Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 03, 2011	Jul. 04, 2010	Jul. 03, 2011	Jul. 04, 2010
Information about the Company's segments
Product revenue	$ 77,566	$ 67,067	$ 146,443	$ 121,680
Service	5,827	4,744	11,344	9,098
Operating income	24,042	19,241	41,410	30,493
Segment Information (Textuals) [Abstract]
Number of reportable segments	2		2
MVSD [Member]
Information about the Company's segments
Product revenue	70,942	59,345	133,759	109,005
Service	1,834	1,653	3,803	3,150
Operating income	26,587	22,939	48,614	38,384
SISD [Member]
Information about the Company's segments
Product revenue	6,624	7,722	12,684	12,675
Service	3,993	3,091	7,541	5,948
Operating income	2,022	1,330	3,019	1,002
Reconciling Items [Member]
Information about the Company's segments
Operating income	$ (4,567)	$ (5,028)	$ (10,223)	$ (8,893)