REVENUE

6 Months Ended

Jun. 30, 2019

Revenue from Contract with Customer [Abstract]

Revenues by geographic region for the three and six months ended June 30, 2019 and 2018 were as follows:



	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(in thousands)
United States	$	121,618	$	101,396	$	231,912	$	197,656
China	91,868		54,182		170,008		110,395
Europe	38,343		41,454		85,589		77,450
Other Americas	28,082		33,112		53,811		60,852
Other Asia	30,413		38,318		74,221		73,109
Total revenues	$	310,324	$	268,462	$	615,541	$	519,462

The following tables represent our total revenues for the three and six months ended June 30, 2019 and 2018 by product type and interconnect protocol:



	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(in thousands)
ICs	$	53,046	$	28,934	$	113,669	$	57,521
Boards	120,643		136,708		229,073		254,759
Switch systems	73,808		57,074		155,866		112,721
Cables, accessories and other	62,827		45,746		116,933		94,461
Total revenues	$	310,324	$	268,462	$	615,541	$	519,462



	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(in thousands)
InfiniBand:
HDR	$	28,620	$	—	$	51,813	$	—
EDR	66,643		59,319		$	126,286	$	115,265
FDR	28,972		35,649		69,570		77,397
QDR/DDR/SDR	8,646		7,143		23,350		12,587
Total	132,881		102,111		271,019		205,249
Ethernet	169,131		157,470		330,024		294,418
Other	8,312		8,881		14,498		19,795
Total revenues	$	310,324	$	268,462	$	615,541	$	519,462

Contract balances

The Company recognizes contract liabilities, or deferred revenues, when it receives advance payments from customers before performance obligations primarily related to extended warranty and post-contract customer support have been performed. Advance payments are received at the beginning of the service period and the related deferred revenues are reclassified to revenue ratably over the service period. The balance of deferred revenues approximates the aggregate amount of the transaction price allocated to the unsatisfied performance obligations at the end of reporting period. The Company expects to recognize the long-term portion of deferred revenue over the remaining service period of up to five years.

The following table presents the significant changes in the deferred revenue balance during the six months ended June 30, 2019:



	(in thousands)
Balance, beginning of the period	$	39,223
New deferred revenue	21,013
Reclassification to revenues during the year (1)	(17,014		)
Balance, end of the period	43,222
Less: long-term portion of deferred revenue	20,224
Current portion, end of the period	$	22,998

(1) Of the total reclassification from deferred revenue to revenues, $11.7 million was related to the beginning balance, and $5.3 million was related to the new deferred revenue during the period.

Unsatisfied performance obligations, other than extended warranty and post-contract customer support, primarily represent contracts with future delivery dates. As of June 30, 2019, the Company had $57.5 million of unbilled transaction price allocated to performance obligations that were unsatisfied or partially unsatisfied related to contracts with an original duration over one year. The Company expects to invoice and recognize the revenue as it satisfies each performance obligation during a period of three years. The foregoing excludes the value of the remaining unsatisfied performance obligations related to contracts that have original durations of one year or less.

The Company recognizes assets for the material incremental costs of obtaining contracts with customers if it expects the benefit of those costs to be longer than one year. The Company allocates these assets proportionally to the performance obligations in the contracts and amortizes them as the performance obligations are satisfied. During the six months ended June 30, 2019, the Company recognized $11.3 million of assets related to costs to obtain contracts, and amortized $6.7 million of these assets during the same period. The unamortized balance of the assets was $4.6 million as of June 30, 2019.