Significant Accounting Policies - Computation of Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013	Jan. 25, 2015	Jan. 26, 2014	Jan. 27, 2013
Earnings Per Share, Basic and Diluted [Abstract]
Net income (loss)	$ (15,441)	$ 17,623	$ 17,898	$ 7,867	$ (210,808)	$ 12,453	$ 19,112	$ 14,777	$ 27,947	$ (164,466)	$ 41,939
Weighted average common shares outstanding - basic	66,763	67,162	67,208	67,300	67,523	67,792	67,614	66,956	67,108	67,471	65,809
Dilutive effect of employee equity incentive plans									577	0	1,663
Weighted average common shares outstanding - diluted	66,763	67,654	67,850	67,970	67,523	68,871	69,090	68,579	67,685	67,471	67,472
Basic earnings per common share (in dollars per share)	$ (0.23)	$ 0.26	$ 0.27	$ 0.12	$ (3.12)	$ 0.18	$ 0.28	$ 0.22	$ 0.42	$ (2.44)	$ 0.64
Diluted earnings per common share (in dollars per share)	$ (0.23)	$ 0.26	$ 0.26	$ 0.12	$ (3.12)	$ 0.18	$ 0.28	$ 0.22	$ 0.41	$ (2.44)	$ 0.62
Anti-dilutive shares not included in the above calculations									1,714	1,245	783