Contract assets

as of June 30, 2019 and December 31, 2018 were $

2,883

and $

3,624

, respectively, and included in other current assets.

A rollforward of the Company’s deferred revenue and customer advances is as follows:


	Six Months Ended June 30, 2019
Beginning balance, January 1 (1)	$	17,474
Deferred revenue and customer advances assumed in ESI Merger		4,629
Additions to deferred revenue and customer advances		34,772
Amount of deferred revenue and customer advances recognized in income		(27,407	)

Ending balance, June 30 (2)	$	29,468

(1)	Beginning deferred revenue and customer advances as of January 1, 2019 included $ 8,134 of current deferred revenue, $ 3,228 of long-term deferred revenue and $ 6,112 of current customer advances.

(2)	Ending deferred revenue as of June 30, 2019 included $ 17,968 of current deferred revenue, $ 2,871 of long-term deferred revenue and $ 8,629 of current customer advances.

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers:


	Three Months Ended June 30, 2019
	Vacuum & Analysis		Light & Motion		Equipment & Solutions		Total
Net revenues:
Products	$	191,760	$	167,363	$	42,203	$	401,326
Services		43,895		15,216		13,673		72,784

Total net revenues	$	235,655	$	182,579	$	55,876	$	474,110


	Three Months Ended June 30, 2018
	Vacuum & Analysis		Light & Motion		Equipment & Solutions		Total
Net revenues:
Products	$	321,454	$	188,545	$	—	$	509,999
Services		46,874		16,267		—		63,141

Total net revenues	$	368,328	$	204,812	$	—	$	573,140


	Six Months Ended June 30, 2019
	Vacuum & Analysis		Light & Motion		Equipment & Solutions		Total
Net revenues:
Products	$	384,408	$	346,060	$	68,221	$	798,689
Services		85,602		30,507		22,873		138,982

Total net revenues	$	470,010	$	376,567	$	91,094	$	937,671


	Six Months Ended June 30, 2018
	Vacuum & Analysis		Light & Motion		Equipment & Solutions		Total
Net revenues:
Products	$	625,790		380,886	$	—	$	1,006,676
Services		90,882		29,857		—		120,739

Total net revenues	$	716,672	$	410,743	$	—	$	1,127,415

Product revenue, excluding revenue from certain custom products, is recorded at a point in time, while the majority of the service revenue and revenue from certain custom products is recorded over time.

Refer to Note 17 for revenue by reportable segment, geography and groupings of similar products.