Cash, cash equivalents and short-term investments (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 02, 2015	Jan. 03, 2014
Fair Value Measurements [Line Items]
Amortized Cost	$ 154,380	$ 156,103
Unrealized Gains	27	25
Unrealized Losses	(4)	(9)
Estimated Fair Value	154,403	156,119
Total short-term investments
Fair Value Measurements [Line Items]
Amortized Cost	24,890	33,155
Unrealized Gains	27	25
Unrealized Losses	(4)	(9)
Estimated Fair Value	24,913	33,171
Money market securities
Fair Value Measurements [Line Items]
Amortized Cost	45,478	37,099
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	45,478	37,099
Total cash and cash equivalents
Fair Value Measurements [Line Items]
Amortized Cost	129,490	122,948
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	129,490	122,948
Cash
Fair Value Measurements [Line Items]
Amortized Cost	84,012	85,849
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	84,012	85,849
Total cash equivalents
Fair Value Measurements [Line Items]
Amortized Cost	45,478	37,099
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	45,478	37,099
State and municipal bonds
Fair Value Measurements [Line Items]
Amortized Cost	24,890	33,155
Unrealized Gains	27	25
Unrealized Losses	(4)	(9)
Estimated Fair Value	$ 24,913	$ 33,171

Amount of accumulated gross unrealized gain on investments in available for sale securities.

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Amount of accumulated gross unrealized loss on investments in available for sale securities.

+ References

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- Definition

This item represents the fair value of cash, cash equivalents and short-term investments.

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

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