Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Product sales, net	$ 39,390	$ 30,499	$ 26,151	$ 21,810	$ 31,335	$ 22,484	$ 19,011	$ 18,027	$ 117,850	$ 90,857	$ 62,760
Revenues									117,850	90,857	63,924
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Product sales, net									654	(182)	(350)
Other revenue
Disaggregation of Revenue [Line Items]
Product sales, net									0	0	1,164
Through Intermediary | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net									56,185	42,926	37,796
Through Intermediary | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net									17,076	8,621	1,299
Time-and-materials contract | Implants | Time-and-materials contract
Disaggregation of Revenue [Line Items]
Product sales, net									1,529	2,257	0
Provider or Facility | Implants | Contract rate
Disaggregation of Revenue [Line Items]
Product sales, net									13,933	12,122	3,393
Directly to consumer | Biopsy kits
Disaggregation of Revenue [Line Items]
Product sales, net									2,243	1,997	1,764
Directly to consumer | Epicel
Disaggregation of Revenue [Line Items]
Product sales, net									$ 26,230	$ 23,116	$ 18,858