Revenue Recognition

Contract Balances

The following table summarizes the opening and closing balances of the Company's accounts receivable, net; contract asset, current; contract asset, non-current; deferred revenue, current; and deferred revenue, non-current (in thousands):



	Accounts receivable, net		Contract asset, current		Contract asset, non-current		Deferred revenue, current		Deferred revenue, non-current
Beginning balances as of January 1, 2018 ⁽¹⁾	$	576,313	$	9,002	$	16,186	$	71,085	$	53,101
Closing balances as of December 31, 2018	630,119		9,778		16,396		73,142		46,641
Increase/(decrease)	$	53,806	$	776	$	210	$	2,057	$	(6,460	)


⁽¹⁾	Includes cumulative adjustments made to these accounts on January 1, 2018 from the adoption of Topic 606.

The difference between the opening and closing balances of the Company's accounts receivable, net, contract assets and deferred revenues primarily results from the timing difference between the satisfaction of the Company's performance obligation and the customer's payment, as well as business combinations closed during the year ended December 31, 2018. The amounts of revenue recognized during the year ended December 31, 2018 from the opening deferred revenue balance was approximately $81.8 million. For the year ended December 31, 2018, no impairment loss related to contract balances was recognized in the consolidated statement of operations.

Contract Costs

The ending balance of net capitalized contract costs as of December 31, 2018 was $188.2 million, which was included in other assets in the consolidated balance sheet. For the year ended December 31, 2018, $73.1 million of contract costs were amortized, which were included in sales and marketing expense in the consolidated statement of operations.

Remaining performance obligations

As of December 31, 2018, approximately $5.8 billion of total revenues and deferred installation revenues are expected to be recognized in future periods, the majority of which will be recognized over the next 24 months. While initial contract terms vary in length, substantially all contracts thereafter automatically renew in one-year increments. Included in the remaining performance obligations is either 1) remaining performance obligations under the initial contract terms or 2) remaining performance obligations related to contracts in the renewal period once the initial terms have lapsed. The remaining performance obligations do not include variable consideration related to unsatisfied performance obligations such as the usage of metered power or any contracts that could be terminated without any significant penalties such as the majority of interconnection revenues. The remaining performance obligations above exclude approximately $1.2 billion total revenues to be recognized in the future related to arrangements where the Company is the lessor.