FAIR VALUE MEASUREMENTS (Details) - Recurring basis - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015
Total | Cash and Cash Equivalents
Assets measured at fair value on a recurring basis
Money market funds	$ 598,781	$ 544,334
Bank-time deposits	17,722	79,852
Total | Short term investments.
Assets measured at fair value on a recurring basis
Bank-time deposits	275,140	87,500
Corporate bonds	99,873	99,429
Total | Prepaid expenses and other
Assets measured at fair value on a recurring basis
Foreign currency forward contracts		587
Total | Accrued Expenses and other current liabilities
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	(5)
Quoted prices in active markets for identical assets (level 1) | Cash and Cash Equivalents
Assets measured at fair value on a recurring basis
Money market funds	598,781	544,334
Bank-time deposits	17,722	79,852
Quoted prices in active markets for identical assets (level 1) | Short term investments.
Assets measured at fair value on a recurring basis
Bank-time deposits	275,140	87,500
Significant other observable inputs (level 2) | Short term investments.
Assets measured at fair value on a recurring basis
Corporate bonds	99,873	99,429
Significant other observable inputs (level 2) | Prepaid expenses and other
Assets measured at fair value on a recurring basis
Foreign currency forward contracts		$ 587
Significant other observable inputs (level 2) | Accrued Expenses and other current liabilities
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	$ (5)