The Company leases office and laboratory space in South San Francisco, California under a sub-sublease that expires in December 2023. The sub-sublease contains scheduled rent increases over the lease term. The Company also leases office space in Carmel, Indiana under a lease agreement that expires in August 2023. In February 2021, the Company subleased substantially all of the office space under the Carmel, Indiana lease. The Company also leased office and laboratory space in Groton, Connecticut that supported the Microbiome program under a lease that expired in June 2021. Due to the wind-down of the Microbiome program, the lease was not renewed. The Company’s China subsidiary leased office space and lab space in Shanghai, which the Company let expire in March 2021 and December 2020, respectively. The Company’s China subsidiary leases a registrational office in Shanghai under a lease that expires in May 2022. Additionally, the Company’s China subsidiary leases office space in Beijing under a lease agreement that expires in December 2021. Certain lease contracts contain renewal clauses that the Company assesses on a case-by-case basis. The Company also leases certain laboratory equipment accounted for as operating leases expiring at various dates, with the final lease expiring in 2024. In February 2021, the Company purchased substantially all of the leased equipment used for the Microbiome program from its leasing agency and sold this equipment to third parties (see Note 5).

When the Company cannot determine the implicit rate in its leasing arrangements, the Company uses its incremental borrowing rate as the discount rate when measuring operating lease liabilities. The incremental borrowing rate represents an estimate of the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease within a particular currency environment.

At September 30, 2021, the Company had operating lease liabilities of $7.2 million and ROU assets of $6.8 million.

The following summarizes quantitative information about the Company’s operating leases (in thousands):

	Three Months Ended September 30,					Nine Months Ended September 30,
	2021			2020		2021			2020
Lease cost
Operating lease cost	$	902		$	1,164	$	2,940		$	3,463
Short-term lease cost		32			101		227			301
Variable lease cost		312			409		1,063			1,101
Sublease income		(38	)		—		(104	)		—
Total lease cost	$	1,208		$	1,674	$	4,126		$	4,865

	Nine Months Ended September 30,
	2021		2020
Operating cash flows from operating leases	$	2,856	$	3,382
ROU assets exchanged for new operating lease liabilities	$	126	$	1,063

As of September 30, 2021 and December 31, 2020, the weighted-average remaining lease term for operating leases was 2.2 years and 2.7 years, respectively. As of September 30, 2021 and December 31, 2020, the weighted-average discount rate for operating leases was 9.7% and 9.2%, respectively.

As of September 30, 2021, the maturities of the Company’s operating lease liabilities were as follows (in thousands):

Three months ending December 31, 2021	$	927
Year Ending December 31, 2022		3,643
Year Ending December 31, 2023		3,491
Year Ended December 31, 2024		13
Total		8,074
Less: present value discount		(839	)
Operating lease liabilities	$	7,235