NOTE 8. REVENUE

As of June 30, 2019, we had a total of $8.2 million of deferred service revenue from our service contracts, $6.7 million of which was recorded as “Deferred service revenue, current” to be recognized over the next year and the remaining $1.5 million was recorded as “Deferred service revenue, non-current” to be recognized in the next 2 to 4 years. Revenue recorded in the three and six months ended June 30, 2019 includes $1.9 million and $4.3 million, respectively, of previously deferred revenue that was included in “Deferred service revenue, current” as of December 31, 2018. Contract assets as of June 30, 2019 and December 31, 2018 were not material.

As of June 30, 2019, we had a total of $0.4 million of deferred commissions included in “Prepaid expenses and other current assets” which is recognized as the related revenue is recognized. Additionally, as a practical expedient, we expense costs to obtain a contract as incurred if the amortization period would have been a year or less.

A summary of our revenue by geographic location for the three and six months ended June 30, 2019 and 2018 is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
North America	$	14,222	$	9,204	$	23,209	$	17,015
Europe (including the Middle East and Africa)		3,414		3,687		6,478		7,700
Asia Pacific		6,985		8,687		11,359		16,225
Total	$	24,621	$	21,578	$	41,046	$	40,940

A summary of our revenue by category for the three and six months ended June 30, 2019 and 2018 is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2019		2018		2019		2018
Instrument revenue	$	12,664	$	8,525	$	18,287	$	15,669
Consumable revenue		8,586		9,960		16,420		19,098
Product revenue		21,250		18,485		34,707		34,767
Service and other revenue		3,371		3,093		6,339		6,173
Total revenue	$	24,621	$	21,578	$	41,046	$	40,940