Geographic and Product Data (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 03, 2014	Sep. 27, 2013	Oct. 03, 2014	Sep. 27, 2013
Product Information [Line Items]
Net sales	$ 18,188	$ 17,106	$ 58,414	$ 53,271
Implantable Collamer Lenses [Member]
Product Information [Line Items]
Net sales	10,640	10,725	35,052	32,616
Intraocular Lenses [Member]
Product Information [Line Items]
Net sales	5,763	5,322	18,804	17,533
Core products [Member]
Product Information [Line Items]
Net sales	16,403	16,047	53,856	50,149
Other surgical products [Member]
Product Information [Line Items]
Net sales	$ 1,785	$ 1,059	$ 4,558	$ 3,122