Leases

3 Months Ended

Mar. 31, 2021

Leases [Abstract]

Leases

Note 6. Leases

In July 2017, the Company entered into a lease of office and laboratory space for its headquarters at 490 Arsenal Way, Suite 200 in Watertown, Massachusetts (the “Watertown Lease”). The Watertown Lease commenced in April 2018 with rent commencing in May 2018. The lease has a non-cancelable term of ten years with an option to extend for one additional five-year period and is subject to rent escalation throughout the term and requires the Company to provide collateral in the amount of $2.6 million, which is recorded as restricted cash on the accompanying condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020.

The elements of lease costs were as follows (in thousands):

	Three Months Ended March 31,
	2021		2020
Lease cost:
Operating lease cost	$	637	$	637
Variable lease cost		241		266
Total lease cost		878		903

The following table summarizes the lease term and discount rate applied in arriving at the lease liability:

	March 31, 2021			December 31, 2020
Remaining lease term	7.0 years			7.3 years
Discount rate		10	%		10	%

Future lease payments under non-cancelable leases as of March 31, 2021 for each of the years ending December 31 are as follows (in thousands):

Undiscounted lease payments:
Remaining 2021	$	1,704
2022		2,340
2023		2,410
2024		2,483
2025		2,557
Thereafter		6,277
Total undiscounted lease payments		17,771
Less: imputed interest		(5,153	)
Total operating lease liability	$	12,618