Geographic and Product Data (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 04, 2014	Mar. 29, 2013
Product Information [Line Items]
Net sales	$ 20,178	$ 18,001
Implantable Collamer Lenses [Member]
Product Information [Line Items]
Net sales	12,241	10,631
Intraocular Lenses [Member]
Product Information [Line Items]
Net sales	6,613	6,347
Core products [Member]
Product Information [Line Items]
Net sales	18,854	16,978
Other Surgical Products [Member]
Product Information [Line Items]
Net sales	$ 1,324	$ 1,023