidating Financial Information of Guarantor Subsidiaries - Consolidating Statements of Operations (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
		Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016	May 31, 2016
Net sales		$ 93,964	$ 88,893	$ 286,233	$ 281,854
Cost of sales (*)	[1],[2]	35,318	34,130	109,949	106,660
Gross profit		58,646	54,763	176,284	175,194
Research and development		8,828	6,910	26,625	20,500
Selling and marketing		13,528	13,251	44,019	42,057
Distribution		4,083	4,155	12,648	12,969
General and administrative		10,046	11,779	32,111	33,133
Amortization expense		14,109	13,575	42,416	40,745
Total operating expenses		50,594	49,670	157,819	149,404
Income (loss) from operations		8,052	5,093	18,465	25,790
Interest income		1	48	9	132
Interest expense		(22,981)	(22,329)	(69,203)	(67,275)
Other, net		(106)	(317)	(660)	(366)
Total non-operating net expense		(23,086)	(22,598)	(69,854)	(67,509)
(Loss) income before income taxes		(15,034)	(17,505)	(51,389)	(41,719)
(Benefit) provision for income taxes		(5,616)	(8,845)	(19,112)	(14,046)
Net (loss) income before earnings of consolidated subsidaries		(9,418)	(8,660)	(32,277)	(27,673)
Net (loss) income of consolidated subsidiaries
Net (loss) income		(9,418)	(8,660)	(32,277)	(27,673)	$ (43,767)
Net loss attributable to noncontrolling interest		(1,668)	(237)	(4,654)	(237)
Net (loss) income attributable to shareholders of Immucor, Inc.		(7,750)	(8,423)	(27,623)	(27,436)
Consolidation, Eliminations [Member]
Net sales		(19,234)	(15,678)	(54,218)	(49,483)
Cost of sales (*)	[2]	(19,234)	(15,679)	(54,218)	(49,483)
Gross profit			1
Research and development			(253)		(253)
Selling and marketing
Distribution
General and administrative			(27)		(27)
Amortization expense
Total operating expenses			(280)		(280)
Income (loss) from operations			281		280
Interest income		(107)	(111)	(299)	(165)
Interest expense		107	111	299	165
Other, net			(280)		(280)
Total non-operating net expense			(280)		(280)
(Loss) income before income taxes			1
(Benefit) provision for income taxes
Net (loss) income before earnings of consolidated subsidaries			1
Net (loss) income of consolidated subsidiaries		(181)	4,288	7,462	6,423
Net (loss) income		(181)	4,289	7,462	6,423
Net loss attributable to noncontrolling interest
Net (loss) income attributable to shareholders of Immucor, Inc.		(181)	4,289	7,462	6,423
Parent Company [Member] | Reportable Legal Entities [Member]
Net sales		61,765	57,913	184,721	185,196
Cost of sales (*)	[2]	22,155	20,150	64,628	62,491
Gross profit		39,610	37,763	120,093	122,705
Research and development		3,572	2,970	10,910	8,919
Selling and marketing		6,684	5,745	22,275	18,820
Distribution		2,100	2,288	6,559	7,224
General and administrative		6,507	8,588	21,825	22,683
Amortization expense		11,970	11,972	35,912	35,916
Total operating expenses		30,833	31,563	97,481	93,562
Income (loss) from operations		8,777	6,200	22,612	29,143
Interest income		241	105	628	183
Interest expense		(22,136)	(22,253)	(66,800)	(66,997)
Other, net		1,014	4,086	7,845	5,046
Total non-operating net expense		(20,881)	(18,062)	(58,327)	(61,768)
(Loss) income before income taxes		(12,104)	(11,862)	(35,715)	(32,625)
(Benefit) provision for income taxes		(4,173)	(7,727)	(15,554)	(11,612)
Net (loss) income before earnings of consolidated subsidaries		(7,931)	(4,135)	(20,161)	(21,013)
Net (loss) income of consolidated subsidiaries		181	(4,288)	(7,462)	(6,423)
Net (loss) income		(7,750)	(8,423)	(27,623)	(27,436)
Net loss attributable to noncontrolling interest
Net (loss) income attributable to shareholders of Immucor, Inc.		(7,750)	(8,423)	(27,623)	(27,436)
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Net sales		16,805	14,370	48,473	43,423
Cost of sales (*)	[2]	10,155	8,527	29,370	26,605
Gross profit		6,650	5,843	19,103	16,818
Research and development		3,960	3,785	12,330	11,088
Selling and marketing		1,865	2,242	6,133	7,745
Distribution		296	333	942	1,056
General and administrative		1,144	1,289	3,828	4,117
Amortization expense		1,629	1,082	4,930	3,238
Total operating expenses		8,894	8,731	28,163	27,244
Income (loss) from operations		(2,244)	(2,888)	(9,060)	(10,426)
Interest income				5
Interest expense		(889)	(118)	(2,596)	(350)
Other, net		403	92	1,282	(154)
Total non-operating net expense		(486)	(26)	(1,309)	(504)
(Loss) income before income taxes		(2,730)	(2,914)	(10,369)	(10,930)
(Benefit) provision for income taxes		(995)	(1,045)	(3,093)	(3,833)
Net (loss) income before earnings of consolidated subsidaries		(1,735)	(1,869)	(7,276)	(7,097)
Net (loss) income of consolidated subsidiaries
Net (loss) income		(1,735)	(1,869)	(7,276)	(7,097)
Net loss attributable to noncontrolling interest
Net (loss) income attributable to shareholders of Immucor, Inc.		(1,735)	(1,869)	(7,276)	(7,097)
Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Net sales		34,628	32,288	107,257	102,718
Cost of sales (*)	[2]	22,242	21,132	70,169	67,047
Gross profit		12,386	11,156	37,088	35,671
Research and development		240	408	563	746
Selling and marketing		4,979	5,264	15,611	15,492
Distribution		1,687	1,534	5,147	4,689
General and administrative		2,380	1,929	6,391	6,360
Amortization expense		508	521	1,569	1,591
Total operating expenses		9,794	9,656	29,281	28,878
Income (loss) from operations		2,592	1,500	7,807	6,793
Interest income		69	54	263	114
Interest expense		(63)	(69)	(106)	(93)
Other, net		(219)	(4,215)	(6,078)	(4,978)
Total non-operating net expense		(213)	(4,230)	(5,921)	(4,957)
(Loss) income before income taxes		2,379	(2,730)	1,886	1,836
(Benefit) provision for income taxes		463	(73)	2,072	1,399
Net (loss) income before earnings of consolidated subsidaries		1,916	(2,657)	(186)	437
Net (loss) income of consolidated subsidiaries
Net (loss) income		1,916	(2,657)	(186)	437
Net loss attributable to noncontrolling interest			(237)		(237)
Net (loss) income attributable to shareholders of Immucor, Inc.		1,916	$ (2,420)	(186)	$ 674
Immucor Inc and Subsidiaries [Member] | Reportable Legal Entities [Member]
Net sales		93,964		286,233
Cost of sales (*)	[2]	35,318		109,949
Gross profit		58,646		176,284
Research and development		7,772		23,803
Selling and marketing		13,528		44,019
Distribution		4,083		12,648
General and administrative		10,031		32,044
Amortization expense		14,107		42,411
Total operating expenses		49,521		154,925
Income (loss) from operations		9,125		21,359
Interest income		203		597
Interest expense		(22,981)		(69,203)
Other, net		1,198		3,049
Total non-operating net expense		(21,580)		(65,557)
(Loss) income before income taxes		(12,455)		(44,198)
(Benefit) provision for income taxes		(4,705)		(16,575)
Net (loss) income before earnings of consolidated subsidaries		(7,750)		(27,623)
Net (loss) income of consolidated subsidiaries
Net (loss) income		(7,750)		(27,623)
Net loss attributable to noncontrolling interest
Net (loss) income attributable to shareholders of Immucor, Inc.		(7,750)		(27,623)
VIE and VIE Eliminations [Member] | Reportable Legal Entities [Member]
Net sales
Cost of sales (*)	[2]
Gross profit
Research and development		1,056		2,822
Selling and marketing
Distribution
General and administrative		15		67
Amortization expense		2		5
Total operating expenses		1,073		2,894
Income (loss) from operations		(1,073)		(2,894)
Interest income		(202)		(588)
Interest expense
Other, net		(1,304)		(3,709)
Total non-operating net expense		(1,506)		(4,297)
(Loss) income before income taxes		(2,579)		(7,191)
(Benefit) provision for income taxes		(911)		(2,537)
Net (loss) income before earnings of consolidated subsidaries		(1,668)		(4,654)
Net (loss) income of consolidated subsidiaries
Net (loss) income		(1,668)		(4,654)
Net loss attributable to noncontrolling interest		(1,668)		(4,654)
Net (loss) income attributable to shareholders of Immucor, Inc.

[1] Cost of sales is exclusive of amortization expense which is shown separately within operating expenses.

[2] Cost of sales is exclusive of amortization expense which is shown separately within operating expenses.