Deferred Revenue

Deferred revenue consisted of the following (in thousands):



	As of March 31, 2018		As of December 31, 2017*
Product, subscription and support, current	$	489,264	$	496,218
Professional services, current	44,276		50,397
Total deferred revenue, current	533,540		546,615
Product, subscription and support, non-current	352,269		363,313
Professional services, non-current	327		172
Total deferred revenue, non-current	352,596		363,485
Total deferred revenue	$	886,136	$	910,100

Changes to the unearned revenue during the three months ended March 31, 2018 are as follows (in thousands):



	As of December 31, 2017*		Billings for the quarter		Revenue Recognized			As of March 31, 2018
Deferred Revenue	$	910,100	$	175,106	$	(199,070	)	$	886,136

Remaining Performance Obligations

Transaction price allocated to remaining performance obligations represents contracted revenue that has not yet been recognized, which includes deferred revenue and non-cancelable contracts that will be invoiced and recognized as revenue in future periods ("backlog"). While deferred revenue is recorded on our balance sheet as a liability, backlog is not recorded in revenue, unearned revenue or elsewhere in our consolidated financial statements until we establish a contractual right to invoice at which point they are recorded as revenue or deferred revenue as appropriate. As of March 31, 2018, the aggregate amount of the transaction price allocated to remaining performance obligations was $886.1 million in deferred revenue and $11.6 million in backlog. We have used the practical expedient to not disclose backlog related to the comparative period under ASC 606.

We expect that the amount of backlog relative to the total value of our contracts will change from year to year due to several factors, including the amount invoiced early in the contract term, the timing and duration of customer agreements, varying invoicing cycles of agreements and changes in customer financial circumstances. Accordingly, we believe that fluctuations in backlog are not always a reliable indicator of future revenues and we do not utilize backlog as a key management metric internally.

We expect to recognize these remaining performance obligations as follows (in percentages):



	Total	Less than 1 year	1-2 years	2-3 years	More than 3 years
Deferred revenue	100%	60%	25%	11%	4%
Backlog	100%	38%	50%	12%	—%

*Certain prior period amounts have been adjusted as a result of adoption of the new revenue recognition standard.