Note 17 - Consolidating Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2015	Nov. 30, 2014
Parent Company [Member]
NET SALES	$ 63,396	$ 61,381	$ 127,283	$ 127,649
COST OF SALES (exclusive of amortization shown separately below)	22,075	20,184	42,340	40,958
GROSS PROFIT	41,321	41,197	84,943	86,691
Research and development	3,310	2,756	5,949	5,396
Selling and marketing	6,675	6,598	13,075	12,835
Distribution	2,493	2,714	4,936	5,394
General and administrative	6,809	7,030	14,096	14,291
Amortization expense	11,972	11,971	23,945	23,942
Total operating expenses	31,259	31,069	62,001	61,858
INCOME (LOSS) FROM OPERATIONS	10,062	10,128	22,942	24,833
Interest income	39	15	78	18
Interest expense	(22,361)	(22,709)	(44,744)	(44,889)
Other, net	435	273	959	414
Total non-operating expense	(21,887)	(22,421)	(43,707)	(44,457)
(LOSS) INCOME BEFORE INCOME TAXES	(11,825)	(12,293)	(20,765)	(19,624)
(BENEFIT) PROVISION FOR INCOME TAXES	(1,636)	(4,215)	(3,886)	(6,404)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(10,189)	(8,078)	(16,879)	(13,220)
Net Income (Loss) of consolidated subsidiaries	(1,607)	(999)	(2,134)	(1,337)
NET (LOSS) INCOME	(11,796)	(9,077)	(19,013)	(14,557)
GROSS PROFIT	41,321	41,197	84,943	86,691
OPERATING EXPENSES:
Research and development	3,310	2,756	5,949	5,396
Selling and marketing	6,675	6,598	13,075	12,835
Distribution	2,493	2,714	4,936	5,394
General and administrative	6,809	7,030	14,096	14,291
Amortization expense	11,972	11,971	23,945	23,942
Total operating expenses	31,259	31,069	62,001	61,858
INCOME (LOSS) FROM OPERATIONS	10,062	10,128	22,942	24,833
NON-OPERATING (EXPENSE) INCOME:
Interest income	39	15	78	18
Interest expense	(22,361)	(22,709)	(44,744)	(44,889)
Other, net	435	273	959	414
Total non-operating expense	(21,887)	(22,421)	(43,707)	(44,457)
(LOSS) INCOME BEFORE INCOME TAXES	(11,825)	(12,293)	(20,765)	(19,624)
(BENEFIT) PROVISION FOR INCOME TAXES	(1,636)	(4,215)	(3,886)	(6,404)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	(10,189)	(8,078)	(16,879)	(13,220)
Net Income (Loss) of consolidated subsidiaries	(1,607)	(999)	(2,134)	(1,337)
NET (LOSS) INCOME	(11,796)	(9,077)	(19,013)	(14,557)
NET SALES	63,396	61,381	127,283	127,649
COST OF SALES (exclusive of amortization shown separately below)	22,075	20,184	42,340	40,958
GROSS PROFIT	41,321	41,197	84,943	86,691
Guarantor Subsidiaries [Member]
NET SALES	14,335	13,442	29,053	28,056
COST OF SALES (exclusive of amortization shown separately below)	9,111	8,366	18,079	17,993
GROSS PROFIT	5,224	5,076	10,974	10,063
Research and development	3,284	4,152	7,303	8,367
Selling and marketing	2,959	2,498	5,504	5,193
Distribution	334	400	723	788
General and administrative	1,528	1,223	2,828	2,269
Amortization expense	1,087	1,076	2,156	2,151
Total operating expenses	9,192	9,349	18,514	18,768
INCOME (LOSS) FROM OPERATIONS	$ (3,968)	$ (4,273)	$ (7,540)	$ (8,705)
Interest income
Interest expense	$ (114)	$ (123)	$ (233)	$ (247)
Other, net	(119)	(48)	(247)	(87)
Total non-operating expense	(233)	(171)	(480)	(334)
(LOSS) INCOME BEFORE INCOME TAXES	(4,201)	(4,444)	(8,020)	(9,039)
(BENEFIT) PROVISION FOR INCOME TAXES	(1,386)	(1,740)	(2,789)	(3,475)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ (2,815)	$ (2,704)	$ (5,231)	$ (5,564)
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ (2,815)	$ (2,704)	$ (5,231)	$ (5,564)
GROSS PROFIT	5,224	5,076	10,974	10,063
OPERATING EXPENSES:
Research and development	3,284	4,152	7,303	8,367
Selling and marketing	2,959	2,498	5,504	5,193
Distribution	334	400	723	788
General and administrative	1,528	1,223	2,828	2,269
Amortization expense	1,087	1,076	2,156	2,151
Total operating expenses	9,192	9,349	18,514	18,768
INCOME (LOSS) FROM OPERATIONS	$ (3,968)	$ (4,273)	$ (7,540)	$ (8,705)
NON-OPERATING (EXPENSE) INCOME:
Interest income
Interest expense	$ (114)	$ (123)	$ (233)	$ (247)
Other, net	(119)	(48)	(247)	(87)
Total non-operating expense	(233)	(171)	(480)	(334)
(LOSS) INCOME BEFORE INCOME TAXES	(4,201)	(4,444)	(8,020)	(9,039)
(BENEFIT) PROVISION FOR INCOME TAXES	(1,386)	(1,740)	(2,789)	(3,475)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ (2,815)	$ (2,704)	$ (5,231)	$ (5,564)
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ (2,815)	$ (2,704)	$ (5,231)	$ (5,564)
NET SALES	14,335	13,442	29,053	28,056
COST OF SALES (exclusive of amortization shown separately below)	9,111	8,366	18,079	17,993
GROSS PROFIT	5,224	5,076	10,974	10,063
Non-Guarantor Subsidiaries [Member]
NET SALES	35,132	40,049	70,431	79,621
COST OF SALES (exclusive of amortization shown separately below)	23,316	25,818	45,916	50,258
GROSS PROFIT	11,816	14,231	24,515	29,363
Research and development	166	207	338	431
Selling and marketing	5,185	6,277	10,227	12,401
Distribution	1,568	2,202	3,155	4,174
General and administrative	2,271	2,445	4,430	5,021
Amortization expense	532	604	1,068	1,239
Total operating expenses	9,722	11,735	19,218	23,266
INCOME (LOSS) FROM OPERATIONS	2,094	2,496	5,297	6,097
Interest income	34	45	59	123
Interest expense	(11)	(18)	(23)	(37)
Other, net	(238)	(11)	(762)	(38)
Total non-operating expense	(215)	16	(726)	48
(LOSS) INCOME BEFORE INCOME TAXES	1,879	2,512	4,571	6,145
(BENEFIT) PROVISION FOR INCOME TAXES	671	807	1,474	1,918
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ 1,208	$ 1,705	$ 3,097	$ 4,227
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ 1,208	$ 1,705	$ 3,097	$ 4,227
GROSS PROFIT	11,816	14,231	24,515	29,363
OPERATING EXPENSES:
Research and development	166	207	338	431
Selling and marketing	5,185	6,277	10,227	12,401
Distribution	1,568	2,202	3,155	4,174
General and administrative	2,271	2,445	4,430	5,021
Amortization expense	532	604	1,068	1,239
Total operating expenses	9,722	11,735	19,218	23,266
INCOME (LOSS) FROM OPERATIONS	2,094	2,496	5,297	6,097
NON-OPERATING (EXPENSE) INCOME:
Interest income	34	45	59	123
Interest expense	(11)	(18)	(23)	(37)
Other, net	(238)	(11)	(762)	(38)
Total non-operating expense	(215)	16	(726)	48
(LOSS) INCOME BEFORE INCOME TAXES	1,879	2,512	4,571	6,145
(BENEFIT) PROVISION FOR INCOME TAXES	671	807	1,474	1,918
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ 1,208	$ 1,705	$ 3,097	$ 4,227
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ 1,208	$ 1,705	$ 3,097	$ 4,227
NET SALES	35,132	40,049	70,431	79,621
COST OF SALES (exclusive of amortization shown separately below)	23,316	25,818	45,916	50,258
GROSS PROFIT	11,816	14,231	24,515	29,363
Consolidation, Eliminations [Member]
NET SALES	(16,614)	(18,595)	(33,806)	(36,609)
COST OF SALES (exclusive of amortization shown separately below)	$ (16,614)	$ (18,595)	$ (33,806)	$ (36,609)
GROSS PROFIT
Research and development
Selling and marketing
Distribution
General and administrative
Amortization expense
Total operating expenses
INCOME (LOSS) FROM OPERATIONS
Interest income	$ (32)	$ (28)	$ (54)	$ (53)
Interest expense	$ 32	$ 28	$ 54	$ 53
Other, net
Total non-operating expense
(LOSS) INCOME BEFORE INCOME TAXES
(BENEFIT) PROVISION FOR INCOME TAXES
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES
Net Income (Loss) of consolidated subsidiaries	$ 1,607	$ 999	$ 2,134	$ 1,337
NET (LOSS) INCOME	$ 1,607	$ 999	$ 2,134	$ 1,337
GROSS PROFIT
OPERATING EXPENSES:
Research and development
Selling and marketing
Distribution
General and administrative
Amortization expense
Total operating expenses
INCOME (LOSS) FROM OPERATIONS
NON-OPERATING (EXPENSE) INCOME:
Interest income	$ (32)	$ (28)	$ (54)	$ (53)
Interest expense	$ 32	$ 28	$ 54	$ 53
Other, net
Total non-operating expense
(LOSS) INCOME BEFORE INCOME TAXES
(BENEFIT) PROVISION FOR INCOME TAXES
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES
Net Income (Loss) of consolidated subsidiaries	$ 1,607	$ 999	$ 2,134	$ 1,337
NET (LOSS) INCOME	1,607	999	2,134	1,337
NET SALES	(16,614)	(18,595)	(33,806)	(36,609)
COST OF SALES (exclusive of amortization shown separately below)	$ (16,614)	$ (18,595)	$ (33,806)	$ (36,609)
GROSS PROFIT
NET SALES	$ 96,249	$ 96,277	$ 192,961	$ 198,717
COST OF SALES (exclusive of amortization shown separately below)	37,888	35,773	72,529	72,600
GROSS PROFIT	58,361	60,504	120,432	126,117
Research and development	6,760	7,115	13,590	14,194
Selling and marketing	14,819	15,373	28,806	30,429
Distribution	4,395	5,316	8,814	10,356
General and administrative	10,608	10,698	21,354	21,581
Amortization expense	13,591	13,651	27,169	27,332
Total operating expenses	50,173	52,153	99,733	103,892
INCOME (LOSS) FROM OPERATIONS	8,188	8,351	20,699	22,225
Interest income	41	32	83	88
Interest expense	(22,454)	(22,822)	(44,946)	(45,120)
Other, net	78	214	(50)	289
Total non-operating expense	(22,335)	(22,576)	(44,913)	(44,743)
(LOSS) INCOME BEFORE INCOME TAXES	(14,147)	(14,225)	(24,214)	(22,518)
(BENEFIT) PROVISION FOR INCOME TAXES	(2,351)	(5,148)	(5,201)	(7,961)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ (11,796)	$ (9,077)	$ (19,013)	$ (14,557)
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ (11,796)	$ (9,077)	$ (19,013)	$ (14,557)
GROSS PROFIT	58,361	60,504	120,432	126,117
Research and development	6,760	7,115	13,590	14,194
Selling and marketing	14,819	15,373	28,806	30,429
Distribution	4,395	5,316	8,814	10,356
General and administrative	10,608	10,698	21,354	21,581
Amortization expense	13,591	13,651	27,169	27,332
Total operating expenses	50,173	52,153	99,733	103,892
INCOME (LOSS) FROM OPERATIONS	8,188	8,351	20,699	22,225
Interest income	41	32	83	88
Interest expense	(22,454)	(22,822)	(44,946)	(45,120)
Other, net	78	214	(50)	289
Total non-operating expense	(22,335)	(22,576)	(44,913)	(44,743)
(LOSS) INCOME BEFORE INCOME TAXES	(14,147)	(14,225)	(24,214)	(22,518)
(BENEFIT) PROVISION FOR INCOME TAXES	(2,351)	(5,148)	(5,201)	(7,961)
NET (LOSS) INCOME BEFORE EARNINGS OF CONSOLIDATED SUBSIDIARIES	$ (11,796)	$ (9,077)	$ (19,013)	$ (14,557)
Net Income (Loss) of consolidated subsidiaries
NET (LOSS) INCOME	$ (11,796)	$ (9,077)	$ (19,013)	$ (14,557)
NET SALES	96,249	96,277	192,961	198,717
COST OF SALES (exclusive of amortization shown separately below)	37,888	35,773	72,529	72,600
GROSS PROFIT	$ 58,361	$ 60,504	$ 120,432	$ 126,117