Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Jan. 26, 2014	Jan. 27, 2013
Components of Deferred Tax Assets and Liabilities [Abstract]
Total current deferred tax liability	$ (930)	$ (4,221)
Net deferred tax (liability) asset	(1,262)	34,773
Current Deferred Tax Asset [Member]
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred revenue	2,773	1,889
Inventory reserve	3,032	567
Payroll and related accruals	2,133	2,444
Bad debt reserve	416	323
Accrued service fees	591	626
Other deferred assets	1,562	2,593
Valuation allowance	(7,321)	(969)
Total current deferred tax asset	3,186	7,473
Noncurrent Deferred Tax Asset [Member]
Components of Deferred Tax Assets and Liabilities [Abstract]
Payroll and related accruals	6,268	5,389
Other deferred assets	3,567	3,395
Research and development charges	2,109	2,900
Research credit carryforward	39,350	49,257
Acquired NOL carryforward	31,165	28,595
Stock-based compensation	5,732	8,456
Valuation allowance	(53,931)	(7,351)
Total non-current deferred tax asset	34,260	90,641
Current Deferred Tax Liability [Member]
Components of Deferred Tax Assets and Liabilities [Abstract]
Inventory reserve - foreign	(430)	(1,618)
Bad debt reserve - foreign	(223)	(773)
Depreciation - foreign	0	(1,744)
Other deferred tax liability	(517)	(86)
Total current deferred tax liability	(1,170)	(4,221)
Noncurrent Deferred Tax Liability [Member]
Components of Deferred Tax Assets and Liabilities [Abstract]
Other deferred tax liability	(1,377)	(1,435)
Purchase accounting deferred tax liability	(32,466)	(49,181)
Depreciation and amortization	(3,695)	(8,504)
Total non-current deferred tax liability	$ (37,538)	$ (59,120)