Geographic and Product Data (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 03, 2014	Sep. 27, 2013	Oct. 03, 2014	Sep. 27, 2013
Geographic and Product Data [Line Items]
Net sales	$ 18,188	$ 17,106	$ 58,414	$ 53,271
Japan [Member]
Geographic and Product Data [Line Items]
Net sales	4,792	4,040	14,349	13,427
United States [Member]
Geographic and Product Data [Line Items]
Net sales	2,875	2,993	8,676	9,388
China [Member]
Geographic and Product Data [Line Items]
Net sales	2,915	2,275	7,675	6,575
Korea [Member]
Geographic and Product Data [Line Items]
Net sales	1,098	1,982	5,671	5,851
Spain [Member]
Geographic and Product Data [Line Items]
Net sales	1,178	1,012	4,270	3,466
France [Member]
Geographic and Product Data [Line Items]
Net sales	820	595	2,956	1,722
Other [Member]
Geographic and Product Data [Line Items]
Net sales	$ 4,510	$ 4,209	$ 14,817	$ 12,842