Revenue (Tables)

3 Months Ended

Mar. 31, 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 March 31,
Revenue by product (in thousands)	2018			2017
MACI and Carticel implants and kits
Implants - based on contracted rate	$	10,749		$	297
Implants - subject to third party reimbursement	1,008			6,385
Biopsy kits - direct bill	436			439
Change in estimates related to prior periods	(138		)	(2,114		)
Epicel
Direct bill (hospital)	5,972			4,354
Total revenue	$	18,027		$	9,361

Schedules of concentration of risk

The Company's total revenue and accounts receivable balances were comprised of the following concentrations greater than 10% from its largest customers of Carticel, MACI and Epicel, as follows:

	Revenue Concentration				Accounts Receivable Concentration
	Three months ended March 31,				March 31,		December 31,
	2018		2017		2018		2017
MACI and Carticel1	43	%	—	%	41	%	46	%
Epicel	14	%	16	%	—	%	—	%

¹ Removed from market at the end of the second quarter of 2017