Significant Accounting Policies - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 25, 2015	Jul. 26, 2015	Apr. 26, 2015	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Earnings Per Share, Basic and Diluted [Abstract]
Net income (loss)	$ 1,247	$ 10,704	$ (313)	$ (142)	$ (15,441)	$ 17,623	$ 17,898	$ 7,867	$ 11,497	$ 27,947	$ (164,466)
Weighted average common shares outstanding - basic	64,934	65,117	65,920	66,713	66,763	67,162	67,208	67,300	65,657	67,108	67,471
Dilutive effect of employee equity incentive plans									304	577	0
Weighted average common shares outstanding - diluted	65,225	65,217	65,920	66,713	66,763	67,654	67,850	67,970	65,961	67,685	67,471
Basic earnings per common share (in dollars per share)	$ 0.02	$ 0.16	$ 0.00	$ 0.00	$ (0.23)	$ 0.26	$ 0.27	$ 0.12	$ 0.18	$ 0.42	$ (2.44)
Diluted earnings per common share (in dollars per share)	$ 0.02	$ 0.16	$ 0.00	$ 0.00	$ (0.23)	$ 0.26	$ 0.26	$ 0.12	$ 0.17	$ 0.41	$ (2.44)
Anti-dilutive shares not included in the above calculations									2,569	1,714	1,245