Revenue (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Schedule of revenue by product and customer

The following table and description below shows the products from which the Company generated its revenue:

	Three Months Ended September 30,				Nine Months Ended September 30,
Revenue by product (in thousands)	2018		2017		2018			2017
MACI and Carticel implants and kits
Implants - based on contracted rate	$	243	$	8,046	$	18,354		$	11,145
Implants - subject to third party reimbursement	15,593		1,079		23,156			15,172
Biopsy kits - direct bill	488		412		1,392			1,274
Change in estimates related to prior periods	125		372		(273		)	230
Epicel
Direct bill (hospital)	6,035		4,351		16,893			12,753
Total revenue	$	22,484	$	14,260	$	59,522		$	40,574

Schedules of concentration of risk

The Company's total revenue and accounts receivable balances were comprised of the following concentrations from its largest customers of Carticel, MACI and Epicel, as follows:

	Revenue Concentration							Accounts Receivable Concentration
	Three Months Ended September 30,			Nine Months Ended September 30,				September 30,	December 31,
	2018	2017		2018		2017		2018	2017
MACI and Carticel1	<10%	55	%	24	%	25	%	<10%	46	%
Epicel	<10%	10	%	<10%		13	%	<10%	<10%

¹ Carticel was removed from the market at the end of the second quarter of 2017.