2. STOCK-BASED COMPENSATION (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	May 31, 2013	Aug. 31, 2012
Range Exercise Prices Options Outstanding Minimum	$ 0.59
Range Exercise Prices Options Outstanding Maximum	$ 2.52
Number of Options Outstanding, Ending (in thousands)	3,323	2,956
Weighted Average Remaining Contractual Life (Years) Options Outstanding	4 years 4 months 6 days
Weighted Average Exercise Price Outstanding, Ending	$ 1.27	$ 1.79
Number Exercisable Shares (in thousands)	1,816		1,541
Weighted Average Remaining Contractual Life (Years) Options Exercisable	3 years 1 month 20 days
Weighted Average Exercise Price Options Excercisable	$ 1.28		$ 2.70
Aggregate Intrinsic Value Options Exercisable	$ 769
Options Price Range A
Range Exercise Prices Options Outstanding Minimum	$ 0.59
Range Exercise Prices Options Outstanding Maximum	$ 0.97
Number of Options Outstanding, Ending (in thousands)	1,101
Weighted Average Remaining Contractual Life (Years) Options Outstanding	3 years 11 months 8 days
Weighted Average Exercise Price Outstanding, Ending	$ 0.76
Number Exercisable Shares (in thousands)	846
Weighted Average Remaining Contractual Life (Years) Options Exercisable	3 years 6 months 4 days
Weighted Average Exercise Price Options Excercisable	$ 0.80
Options Price Range B
Range Exercise Prices Options Outstanding Minimum	$ 1.09
Range Exercise Prices Options Outstanding Maximum	$ 1.42
Number of Options Outstanding, Ending (in thousands)	1,484
Weighted Average Remaining Contractual Life (Years) Options Outstanding	5 years 7 months 2 days
Weighted Average Exercise Price Outstanding, Ending	$ 1.28
Number Exercisable Shares (in thousands)	453
Weighted Average Remaining Contractual Life (Years) Options Exercisable	4 years 6 months 11 days
Weighted Average Exercise Price Options Excercisable	$ 1.28
Options Price Range C
Range Exercise Prices Options Outstanding Minimum	$ 1.55
Range Exercise Prices Options Outstanding Maximum	$ 1.95
Number of Options Outstanding, Ending (in thousands)	487
Weighted Average Remaining Contractual Life (Years) Options Outstanding	3 years 5 months 12 days
Weighted Average Exercise Price Outstanding, Ending	$ 1.88
Number Exercisable Shares (in thousands)	277
Weighted Average Remaining Contractual Life (Years) Options Exercisable	2 years 14 days
Weighted Average Exercise Price Options Excercisable	$ 1.93
Options Price Range D
Range Exercise Prices Options Outstanding Minimum	$ 2.15
Range Exercise Prices Options Outstanding Maximum	$ 2.52
Number of Options Outstanding, Ending (in thousands)	251
Weighted Average Remaining Contractual Life (Years) Options Outstanding	6 months 18 days
Weighted Average Exercise Price Outstanding, Ending	$ 2.24
Number Exercisable Shares (in thousands)	240
Weighted Average Remaining Contractual Life (Years) Options Exercisable	5 months 26 days
Weighted Average Exercise Price Options Excercisable	$ 2.25