INCOME TAXES (Details 4) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income taxes
Decrease in the valuation allowance due to the utilization of NOLs	$ 20,400,000
Net deferred tax liability related to acquired intellectual property	31,800,000
Additional tax benefits from stock option exercises that have not been recognized	8,437,000	22,089,000
ASC 718
Income taxes
Additional tax benefits from stock option exercises that have not been recognized	34,500,000
Total tax benefit from the exercise of stock options including unrecognized benefits	$ 42,900,000