Segment Information - Information About Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Product revenue	$ 83,464	$ 72,437	$ 237,834	$ 222,293
Service revenue	7,324	7,639	20,356	19,818
Operating income	23,379	21,803	61,533	62,894
Operating Segments [Member] | MVSD [Member]
Segment Reporting Information [Line Items]
Product revenue	75,184	64,971	215,515	198,935
Service revenue	2,758	3,291	7,151	6,989
Operating income	26,038	22,664	71,641	68,843
Operating Segments [Member] | SISD [Member]
Segment Reporting Information [Line Items]
Product revenue	8,280	7,466	22,319	23,358
Service revenue	4,566	4,348	13,205	12,829
Operating income	2,916	2,724	6,875	7,964
Reconciling Items [Member]
Segment Reporting Information [Line Items]
Operating income	$ (5,575)	$ (3,585)	$ (16,983)	$ (13,913)