Segment and geographical information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended											12 Months Ended
	Dec. 30, 2011		Sep. 30, 2011	Jul. 01, 2011	Apr. 01, 2011	Dec. 31, 2010	Oct. 01, 2010	Jun. 25, 2010		Mar. 26, 2010		Dec. 30, 2011	Dec. 31, 2010	Dec. 25, 2009
Segment Reporting Information [Line Items]
Total Net sales	$ 90,473	[1]	$ 96,014	$ 94,758	$ 88,039	$ 101,184	$ 121,963	$ 116,473	[2]	$ 92,860	[3]	$ 369,284	$ 432,480	$ 398,803
Operating profit excluding severance, impairment and other associated costs												(1,257)	16,962
Severance, impairment and other associated costs												(14,719)	(32,799)	(82,867)
Costs related to unsolicited takeover attempt												(1,916)
Operating (loss) profit												(17,892)	(15,837)	(71,797)
Interest expense, net												(6,202)	(4,853)
Other income (expense), net												(561)	(4,356)	3,784
Net income (loss) from continuing operations before income taxes												(24,655)	(25,046)	(70,980)
Depreciation and amortization												9,892	17,410	18,454
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	90,473	[1]	96,014	94,758	88,039	101,184	121,963	116,473	[2]	92,860	[3]	369,284	432,480	398,803
Property, plant and equipment	28,605					30,681						28,605	30,681
China [Member]
Segment Reporting Information [Line Items]
Total Net sales												178,750	190,598	167,772
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												178,750	190,598	167,772
Property, plant and equipment	20,063					22,992						20,063	22,992
United States [Member]
Segment Reporting Information [Line Items]
Total Net sales												50,139	68,396	40,268
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												50,139	68,396	40,268
Property, plant and equipment	5,946					4,408						5,946	4,408
Asia, Other Than China [Member]
Segment Reporting Information [Line Items]
Total Net sales												48,353	68,264	77,464
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												48,353	68,264	77,464
Europe [Member]
Segment Reporting Information [Line Items]
Total Net sales												78,179	90,324	92,862
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												78,179	90,324	92,862
Property, plant and equipment	942					811						942	811
Other Geographical Groups of Countries [Member]
Segment Reporting Information [Line Items]
Total Net sales												13,863	14,898	20,437
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												13,863	14,898	20,437
Property, plant and equipment	71					91						71	91
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	1,583					0						1,583	0
North Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment	0					2,379						0	2,379
Network [Member]
Segment Reporting Information [Line Items]
Total Net sales												169,849	219,229	152,727
Loss from continuing operations before severance, impairment and other associated costs and income taxes												2,492	24,437
Depreciation and amortization												3,696	4,293
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												169,849	219,229	152,727
Power [Member]
Segment Reporting Information [Line Items]
Total Net sales												135,151	127,021	95,074
Loss from continuing operations before severance, impairment and other associated costs and income taxes												9,275	6,466
Depreciation and amortization												2,577	2,876
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												135,151	127,021	95,074
Wireless [Member]
Segment Reporting Information [Line Items]
Total Net sales												64,284	86,230	151,002
Loss from continuing operations before severance, impairment and other associated costs and income taxes												(13,024)	(13,941)
Depreciation and amortization												3,619	10,241
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales												$ 64,284	$ 86,230	$ 151,002

[1] During the fourth quarter of 2011, we recorded an income tax valuation allowance of $58.0 million, of which $38.0 million resulted in an increase in income tax expense. Refer to Note 7, Income taxes, for additional information.

[2] During the second quarter of 2010, we recorded a $3.6 million intangible asset impairment charge. Refer to Note 4, Goodwill and other intangible assets, for a description of the impairment.

[3] During the first quarter of 2010, we recorded impairments of $14.6 million to our goodwill and $11.5 million to our finite-lived intangible assets. Refer to Note 4, Goodwill and other intangible assets, for a description of the impairment.