REVENUE

On January 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers, using the modified retrospective approach applied to those contracts that were not completed as of that date. The Company did not record a cumulative catch-up adjustment, as the timing and measurement of revenue for the Company’s customers is similar to its prior revenue recognition model.

ASC 606 requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration that it expects to be entitled to in exchange for those goods or services. ASC 606 requires application of a five-step model to determine when to recognize revenue and at what amount. The revenue standard applies to all contracts with customers and revenues are to be recognized when control of the promised goods or services is transferred to the Company’s patients in an amount that reflects consideration expected to be received in exchange for those goods or services.

Adoption of the standard impacted the Company’s results as follows (in thousands):



	Prior to ASC 606 Adoption			Adjustments for ASC 606			Subsequent to ASC 606 Adoption
	As of December 31, 2019
Consolidated Balance Sheets
Accounts receivable, net	$	324,416		$	—		$	324,416

	Year Ended December 31, 2019
Consolidated Statement of Comprehensive Income (Loss)
Net revenue	$	2,382,058		$	(71,641	)	$	2,310,417
Provision for doubtful accounts	(71,641		)	71,641			—
Operating loss	(319		)	—			(319		)
Consolidated Statements of Cash Flows
Changes in operating cash flows:
Accounts receivable, net	82,285			—			82,285

	As of December 31, 2018
Consolidated Balance Sheets
Accounts receivable, net	$	310,169		$	—		$	310,169

	Year Ended December 31, 2018
Consolidated Statement of Comprehensive Income (Loss)
Net revenue	$	2,001,132		$	(61,341	)	$	1,939,791
Provision for doubtful accounts	(61,341		)	61,341			—
Operating income	38,269			—			38,269
Consolidated Statements of Cash Flows
Changes in operating cash flows:
Accounts receivable, net	(21,012		)	—			(21,012		)

The following table presents the allowance for doubtful accounts for the years ended December 31, 2019, 2018 and 2017 (in thousands):



	Balance at Beginning of Period		Write-Off of Receivables			Charged to Costs and Expenses		Balance at End of Period
Year ended December 31, 2017
Allowance for doubtful accounts	$	32,144	$	(34,920	)	$	45,602	$	42,826
Year ended December 31, 2018
Allowance for doubtful accounts⁽¹⁾	$	—	$	—		$	—	$	—
Year ended December 31, 2019
Allowance for doubtful accounts ⁽¹⁾	$	—	$	—		$	—	$	—

(1) Subsequent to the adoption of ASC 606, an allowance for doubtful accounts is established only as a result of an adverse change in the Company’s payers’ ability to pay outstanding billings.

The following table sets forth the net revenue earned by category of payer for the years ended December 31, 2019, 2018 and 2017 (in thousands):



	Year Ended December 31,
	2019		2018		2017
Commercial payers	$	2,001,105	$	1,699,450	$	1,598,703
Government payers	285,128		217,876		203,651
Patients	24,184		22,465		25,692
Net revenue	$	2,310,417	$	1,939,791	$	1,828,046