CONTRACT BALANCES

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Contract Balances

CONTRACT BALANCES

The allowance for doubtful accounts as of September 30, 2018, and changes in the allowance for doubtful accounts during the nine months ended September 30, 2018, were as follows (in thousands):

	Nine Months Ended September 30, 2018
Balance, beginning of period	$	8,602
Add: bad debt expense	19,285
Less: write-offs, net of recoveries	(19,002		)
Balance, end of period	$	8,885

Contract liabilities consist of deferred revenue, which is recorded on the consolidated balance sheets when the Company has received consideration, or has the right to receive consideration, in advance of the transfer of the performance obligations of the contract to the customer.

As of September 30, 2018, deferred revenue was $3.4 million, the majority of which is expected to be recognized as revenue in the subsequent three-month period ending December 31, 2018. Changes in deferred revenue during the nine months ended September 30, 2018 were as follows (in thousands):

	Nine Months Ended September 30, 2018
Balance, beginning of period	$	3,469
Less: Recognition of deferred revenue from beginning balance	(3,132		)
Add: Net increase in current period contract liabilities	3,055
Balance, end of period	$	3,392

No other contract assets or liabilities are recorded on the Company's condensed consolidated balance sheets as of September 30, 2018 and December 31, 2017.