Business Segments - Schedule of Revenue Information by Product (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 02, 2022	Apr. 03, 2021
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		$ 13,387	$ 11,959
Cyclo G6
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		3,540	3,349
Retina
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		7,301	6,660
Other
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	[1]	$ 2,546	$ 1,950

[1] Includes service contract revenues of $362 and $299 recognized during the three months ended April 2, 2022 and April 3, 2021, respectively. Includes $277 recognized revenue related to the exclusive distribution rights during the three ended April 2, 2022. Other also includes revenues from paid service, royalty, freight and legacy G probes.