Business Segments - Schedule of Revenue Information by Product (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 01, 2022	Oct. 02, 2021	Oct. 01, 2022	Oct. 02, 2021
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		$ 14,635	$ 13,264	$ 41,777	$ 38,649
Cyclo G6
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		3,460	3,145	10,477	10,093
Retina
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		8,750	7,777	23,580	22,012
Other
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	[1]	$ 2,425	$ 2,342	$ 7,720	$ 6,544

[1] (1) Includes service contract revenues of $358 thousand and $387 thousand and $1,122 thousand and $1,061 thousand recognized during the three and nine months ended October 1, 2022 and October 2, 2021, respectively. Includes $351 thousand and $228 thousand and $985 thousand and $339 thousand recognized revenue related to the exclusive distribution rights during the three and nine months ended October 1, 2022 and October 2, 2021, respectively. Other also includes revenues from paid service, royalty, freight and legacy G probes.