Summary of Significant Accounting Policies Aggregate Amortization Expense Related to Purchased Technology and Other Intangible Assets (Details) (Purchased Technology and Other Intangible Asset, USD $) In Thousands, unless otherwise specified	Jan. 31, 2014
Purchased Technology and Other Intangible Asset
Goodwill And Intangible Assets Disclosure
Expected amortization expense, year 1	$ 9,402
Expected amortization expense, year 2	6,516
Expected amortization expense, year 3	3,401
Expected amortization expense, year 4	2,361
Expected amortization expense, year 5	1,071
Finite-lived intangible assets, amortization expense, thereafter	48
Finite lived intangible assets future amortization	$ 22,799