Income taxes - Schedule of components of deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Fixed assets and intangibles	$ 5	$ 17
Leases	255	378
Accrued expenses	4,887	2,741
Net operating loss carryforward	52,179	31,868
Stock options	3,528	5,508
R&D credit carryforward	3,431	616
Other	1,998	402
Subtotal	66,283	41,530
Less: valuation allowance	(65,659)	(40,760)
Total deferred tax assets	624	770
Deferred tax liabilities:
Leases	(243)	(370)
Prepaid expenses	(381)	(400)
Total deferred tax liability	(624)	(770)
Net deferred tax asset (liability)	$ 0	$ 0