SHORT-TERM INVESTMENTS (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016
Short-term investments:
Cost or Amortized Cost	$ 392,194	$ 470,736
Gross Unrealized Gains	318	131
Gross Unrealized Losses	(23)	(47)
Fair Value	392,489	470,820
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Due in 1 year or less	337,191
Due in 1-2 years	55,003
Total amortized cost	392,194
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Due in 1 year or less	337,301
Due in 1-2 years	55,188
Total fair value	392,489
Bank time deposits
Short-term investments:
Cost or Amortized Cost	186,478	265,570
Fair Value	186,478	265,570
Corporate bonds
Short-term investments:
Cost or Amortized Cost	205,716	205,166
Gross Unrealized Gains	318	131
Gross Unrealized Losses	(23)	(47)
Fair Value	$ 206,011	$ 205,250