The Company subleases certain office and laboratory space under a non-cancelable operating lease expiring in December 2024 for the initial leased space and December 2022 for expansion space leased pursuant to an amendment to the lease agreement entered into in August 2018. The sublease agreement included options to extend for the entire premises through October 2028. The options to extend must be exercised prior to the termination of the original lease agreement. The period covered by the options was not included in the non-cancellable lease term as it not was not determined to be reasonably certain to be executed. The lease agreement also includes a one-time termination option for the expansion space only whereby the Company can terminate the lease with advance written notice. The termination option was not determined to be reasonably certain to be executed. The lease is subject to charges for common area maintenance and other costs, and base rent is subject to an annual 3% increase each subsequent year. Costs determined to be variable and not based on an index or rate were not included in the measurement of the operating lease liabilities.

Monthly rent expense is recognized on a straight-line basis over the term of the lease. The operating lease is included in the balance sheet at the present value of the lease payments at a 7% discount rate using the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment as the leases do not provide an implicit rate. The weighted average remaining lease term was 4.5 years.

	Three months ended September 30, 2019		Nine months ended September 30, 2019

Operating lease cost	$	753	$	2,258
Variable lease cost		374		1,126
Short-term lease cost		13		42
Total lease cost	$	1,140	$	3,426

Cash paid for amounts included in the measurement of operating lease liabilities for the three and nine months ended September 30, 2019 was $0.7 million and $2.2 million, respectively.

Gross future minimum annual rental commitments as of September 30, 2019, were as follows (in thousands):

	Undiscounted Rent Payments
Year ending December 31,
2019 (remaining 3 months)	$	739
2020		3,038
2021		3,127
2022		3,220
2023		1,694
2024		1,745
Total undiscounted rent payments	$	13,563

Present value discount		(1,930	)
Present value	$	11,633
Current portion of operating lease liability (included as a component of accrued expenses)	$	2,291
Noncurrent operating lease liabilities		9,342
Total operating lease liability	$	11,633

Future minimum lease payments under non-cancelable operating leases at December 31, 2018 were as follows (in thousands):

Years ending December 31,
2019	$	2,944
2020		3,035
2021		3,123
2022		3,216
2023		1,690
Thereafter		1,741
	$	15,749

For the three and nine months ended September 30, 2018 the Company recorded approximately $0.6 million and $1.5 million, respectively, in rent expense.

The Company is not a party to any material legal proceedings and is not aware of any pending or threatened claims. From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities.