Income taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule Components of Loss Before Income Taxes

The components of loss before income taxes were as follows (in thousands):

	Year ended December 31,
	2021		2020		2019
Domestic	$	(292,213)	$	(120,114)	$	(320,594)
Foreign	—		—		—
Total	$	(292,213)	$	(120,114)	$	(320,594)

Reconciliation of Income Tax Provision (Benefit) Computed at the Statutory Federal Income Tax Rate to Effective Income Tax Rate (Provision) Benefit as Reflected in the Financial Statements

	Year ended December 31,
	2021		2020		2019
Federal income tax expense at statutory rate	21.0	%	21.0	%	21.0	%
State income tax, net of federal benefit	0.6	%	3.8	%	5.5	%
Permanent differences	—	%	0.3	%	(0.1)	%
Stock-based compensation	0.3	%	(4.1)	%	(0.5)	%
Research and development credit	0.2	%	13.8	%	5.6	%
Officer compensation limitation	(0.4)	%	(1.6)	%	(0.7)	%
Uncertain tax positions	—	%	(1.1)	%	(0.4)	%
Other	(1.1)	%	—	%	(0.2)	%
Change in valuation allowance	64.8	%	(32.1)	%	(30.2)	%
Separation adjustment	(85.4)	%	—	%	—	%
Effective income tax rate (expense) benefit	—	%	—	%	—	%

Components of Deferred Tax Assets and Liabilities

	Year ended December 31,
	2021		2020
Deferred tax assets:
U.S. net operating loss carryforwards (federal and state)	$	12,142	$	149,570
Tax credit carryforwards (federal and state)	466		49,379
Capitalized license fees and research and development expenses	11,905		13,091
Deferred revenue	13,724		15,348
Stock-based compensation	15,824		21,400
Lease liabilities	71,941		34,119
Accruals and other	5,395		2,715
Total deferred tax assets	131,397		285,622
Intangible assets	(476)		(1,509)
Right-of-use assets	(69,693)		(31,139)
Fixed assets	(2,958)		(5,477)
Less: valuation allowance	(58,270)		(247,497)
Net deferred taxes	$	—	$	—

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

	Unrecognized tax benefits
Balance as of December 31, 2019	$	3,070
Increases (decreases) for tax positions related to current period	1,333
Increases (decreases) for tax positions related to prior periods	—
Balance as of December 31, 2020	4,403
Increases (decreases) for tax positions related to current period	36
Increases (decreases) for tax positions as part of separation adjustment	(4,403)
Balance as of December 31, 2021	$	36