Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Operating activities
Consolidated net income (loss)	$ (11,572)	$ 69,697	$ 84,692
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	157,286	75,746	53,177
Amortization of debt discount and transaction costs	10,347	19,621	728
Amortization of deferred commissions	107,195	80,159	63,891
Expenses related to stock-based awards	229,258	120,429	88,892
Excess tax benefits from employee stock plans	(6,018)	(35,991)	(51,539)
Changes in assets and liabilities:
Accounts receivable, net	(244,947)	(102,507)	(54,522)
Deferred commissions	(167,199)	(121,247)	(82,336)
Prepaid expenses and other current assets	(10,736)	2,001	(3,899)
Other assets	2,883	(9,770)	(1,405)
Accounts payable	12,644	1,246	(1,588)
Accrued expenses and other current liabilities	67,692	132,004	64,498
Deferred revenue	444,674	227,693	110,322
Net cash provided by operating activities	591,507	459,081	270,911
Investing activities
Business combinations, net of cash acquired	(422,699)	(403,331)	(11,999)
Land activity and building improvements	(19,655)	(277,944)	0
Strategic investments	(37,370)	(20,105)	(4,400)
Purchases of marketable securities	(623,231)	(1,682,549)	(1,317,952)
Sales of marketable securities	724,564	1,197,492	874,573
Maturities of marketable securities	40,346	214,770	130,663
Capital expenditures	(151,645)	(90,887)	(49,501)
Net cash used in investing activities	(489,690)	(1,062,554)	(378,616)
Financing activities
Proceeds from borrowings on convertible debt	0	0	567,094
Proceeds from issuance of warrants	0	0	59,283
Purchase of convertible note hedge	0	0	(126,500)
Purchase of subsidiary stock	0	(171,964)	0
Proceeds from equity plans	116,565	160,402	93,856
Excess tax benefits from employee stock plans	6,018	35,991	51,539
Contingent consideration payment related to prior business combinations	(16,200)	0	0
Principal payments on capital lease obligations	(30,533)	(10,355)	(8,119)
Net cash provided by financing activities	75,850	14,074	637,153
Effect of exchange rate changes	5,325	2,385	(1,976)
Net increase (decrease) in cash and cash equivalents	182,992	(587,014)	527,472
Cash and cash equivalents, beginning of period	424,292	1,011,306	483,834
Cash and cash equivalents, end of period	607,284	424,292	1,011,306
Cash paid during the period for:
Interest	6,587	5,290	1,069
Income taxes, net of tax refunds	20,981	90	28,479
Non-cash financing and investing activities:
Fixed assets acquired under capital leases	57,839	13,224	17,000
Fair value of stock options assumed	$ 7,318	$ 0	$ 0