Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Product sales, net	$ 35,852	$ 33,627
Other revenue	222	941
Total revenue	36,074	34,568
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Product sales, net	419	477
MACI implants Aad kits
Disaggregation of Revenue [Line Items]
Product sales, net	25,995	23,797
Through Intermediary | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	15,190	13,206
Through Intermediary | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	3,369	4,280
Time-and-materials contract | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	861	849
Provider or Facility | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	5,634	4,466
Provider or Facility | NexoBid revenue
Disaggregation of Revenue [Line Items]
Other revenue	222	941
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net	522	519
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net	$ 9,857	$ 9,830