Geographic Information and Concentration of Risk - Net Sales Activity by Product Line (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013	Jan. 27, 2013	Oct. 28, 2012	Jul. 29, 2012	Apr. 29, 2012	Jan. 26, 2014	Jan. 27, 2013	Jan. 29, 2012
Product Information [Line Items]
Net sales	$ 126,534	$ 141,026	$ 165,010	$ 162,407	$ 150,603	$ 160,878	$ 150,704	$ 116,642	$ 594,977	$ 578,827	$ 480,601
Signal Integrity and Timing
Product Information [Line Items]
Net sales									288,374	263,090	139,695
Concentration risk, percentage									49.00%	45.00%	29.00%
Protection
Product Information [Line Items]
Net sales									198,514	198,866	209,726
Concentration risk, percentage									33.00%	34.00%	44.00%
Power Management and High Reliability
Product Information [Line Items]
Net sales									58,295	66,427	74,056
Concentration risk, percentage									10.00%	12.00%	15.00%
Wireless and Sensing
Product Information [Line Items]
Net sales									$ 49,794	$ 50,444	$ 57,124
Concentration risk, percentage									8.00%	9.00%	12.00%