Debt - Interest expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Oct. 01, 2022	Sep. 30, 2023	Oct. 01, 2022
Interest expense related to the notes
Interest Expense, Total	$ 1,359	$ 1,527	$ 4,611	$ 4,874
Convertible Senior Notes
Interest expense related to the notes
Contractual interest expense		826	1,493	2,511
Amortization of debt issuance costs		498	960	1,492
Interest Expense, Total		$ 1,324	$ 2,453	$ 4,003