REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The approximate percentage of net revenue by type of customer was as follows:

	Year Ended December 31,
	2020		2019		2018
Healthcare insurers:
Fee-for-service	34	%	33	%	32	%
Capitated	3		3		3
Total healthcare insurers	37		36		35
Government payers	11		15		16
Client payers	38		32		32
Patients	11		13		13
Total DIS	97		96		96
DS	3		4		4
Net revenues	100	%	100	%	100	%

Accounts Receivable Disaggregation

The approximate percentage of net accounts receivable by type of customer as of December 31, 2020 and 2019 was as follows:

	2020	2019
Healthcare insurers	34%	22%
Government payers	6	11
Client payers	46	42
Patients (including coinsurance and deductible responsibilities)	11	20
Total DIS	97	95
DS	3	5
Net accounts receivable	100%	100%

Accounts Receivable, Allowance for Credit Loss

The following table summarizes the activity for the Company's allowance for credit losses during the year ended December 31, 2020, which principally relates to client payers:

	Allowance for Credit Losses
Balance, January 1, 2020	$	15
Provision for credit losses	19
Write-offs of accounts receivable, net of recoveries	(6)
Balance, December 31, 2020	$	28