CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS - SUMMARY (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Oct. 31, 2014	Jan. 31, 2014
Commercial paper and corporate debt securities (available-for-sale)
Schedule of Available-for-sale Securities
Cost basis	$ 13,774	$ 9,402
Gross Unrealized Gains	22	4
Gross Unrealized Losses	0	0
Estimated Fair Value	13,796	9,406
Bank time deposits
Schedule of Available-for-sale Securities
Cost basis	26,340	22,643
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	26,340	22,643
Total short-term investments
Schedule of Available-for-sale Securities
Cost basis	40,114	32,045
Gross Unrealized Gains	22	4
Gross Unrealized Losses	0	0
Estimated Fair Value	40,136	32,049
Cash and bank time deposits
Schedule of Available-for-sale Securities
Cost basis	189,142	314,604
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	189,142	314,604
Money market funds
Schedule of Available-for-sale Securities
Cost basis	194	14,023
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	194	14,023
Commercial paper
Schedule of Available-for-sale Securities
Cost basis	2,999	49,986
Gross Unrealized Gains	0	5
Gross Unrealized Losses	0	0
Estimated Fair Value	2,999	49,991
Total cash and cash equivalents
Schedule of Available-for-sale Securities
Cost basis	192,335	378,613
Gross Unrealized Gains	0	5
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 192,335	$ 378,618