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Equity-based compensation - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023	Jun. 28, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation	$ 2,064,000		$ 8,112,000
Unamortized compensation expense, options	3,506,000		3,506,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation expense, RSUs	$ 5,739,000		$ 5,739,000
Compensation expense net yet amortized, period for recognition			2 years 5 months 12 days
RSUs \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
RSUs \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense net yet amortized, period for recognition			2 years 11 months 1 day
Expiration period			10 years
Weighted-average fair value of stock options granted (in dollars per share)			$ 2.25
Stock options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
Stock options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available to be awarded (in shares)	1,393,982		1,393,982
Equity compensation		$ 99,000	$ 215,000	$ 292,000
Number of shares issued (in shares)		93,092	125,622	460,019
2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	$ 0	$ 0	$ 0	$ 0
2021 and 2023 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation		$ 1,734,000		$ 655,000
Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock closing price, (in dollars per share)					$ 11.64
Common Class A \| 2021 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized to be awarded (in shares)	19,564,333		19,564,333
Number of shares available to be awarded (in shares)	9,020,111		9,020,111
Common Class A \| 2023 Retention Equity Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized to be awarded (in shares)	600,000		600,000
Number of shares available to be awarded (in shares)	66,450		66,450