Fair Value Measurements - Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis by Balance Sheet Line (Details) (Recurring, USD $) In Thousands, unless otherwise specified	Jan. 25, 2015	Jan. 26, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 23,271	$ 13,584
Long-term investments	0	3,674
Other assets	33	316
Total financial assets	23,304	17,574
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	23,271	13,584
Long-term investments	0	0
Other assets	0	0
Total financial assets	23,271	13,584
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Long-term investments	0	3,674
Other assets	33	316
Total financial assets	33	3,990
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Long-term investments	0	0
Other assets	0	0
Total financial assets	$ 0	$ 0