The Company has established its primary research facility in 8,215 square feet of leased office and laboratory space in Oceanside, California. The current lease for this facility expires in December 2021, with the Company’s option to terminate the lease on January 1, 2020 upon a six-month advanced notice. The current base rent is approximately $10,000 per month. The facility has leasehold improvements which include cGMP (current Good Manufacturing Practices) level clean rooms designed for the derivation of clinical-grade stem cells and their differentiated derivatives, research laboratories for the Company’s stem cell differentiation studies and segregated rooms for biohazard control and containment of human donor tissue. The monthly base rent will increase by 3% annually on the anniversary date of the agreement.

The Company leases a 13,320 square foot manufacturing facility in Frederick, Maryland, which is used for laboratory and administrative purposes. As of March 31, 2019, the base rent was approximately $17,000 per month. The lease was amended in October 2018 to increase the square footage from 8,280 square feet to 13,320 for an additional 5,040 square feet. In addition, the Company extended the lease to expire in November 2025. The administration space is used to support sales, marketing and accounting. The laboratory is being used to develop and manufacture the Company’s research products. The manufacturing laboratory space has clean rooms and is fitted with the necessary water purification systems, temperature-controlled storage, labeling equipment and other standard manufacturing equipment to manufacture, package, test, store, and distribute cell culture products.

On February 25, 2011, the Company entered into a lease agreement (the “Lease Agreement”) with S Real Estate Holdings LLC to allow the Company to expand into new corporate offices located at 5950 Priestly Drive, Carlsbad, California. The building is used for administrative purposes, but could also be used for research and development purposes if such space is needed in the future. The lease initially covered approximately 4,653 square feet, starting on March 1, 2011, and was amended to cover approximately 8,199 square feet effective July 1, 2011, and to cover approximately 9,848 square feet effective January 1, 2013. The lease expired on February 29, 2016, and the Company extended the term of the lease for one year. On February 22, 2017, the Company extended the term of the lease for an additional three years. The Company began paying rent at an initial rate of approximately $5,000 per month and the rate was amended effective July 1, 2011 and January 1, 2013 to account for additional square footage occupied by the Company. As of March 31, 2019, the base rent is approximately $13,000 per month. The monthly base rent will increase by 3% annually on the anniversary date of the agreement. The Company is also obligated to pay a portion of the utilities for the building and increases in property tax and insurance.

S Real Estate Holdings LLC is owned by Dr. Russell Kern, the Company’s Executive Vice President and Chief Scientific Officer and a director, and was previously owned by Dr. Andrey Semechkin, the Company’s Chief Executive Officer and Co-Chairman of the Board of Directors. The Lease Agreement was negotiated at arm’s length and was reviewed by the Company’s outside legal counsel. The terms of the lease were reviewed by a committee of independent directors, and the Company believes that, in total, those terms are consistent with the terms that could be obtained for comparable facilities from an unaffiliated party.

These operating leases are included in "right-of-use asset" on the Company's March 31, 2019 balance sheet and represent the Company’s right to use the underlying asset for the lease term. The Company’s obligation to make lease payments is included in ”operating lease liabilities, current” and “operating lease liabilities, net of current portion” on the Company's March 31, 2019 balance sheet. Operating lease right-of-use assets and liabilities commencing after January 1, 2019 are recognized at commencement date based on the present value of lease payments over the lease term. As of March 31, 2019, total right-of-use assets and operating lease liabilities were approximately $933,000 and $1,305,000, respectively. All operating lease expense is recognized on a straight-line basis over the lease term.

Because the rate implicit in each lease is not readily determinable, the Company uses its incremental borrowing rate to determine the present value of the lease payments.

Information related to the Company's right-of-use assets and related lease liabilities were as follows (in thousands):

	Three months ended March 31, 2019
Cash paid for operating lease liabilities	$	119
Right-of-use assets obtained in exchange for new operating lease obligations	$	933
Weighted-average remaining lease term (years)		5.16
Weighted average discount rate		17.38	%

Maturities of lease liabilities as of March 31, 2019 were as follows :
2019 (remaining months)	$	372
2020		369
2021		347
2022		220
2023		227
Thereafter		454
		1,989
Less: present value adjustments		(684	)
Total lease liabilities	$	1,305

Current operating lease liabilities	$	294
Non-current operating lease liabilities		1,011
Total operating lease liabilities	$	1,305

The Company incurred rent expense of $140,000 and $87,000 for the three months ended March 31, 2019 and 2018, respectively.

During the three months ended March 31, 2019 and 2018, for the biomedical market segment, one customer accounted for 42% and 37% of consolidated revenues, respectively. No other single customer accounted for more than 10% of revenues for any period presented.

During the three months ended March 31, 2019 and 2018, no single vendor accounted for more than 10% of consolidated purchases.