Business Segments and Geographical Information - Schedule of Revenue Information by Product (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Jan. 01, 2022
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		$ 56,972	$ 53,903
Cyclo G6
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		14,694	13,950
Retina
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues		31,657	31,106
Other
Entity Wide Information Revenue From External Customer [Line Items]
Total revenues	[1]	$ 10,621	$ 8,847

[1] (1) Includes service contract revenues of $1,509 thousand and $1,386 thousand recognized during fiscal years 2022 and 2021, respectively. Includes $1,348 thousand and $615 thousand recognized revenue related to the exclusive distribution rights during fiscal years 2022 and 2021. Other also includes revenues from paid service, royalty, freight and legacy G probes.