Business Segments - Schedule of Revenue Information by Product (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 01, 2023	Apr. 02, 2022
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		$ 13,706	$ 13,387
Cyclo G6
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		3,669	3,540
Retina
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		7,214	7,301
Other
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	[1]	$ 2,823	$ 2,546

[1] (1) Includes service contract revenues of $383 thousand and $362 thousand recognized during the three months ended April 1, 2023 and April 2, 2022, respectively. Includes $364 thousand and $277 thousand recognized revenue related to the exclusive distribution rights during the three months ended April 1, 2023 and April 2, 2022, respectively. Other also includes revenues from paid service, royalty, freight and legacy G probes.