CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Operating activities:
Net loss	$ (82.4)	$ (129.6)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation, amortization and accretion	24.1	28.4
Stock-based compensation expense	54.4	66.8
Deferred income taxes	13.3	(0.4)
Restructuring and other facility exit costs, net	22.5	(0.3)
Other operating activities	10.5	7.3
Changes in operating assets and liabilities
Accounts receivable	231.4	220.9
Prepaid expenses and other current assets	(1.4)	6.2
Accounts payable and accrued liabilities	(227.7)	(133.1)
Deferred revenue	(58.5)	13.3
Accrued income taxes	(3.1)	(34.3)
Net cash (used in) provided by operating activities	(16.9)	45.2
Investing activities:
Purchases of marketable securities	(9.9)	(119.4)
Sales of marketable securities	6.2	100.0
Maturities of marketable securities	68.6	282.6
Capital expenditures	(16.7)	(8.6)
Other investing activities	(0.6)	3.9
Net cash provided by investing activities	47.6	258.5
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	49.1	50.1
Taxes paid related to net share settlement of equity awards	(38.8)	(33.0)
Repurchases of common stock	(22.0)	(195.9)
Net cash used in financing activities	(11.7)	(178.8)
Effect of exchange rate changes on cash and cash equivalents	(4.0)	2.2
Net increase in cash and cash equivalents	15.0	127.1
Cash and cash equivalents at beginning of period	1,078.0	1,213.1
Cash and cash equivalents at end of period	$ 1,093.0	$ 1,340.2