Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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2. STOCK-BASED COMPENSATION (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012
Range Exercise Prices Options Outstanding Minimum	$ 0.59
Range Exercise Prices Options Outstanding Maximum	$ 9.94
Number of Options Outstanding, Ending	2,967	2,982	2,893	2,957
Weighted Average Remaining Contractual Life (Years) Options Outstanding	3 years 11 months
Weighted Average Exercise Price Outstanding, Ending	$ 1.80	$ 1.87	$ 2.00	$ 2.40
Number Exercisable Shares	1,750
Weighted Average Remaining Contractual Life (Years) Options Exercisable	2 years 10 months
Weighted Average Exercise Price Options Excercisable	$ 2.26
Aggregate Intrinsic Value Options Exercisable	$ 66
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	1,167
Weighted Average Remaining Contractual Life (Years) Options Outstanding	4 years 5 months
Weighted Average Exercise Price Outstanding, Ending	$ 0.76
Number Exercisable Shares	750
Weighted Average Remaining Contractual Life (Years) Options Exercisable	3 years 6 months
Weighted Average Exercise Price Options Excercisable	$ 0.81
Options Price Range B
Range Exercise Prices Options Outstanding Minimum	$ 1.10
Range Exercise Prices Options Outstanding Maximum	$ 2.52
Number of Options Outstanding, Ending	1,587
Weighted Average Remaining Contractual Life (Years) Options Outstanding	4 years 22 days
Weighted Average Exercise Price Outstanding, Ending	$ 1.56
Number Exercisable Shares	787
Weighted Average Remaining Contractual Life (Years) Options Exercisable	2 years 11 months
Weighted Average Exercise Price Options Excercisable	$ 1.76
Options Price Range C
Range Exercise Prices Options Outstanding Minimum	$ 6.00
Range Exercise Prices Options Outstanding Maximum	$ 9.30
Number of Options Outstanding, Ending	108
Weighted Average Remaining Contractual Life (Years) Options Outstanding	4 months 13 days
Weighted Average Exercise Price Outstanding, Ending	$ 8.53
Number Exercisable Shares	108
Weighted Average Remaining Contractual Life (Years) Options Exercisable	4 months 13 days
Weighted Average Exercise Price Options Excercisable	$ 8.53
Options Price Range D
Range Exercise Prices Options Outstanding Minimum	$ 9.94
Range Exercise Prices Options Outstanding Maximum	$ 9.94
Number of Options Outstanding, Ending	105
Weighted Average Remaining Contractual Life (Years) Options Outstanding	3 months 25 days
Weighted Average Exercise Price Outstanding, Ending	$ 9.94
Number Exercisable Shares	105
Weighted Average Remaining Contractual Life (Years) Options Exercisable	3 months 25 days
Weighted Average Exercise Price Options Excercisable	$ 9.94