SHORT-TERM INVESTMENTS (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015
Short-term investments:
Cost or Amortized Cost	$ 379,598	$ 186,954
Gross Unrealized Gains		39
Gross Unrealized Losses	(158)	(64)
Fair Value	379,440	186,929
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Due in 1 year or less	372,880
Due in 1-2 years	6,718
Total amortized cost	379,598
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Due in 1 year or less	372,745
Due in 1-2 years	6,695
Total fair value	379,440
Bank time deposits
Short-term investments:
Cost or Amortized Cost	274,440	87,500
Fair Value	274,440	87,500
Corporate bonds
Short-term investments:
Cost or Amortized Cost	105,158	99,454
Gross Unrealized Gains		39
Gross Unrealized Losses	(158)	(64)
Fair Value	$ 105,000	$ 99,429