Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Product sales, net	$ 36,826	$ 38,680	$ 72,678	$ 72,307
Other revenue	220	839	442	1,780
Total revenue	37,046	39,519	73,120	74,087
Accounting Standards Update 2014-09 | Change in estimates related to prior periods
Disaggregation of Revenue [Line Items]
Product sales, net	1,733	(392)	1,898	(74)
MACI implants Aad kits
Disaggregation of Revenue [Line Items]
Product sales, net	28,613	26,525	54,607	50,322
Through Intermediary | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	15,714	17,972	31,009	31,200
Through Intermediary | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	4,295	3,502	7,803	7,917
Time-and-materials contract | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net	570	405	1,441	1,255
Time-and-materials contract | Implants | Time-and-materials contract | Change in estimates related to prior periods
Disaggregation of Revenue [Line Items]
Product sales, net	1,400
Provider or Facility | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net	5,756	4,487	11,390	8,954
Provider or Facility | NexoBid revenue
Disaggregation of Revenue [Line Items]
Other revenue	220	839	442	1,780
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net	545	551	1,066	1,070
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net	$ 8,213	$ 12,155	$ 18,071	$ 21,985