Geographic and Product Data (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2013	Jun. 29, 2012	Jun. 28, 2013	Jun. 29, 2012
Geographic and Product Data [Line Items]
Net sales	$ 18,164	$ 15,942	$ 36,165	$ 31,451
United States [Member]
Geographic and Product Data [Line Items]
Net sales	3,154	3,216	6,394	6,390
Japan [Member]
Geographic and Product Data [Line Items]
Net sales	4,648	4,094	9,387	7,951
Korea [Member]
Geographic and Product Data [Line Items]
Net sales	1,834	1,721	3,869	3,624
China [Member]
Geographic and Product Data [Line Items]
Net sales	2,230	2,141	4,301	4,247
Spain [Member]
Geographic and Product Data [Line Items]
Net sales	1,163	531	2,454	1,041
Others [Member]
Geographic and Product Data [Line Items]
Net sales	$ 5,135	$ 4,239	$ 9,760	$ 8,198