Related-Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2013 Installment	Jan. 31, 2012 Installment	Jan. 31, 2011
Related Party Transaction [Line Items]
Percentage of entity's voting stock owned by related party	10.00%
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Number of quarterly payments	12	17
Total commitment payment of license	$ 5.1
Payment for license agreements	1.8	1.9	0.9
Operating lease expense related to license agreements included in research and development cost	1.8	1.6	0.6
Shareholder [Member]
Related Party Transaction [Line Items]
Percentage of investor own voting stock	4.60%	7.40%
Recognized revenue from related party	76.5	77.6	85.7
Account receivables from related party	$ 8.2	$ 7.8

The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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