2. STOCK-BASED COMPENSATION - Option Activity (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Aug. 31, 2014
Employee Service Share-based Compensation, Aggregate Disclosures [Abstract]
Available Shares, Beginning (in thousands)	1,145
Options granted (in thousands)	(625)
Options terminated (in thousands)	9
Available Shares, Ending (in thousands)	529
Options Outstanding, Beginning (in thousands)	3,002
Options Granted (in thousands)	625
Options terminated (in thousands)	(9)
Options exercised (in thousands)	(295)
Number of Options Outstanding, Ending (in thousands)	3,323
Weighted Average Exercise Price Outstanding, Beginning	$ 1.31
Weighted Average Exercise Price Granted	$ 2.65
Weighted Average Exercise Price Terminated	$ 1.27
Weighted Average Exercise Price Exercised	$ 1.07
Weighted Average Exercise Price Outstanding, Ending	$ 1.59
Aggregate Intrinsic Value, beginning balance	$ 2,913
Aggregate Intrinsic Value, ending balance	3,277
Options fully vested and expected to vest, ending (in thousands)	3,257
Options exercisable shares, ending (in thousands)	1,768
Weighted Average Exercise Price for Options fully vested and expected to vest, ending	$ 1.59
Weighted Average Exercise Price for Options exercisable, ending	$ 1.26
Aggregate Intrinsic Value for Options fully vested and expected to vest, ending	3,212
Options exercisable at August 31, 2014 Aggregate intrinsic value	$ 2,074