Note 16 - Condensed Consolidating Financial Information Of Guarantor Subsidiary (Detail) - Condensed Consolidating Statements of Operations (USD $)	3 Months Ended				6 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Aug. 19, 2011	Nov. 30, 2011	Nov. 30, 2012
NET SALES	$ 82,056,000	$ 83,035,000	$ 74,910,000	$ 94,425,000	$ 167,210,000
COST OF SALES (exclusive of amortization shown separately below)	27,166,000	42,426,000	22,955,000	49,582,000	54,267,000
GROSS MARGIN	54,890,000	40,609,000	51,955,000	44,843,000	112,943,000
OPERATING EXPENSES:
Research and development	4,537,000	5,146,000	4,895,000	5,769,000	9,422,000
Selling and marketing	12,941,000	9,933,000	10,510,000	11,045,000	25,162,000
Distribution	4,721,000	4,576,000	3,952,000	5,225,000	9,229,000
General and administrative	10,813,000	11,205,000	38,175,000	11,959,000	20,929,000
Amortization of intangibles	12,404,000	12,462,000	931,000	14,110,000	24,785,000
Certain litigation expenses		22,000,000		22,000,000
Loss on disposition of fixed assets	(1,175,000)				(1,175,000)
Total operating expenses	46,591,000	65,322,000	58,463,000	70,108,000	90,702,000
INCOME (LOSS) FROM OPERATIONS	8,299,000	(24,713,000)	(6,508,000)	(25,265,000)	22,241,000
NON-OPERATING INCOME (EXPENSE):
Interest income	7,000	6,000	142,000	6,000	10,000
Interest expense	22,251,000	24,850,000	0	28,243,000	46,739,000
Loss on extinguishment of debt					(6,686,000)
Other, net	(242,000)	671,000	2,673,000	660,000	(122,000)
Total non-operating income (expense)	(22,486,000)	(24,173,000)	2,815,000	(27,577,000)	(53,537,000)
INCOME (LOSS) BEFORE INCOME TAXES	(14,187,000)	(48,886,000)	(3,693,000)	(52,842,000)	(31,296,000)
PROVISION (BENEFIT) FOR INCOME TAXES	(3,788,000)	(18,707,000)	2,681,000	(20,221,000)	(10,262,000)
NET INCOME (LOSS) BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(10,399,000)	(30,179,000)	(6,374,000)	(32,621,000)	(21,034,000)
NET INCOME (LOSS)	(10,399,000)	(30,179,000)	(6,374,000)	(32,621,000)	(21,034,000)
Immucor Inc [Member]
NET SALES	61,454,000	59,202,000	55,063,000	66,921,000	125,958,000
COST OF SALES (exclusive of amortization shown separately below)	20,036,000	27,826,000	17,070,000	32,659,000	40,063,000
GROSS MARGIN	41,418,000	31,376,000	37,993,000	34,262,000	85,895,000
OPERATING EXPENSES:
Research and development	3,075,000	2,099,000	2,390,000	2,387,000	6,283,000
Selling and marketing	6,744,000	4,979,000	5,321,000	5,556,000	13,702,000
Distribution	2,935,000	2,756,000	2,331,000	3,156,000	5,810,000
General and administrative	8,080,000	7,847,000	33,903,000	8,302,000	15,629,000
Amortization of intangibles	11,771,000	11,251,000	117,000	12,731,000	23,542,000
Certain litigation expenses		22,000,000		22,000,000
Loss on disposition of fixed assets	1,175,000				1,175,000
Total operating expenses	33,780,000	50,932,000	44,062,000	54,132,000	66,141,000
INCOME (LOSS) FROM OPERATIONS	7,638,000	(19,556,000)	(6,069,000)	(19,870,000)	19,754,000
NON-OPERATING INCOME (EXPENSE):
Interest income			46,000
Interest expense	(22,267,000)	(24,863,000)		(28,263,000)	(46,755,000)
Loss on extinguishment of debt					(6,686,000)
Other, net	(157,000)	605,000	(246,000)	606,000	(180,000)
Total non-operating income (expense)	(22,424,000)	(24,258,000)	(200,000)	(27,657,000)	(53,621,000)
INCOME (LOSS) BEFORE INCOME TAXES	(14,786,000)	(43,814,000)	(6,269,000)	(47,527,000)	(33,867,000)
PROVISION (BENEFIT) FOR INCOME TAXES	(3,894,000)	(16,850,000)	1,497,000	(18,161,000)	(10,979,000)
NET INCOME (LOSS) BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(10,892,000)	(26,964,000)	(7,766,000)	(29,366,000)	(22,888,000)
Net Income (Loss) of consolidated subsidiaries	493,000	(3,215,000)	1,392,000	(3,255,000)	1,854,000
NET INCOME (LOSS)	(10,399,000)	(30,179,000)	(6,374,000)	(32,621,000)	(21,034,000)
Guarantor [Member]
NET SALES	1,462,000	1,315,000	980,000	1,500,000	2,903,000
COST OF SALES (exclusive of amortization shown separately below)	1,034,000	1,370,000	722,000	1,596,000	1,951,000
GROSS MARGIN	428,000	(55,000)	258,000	(96,000)	952,000
OPERATING EXPENSES:
Research and development	1,462,000	3,012,000	2,471,000	3,343,000	3,105,000
Selling and marketing	477,000	543,000	568,000	609,000	938,000
Distribution	44,000	37,000	34,000	41,000	87,000
General and administrative	400,000	596,000	657,000	653,000	874,000
Amortization of intangibles	54,000	50,000	757,000	56,000	108,000
Total operating expenses	2,437,000	4,238,000	4,487,000	4,702,000	5,112,000
INCOME (LOSS) FROM OPERATIONS	(2,009,000)	(4,293,000)	(4,229,000)	(4,798,000)	(4,160,000)
NON-OPERATING INCOME (EXPENSE):
Other, net			14,000
Total non-operating income (expense)			14,000
INCOME (LOSS) BEFORE INCOME TAXES	(2,009,000)	(4,293,000)	(4,215,000)	(4,798,000)	(4,160,000)
PROVISION (BENEFIT) FOR INCOME TAXES	(853,000)	(1,555,000)	(1,598,000)	(1,732,000)	(1,565,000)
NET INCOME (LOSS) BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(1,156,000)	(2,738,000)	(2,617,000)	(3,066,000)	(2,595,000)
NET INCOME (LOSS)	(1,156,000)	(2,738,000)	(2,617,000)	(3,066,000)	(2,595,000)
Non-Guarantors [Member]
NET SALES	30,383,000	30,484,000	26,648,000	34,854,000	59,989,000
COST OF SALES (exclusive of amortization shown separately below)	17,339,000	21,196,000	12,944,000	24,177,000	33,893,000
GROSS MARGIN	13,044,000	9,288,000	13,704,000	10,677,000	26,096,000
OPERATING EXPENSES:
Research and development		35,000	34,000	39,000	34,000
Selling and marketing	5,720,000	4,411,000	4,621,000	4,880,000	10,522,000
Distribution	1,742,000	1,783,000	1,587,000	2,028,000	3,332,000
General and administrative	2,333,000	2,762,000	3,615,000	3,004,000	4,426,000
Amortization of intangibles	579,000	1,161,000	57,000	1,323,000	1,135,000
Total operating expenses	10,374,000	10,152,000	9,914,000	11,274,000	19,449,000
INCOME (LOSS) FROM OPERATIONS	2,670,000	(864,000)	3,790,000	(597,000)	6,647,000
NON-OPERATING INCOME (EXPENSE):
Interest income	28,000	43,000	117,000	54,000	39,000
Interest expense	(5,000)	(24,000)	(21,000)	(28,000)	(13,000)
Other, net	(85,000)	66,000	2,905,000	54,000	58,000
Total non-operating income (expense)	(62,000)	85,000	3,001,000	80,000	84,000
INCOME (LOSS) BEFORE INCOME TAXES	2,608,000	(779,000)	6,791,000	(517,000)	6,731,000
PROVISION (BENEFIT) FOR INCOME TAXES	959,000	(302,000)	2,782,000	(328,000)	2,282,000
NET INCOME (LOSS) BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	1,649,000	(477,000)	4,009,000	(189,000)	4,449,000
NET INCOME (LOSS)	1,649,000	(477,000)	4,009,000	(189,000)	4,449,000
Intersegment Elimination [Member]
NET SALES	(11,243,000)	(7,966,000)	(7,781,000)	(8,850,000)	(21,640,000)
COST OF SALES (exclusive of amortization shown separately below)	(11,243,000)	(7,966,000)	(7,781,000)	(8,850,000)	(21,640,000)
NON-OPERATING INCOME (EXPENSE):
Interest income	(21,000)	(37,000)	(21,000)	(48,000)	(29,000)
Interest expense	21,000	37,000	21,000	48,000	29,000
Net Income (Loss) of consolidated subsidiaries	(493,000)	3,215,000	(1,392,000)	3,255,000	(1,854,000)
NET INCOME (LOSS)	(493,000)	3,215,000	(1,392,000)	3,255,000	(1,854,000)
Total [Member]
NET SALES	82,056,000	83,035,000	74,910,000	94,425,000	167,210,000
COST OF SALES (exclusive of amortization shown separately below)	27,166,000	42,426,000	22,955,000	49,582,000	54,267,000
GROSS MARGIN	54,890,000	40,609,000	51,955,000	44,843,000	112,943,000
OPERATING EXPENSES:
Research and development	4,537,000	5,146,000	4,895,000	5,769,000	9,422,000
Selling and marketing	12,941,000	9,933,000	10,510,000	11,045,000	25,162,000
Distribution	4,721,000	4,575,000	3,952,000	5,225,000	9,229,000
General and administrative	10,813,000	11,205,000	38,175,000	11,959,000	20,929,000
Amortization of intangibles	12,404,000	12,463,000	931,000	14,110,000	24,785,000
Certain litigation expenses		22,000,000		22,000,000
Loss on disposition of fixed assets	1,175,000				1,175,000
Total operating expenses	46,591,000	65,322,000	58,463,000	70,108,000	90,702,000
INCOME (LOSS) FROM OPERATIONS	8,299,000	(24,713,000)	(6,508,000)	(25,265,000)	22,241,000
NON-OPERATING INCOME (EXPENSE):
Interest income	7,000	6,000	142,000	6,000	10,000
Interest expense	(22,251,000)	(24,850,000)		(28,243,000)	(46,739,000)
Loss on extinguishment of debt					(6,686,000)
Other, net	(242,000)	671,000	2,673,000	660,000	(122,000)
Total non-operating income (expense)	(22,486,000)	(24,173,000)	2,815,000	(27,577,000)	(53,537,000)
INCOME (LOSS) BEFORE INCOME TAXES	(14,187,000)	(48,886,000)	(3,693,000)	(52,842,000)	(31,296,000)
PROVISION (BENEFIT) FOR INCOME TAXES	(3,788,000)	(18,707,000)	2,681,000	(20,221,000)	(10,262,000)
NET INCOME (LOSS) BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(10,399,000)	(30,179,000)	(6,374,000)	(32,621,000)	(21,034,000)
NET INCOME (LOSS)	$ (10,399,000)	$ (30,179,000)	$ (6,374,000)	$ (32,621,000)	$ (21,034,000)