Mergers and Acquisitions (Details) In Millions, unless otherwise specified		1 Months Ended			1 Months Ended
	Jul. 31, 2011 QuantaSol Limited ("QuantaSol") USD ($)	Jul. 31, 2011 QuantaSol Limited ("QuantaSol") Developed technology USD ($) Y	Jan. 31, 2012 Dyaptive Systems Inc USD ($)	Jan. 31, 2012 Dyaptive Systems Inc CAD	Jan. 31, 2012 Dyaptive Systems Inc Developed technology USD ($) Y	Jan. 31, 2012 Dyaptive Systems Inc Customer relationships USD ($) Y	Jan. 31, 2012 Dyaptive Systems Inc Other USD ($)
Acquisitions
Purchase consideration paid in cash	$ 3.7		$ 14.8	14.9
Working capital adjustment and holdback payment			2.0	2.0
Purchase price allocation to assets acquired
Total purchase price primarily allocated to developed technology		3.7
Net tangible assets acquired			3.4
Acquired finite-lived intangible assets					6.2	2.3	0.9
Goodwill			2.0
Total purchase price			14.8
Weighted-average estimated useful lives of acquired intangible assets
Estimated useful lives of acquired intangible assets (in years)		4			4	4
Fair value of acquired tangible assets
Cash			4.0
Accounts receivable			0.9
Inventories			0.8
Property and equipment			0.5
Accounts payable			(0.2)
Deferred revenue			(0.3)
Employee related liabilities			(2.3)
Net tangible assets acquired			$ 3.4