Segment information - Schedule of Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023
Segment Reporting Information [Line Items]
Revenue	$ 12,532	$ 0
Gross profit	6,294	0
Operating loss	(7,562)	(19,846)
Depreciation and amortization	3,402	1,452
Interest (expense) income, net	(879)	2,250
Net loss after provision for income taxes	(9,286)	(17,524)
Continuing and Discontinued Operation
Segment Reporting Information [Line Items]
Revenue	12,532	3,795
Gross profit	6,294	(197)
Operating loss	(7,562)	(9,408)
Depreciation and amortization	3,402	1,548
Interest (expense) income, net	(879)	2,069
Net loss after provision for income taxes	(6,245)	(7,812)
Fintech
Segment Reporting Information [Line Items]
Revenue	12,532	0
Gross profit	6,294	0
Operating loss	905	0
Depreciation and amortization	1,316	0
Interest (expense) income, net	(499)	0
Net loss after provision for income taxes	469	0
Biotech
Segment Reporting Information [Line Items]
Revenue	0	0
Gross profit	0	0
Operating loss	(2,148)	(1,531)
Depreciation and amortization	2,086	1,452
Interest (expense) income, net	0	0
Net loss after provision for income taxes	(2,086)	(1,532)
Corporate and other
Segment Reporting Information [Line Items]
Revenue	0	0
Gross profit	0	0
Operating loss	(6,319)	(18,315)
Depreciation and amortization	0	0
Interest (expense) income, net	(380)	2,250
Net loss after provision for income taxes	(4,628)	(15,563)
Discontinue operations | Discontinued operations
Segment Reporting Information [Line Items]
Revenue	0	3,795
Gross profit	0	(197)
Operating loss	0	10,438
Depreciation and amortization	0	96
Interest (expense) income, net	0	(181)
Net loss after provision for income taxes	$ 0	$ 9,283