Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Product sales, net	$ 38,326	$ 33,718	$ 111,004	$ 106,025
Other revenue	225	788	667	2,568
Total revenue	38,551	34,506	111,671	108,593
Accounting Standards Update 2014-09 | Change in estimates related to prior periods
Disaggregation of Revenue [Line Items]
Product sales, net	(428)	153	1,142	(125)
MACI implants Aad kits
Disaggregation of Revenue [Line Items]
Product sales, net	31,009	23,881	85,617	74,203
Through Intermediary | MACI implants and kits | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	19,377	15,149	50,718	46,547
Through Intermediary | MACI implants and kits | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	4,207	3,463	12,015	11,357
Time-and-materials contract | MACI implants and kits | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	898	644	2,331	1,901
Provider or Facility | MACI implants and kits | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	6,457	3,895	17,846	12,876
Provider or Facility | NexoBid revenue
Disaggregation of Revenue [Line Items]
Other revenue	225	788	667	2,568
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net	498	577	1,565	1,647
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net	$ 7,317	$ 9,837	$ 25,387	$ 31,822