We have operating leases for office space, automobiles, and other equipment in the United States and in various international locations in which we do business. We also have other contracts such as, manufacturing agreements and service agreements, which we review to determine if they contain an embedded lease. We specifically review these other contracts to determine whether we have the right to substantially all of the economic benefit from the use of any specified assets or the right to direct the use of any specified assets, either of which would indicate the existence of a lease.

As of March 31, 2019, our leases have remaining lease terms of one month to six years, some of which include options to extend the leases for up to 3 years, and some of which include options to terminate the leases within 3 months. For those leases that are reasonably assured to be renewed, we have included the option to extend as part of our right of use asset and right of use liability included on the Consolidated Balance Sheet. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term. Lease expense related to these short-term leases was $0.2 million for the three months ended March 31, 2019, and is included in selling, general and administrative expenses on the Consolidated Statement of Income. For lease agreements entered into or reassessed after the adoption of Topic 842, we elected the practical expedient which allows us to not separate lease and non-lease components. None of our lease agreements contain any material residual value guarantees or material restrictive covenants.

Supplemental balance sheet information related to operating leases is as follows:

		March 31,		January 1,
(In thousands)	Classification	2019		2019
Assets
Operating lease asset	Other assets	$	9,502	$	10,322
Total lease assets		$	9,502	$	10,322

Liabilities
Current operating lease liability	Accrued expenses	$	2,718	$	2,948
Non-current operating lease liability	Other non-current liabilities		6,801		7,374
Total lease liability		$	9,519	$	10,322

The components of lease expense included in the Consolidated Statement of Income for the three months ended March 31, 2019 are as follows:

(In thousands)	Classification	Three Months Ended March 31, 2019
Operating lease expense	Selling, general and administrative expenses	$	349
Operating lease expense	Research and development expenses		454
Operating lease expense	Cost of sales		16
Total lease expense		$	819

As of March 31, 2019, the maturity of lease liabilities included on the Consolidated Balance Sheet are as follows:

(In thousands)	Amount
Remainder of 2019	$	2,363
2020		2,185
2021		2,032
2022		1,544
2023		1,163
Thereafter		747
Total lease payments		10,034
Less: Interest		(515	)
Present value of lease liabilities	$	9,519

Operating lease payments include $1.2 million related to options to extend lease terms that are reasonably certain of being exercised and there are no legally binding leases that have not yet commenced.

As of December 31, 2018, future minimum rental payments under non-cancelable operating leases, including renewals determined to be reasonably assured as of December 31, 2018, with original maturities of greater than 12 months are as follows:

(In thousands)	Amount (1)
2019	$	3,873
2020		3,580
2021		2,771
2022		2,053
2023		1,317
Thereafter		762
Total	$	14,356

Our leases do not provide an implicit borrowing rate and therefore we use an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. We used the incremental borrowing rate on January 1, 2019, for operating leases that commenced on or prior to that date. The incremental borrowing rate was determined on a portfolio basis by grouping leases with similar terms as well as grouping leases based on a U.S. dollar or Euro functional currency. The actual rate is then determined based on a credit spread over LIBOR as well as the Bloomberg Curve Matrix for the U.S. Communications section.

	As of March 31, 2019
Weighted average remaining lease term (years)
Operating leases with USD functional currency		3.0
Operating leases with Euro functional currency		5.1
Weighted average discount rate
Operating leases with USD functional currency		4.61	%
Operating leases with Euro functional currency		1.85	%

(In thousands)	As of March 31, 2019
Cash paid for amounts included in the measurement of lease liabilities / assets
Cash used in operating activities related to operating leases		$ (811	)

Right-of-use assets obtained in exchange for lease obligations		$ 10,387

We are the lessor in sales-type lease arrangements for network equipment, which have initial terms of up to five years. Our sales-type lease arrangements contain either a provision whereby the network equipment reverts back to us upon the expiration of the lease or a provision that allows the lessee to purchase the network equipment at a bargain purchase amount. In addition, our sales-type lease arrangements do not contain any residual value guarantees or material restrictive covenants. The allocation of the consideration between lease and non-lease components is determined by standalone sales price by component. The net investment in sales-type leases consists of lease receivables less unearned income. Collectability of sales-type leases is evaluated periodically at an individual customer level. At March 31, 2019 and December 31, 2018, we had no allowance for credit losses for our net investment in sales-type leases. As of March 31, 2019 and December 31, 2018, the components of the net investment in sales-type leases were as follows:

	March 31,		December 31,
(In thousands)	2019		2018
Current minimum lease payments receivable (included in other receivables)	$	9,349	$	11,339
Non-current minimum lease payments receivable (included in other assets)		1,494		1,670
Total minimum lease payments receivable		10,843		13,009
Less: Current unearned revenue		573		631
Less: Non-current unearned revenue		343		473
Net investment in sales-type leases	$	9,927	$	11,905

The components of sales-type lease gross profit recognized at the lease commencement date and interest income, included in the Consolidated Statement of Income for the three months ended March 31, 2019 are as follows:

(In thousands)	Classification	Three Months Ended March 31, 2019
Sales type leases	Sales - products	$	1,512
Sales type leases	Cost of sales - products		591
Sales type leases	Gross profit	$	921

Sales type leases	Interest and dividend income	$	87

Future minimum lease payments to be received from sales-type leases as of March 31, 2019 are as follows:

(In thousands)	Amount ⁽¹⁾
Remainder of 2019	$	9,005
2020		1,056
2021		493
2022		209
2023		78
Thereafter		2
Total	$	10,843