For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Revenue - Schedules of concentration of risk (Details) - Customer concentration - Epicel	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenue Concentration
Product Information [Line Items]
Concentration risk (as a percent)	6.00%	6.00%	10.00%	8.00%
Accounts Receivable Concentration
Product Information [Line Items]
Concentration risk (as a percent)			3.00%		2.00%