Disaggregation of Sales, Geographic Sales and Product Sales - Net Sales by Products and Services (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2021	Apr. 03, 2020
Product Information [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 4,251	$ 5,847
Total net sales	50,752	35,187
ICLs [Member]
Product Information [Line Items]
Revenue from contract with customer, excluding assessed tax	46,501	29,340
IOLs [Member]
Product Information [Line Items]
Revenue from contract with customer, excluding assessed tax	3,725	3,994
Other surgical products [Member]
Product Information [Line Items]
Revenue from contract with customer, excluding assessed tax	$ 526	$ 1,853