Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

Schedule of Additional Information Related to Operating Leases

The following table contains additional information related to the Company’s operating leases:

Location	Approximate Square Footage	Commencement Dates	Expiration Dates
Seattle, WA	48,086	March 2019 to September 2020	December 2026 to April 2028
Cambridge, MA	59,639	March 2019 to May 2020	November 2025 to February 2028
South San Francisco, CA	66,075	December 2019 to November 2021	April 2024 to April 2030
Fremont, CA	163,193	July 2021	November 2031

Summary of Lease Costs

The following table summarizes the Company’s lease costs:

	Year Ended December 31,
	2021		2020		2019
	(in thousands)
Operating lease cost	$	16,425	$	10,757	$	4,898
Short-term lease cost		512		1,886		3,710
Variable lease cost		5,230		3,081		1,494
Total lease cost	$	22,167	$	15,724	$	10,102

Reconciliation of Undiscounted Operating Lease Cash Flows by Fiscal Year to Present Value of Operating Lease Liabilities

The following table reconciles the Company’s undiscounted operating lease cash flows by fiscal year to the present value of the operating lease liabilities as of December 31, 2021 (in thousands):

2022		19,954
2023		21,511
2024		20,601
2025		20,449
2026		17,701
2026 and thereafter		80,913
Total undiscounted lease payments		181,129
Less: imputed interest		(66,291	)
Less: tenant improvement allowances		(3,895	)
Present value of operating lease liabilities	$	110,943