Geographic and Product Data (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2015	Jul. 04, 2014	Jul. 03, 2015	Jul. 04, 2014
Product Information [Line Items]
Net sales	$ 18,657	$ 20,048	$ 37,514	$ 40,226
Implantable Collamer Lenses [Member]
Product Information [Line Items]
Net sales	12,236	12,172	24,490	24,413
Intraocular Lenses [Member]
Product Information [Line Items]
Net sales	5,204	6,428	10,562	13,041
Core products [Member]
Product Information [Line Items]
Net sales	17,440	18,600	35,052	37,454
Other surgical products [Member]
Product Information [Line Items]
Net sales	$ 1,217	$ 1,448	$ 2,462	$ 2,772