Summary of Weighted Average Assumptions in Fair Value of Option Grant (Detail) (USD $)	3 Months Ended	9 Months Ended	3 Months Ended
Sep. 30, 2012 Employee Stock Option [Member]	Oct. 02, 2011 Employee Stock Option [Member]	Sep. 30, 2012 Employee Stock Option [Member]	Oct. 02, 2011 Employee Stock Option [Member]	Jul. 01, 2012 Employee Stock Purchase Plan [Member]	Jul. 03, 2011 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated grant date fair value per share	$ 2.50	$ 2.37	$ 2.84	$ 2.14	$ 2.19	$ 2.10
Expected life (years)	4 years 5 months 16 days	4 years 5 months 23 days	4 years 5 months 16 days	4 years 6 months 4 days	9 months 18 days	9 months 18 days
Risk-free interest rate	1.00%	1.00%	1.00%	2.00%	0.17%	0.02%
Volatility	52.00%	50.00%	47.00%	47.00%	41.00%	37.00%

The range of expected volatilities used and the weighted-average expected volatility for an entity using a valuation technique with different volatilities during the contractual term.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (f)(2)(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph e(2)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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