INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2020

Summary of components of loss before income taxes

The components of loss before income taxes for the years ended December 31, 2020 and 2019, are as follows (in thousands):

		2020		2019
Loss subject to domestic income taxes	$	(719,636)	$	(277,244)
Loss subject to foreign income taxes		68		(90)
	$	(719,568)	$	(277,334)

Summary of income tax provision/(benefit)

The Company recorded an income tax provision/(benefit) of $(0.19) million and $0.03 million in connection with its domestic state and foreign subsidiaries for the years ended December 31, 2020 and 2019, respectively, as follows (in thousands):

	2020		2019
Current
Federal	$	—	$	—
State		5		2
Foreign		(193)		23
Total current tax expense (benefit)	$	(188)	$	25
Deferred
Federal	$	—	$	—
State		—		—
Foreign		—		—
Total deferred tax expense (benefit)	$	—	$	—
Total income tax expense (benefit)	$	(188)	$	25

Summary of components of deferred taxes

Significant components of the Company’s deferred taxes as of December 31, 2020 and 2019, are as follows (in thousands):

	2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	265,799	$	139,899
Tax credit carryforwards		40,454		18,076
Share-based compensation expense		2,554		4,191
Depreciation		499		210
Accrued compensation and vacation		2,498		699
Interest		489		409
Tenant improvement allowance		8,777		7,757
Accruals and reserves		39,502		3,577
Other		1		—
Total deferred tax assets		360,573		174,818
Valuation allowance		(360,573)		(174,818)
Net deferred tax assets		—		—
Net deferred tax assets (liabilities)	$	—	$	—

Summary of reconciliation of taxes at the federal statutory rate to our provision for income taxes

	Year Ended December 31,
	2020		2019
Statutory federal income tax rate	21.0	%	21.0	%
Share-based compensation	(0.2)		(0.2)
Mark-to-market adjustment	(3.4)		(1.1)
Nondeductible expenses	(0.1)		(0.8)
Tax credits	2.8		1.9
Change in valuation allowance	(20.1)		(20.8)
Provision for income taxes	—	%	—	%

Summary of activity related to unrecognized tax benefits

The following table summarizes the activity related to unrecognized tax benefits for the years ended December 31, 2020 and 2019 (in thousands):

	December 31,
	2020		2019
Unrecognized benefit – beginning of period	$	20,635	$	11,647
Gross increases – prior-period tax positions		21		4
Gross decreases – prior-period tax positions		(2)		—
Gross increases – current-period tax positions		22,382		8,995
Gross decrease – current-period tax positions		—		(11)
Statute lapse		(142)		—
Unrecognized benefit – end of period	$	42,894	$	20,635

Summary of interest expense and penalty expense related to the unrecognized tax benefits

Related to the unrecognized tax benefits above, the Company recognized interest expense and penalty expense as part of income tax expenses in the consolidated statements of operations according to the following table (in thousands):

	Year Ended December 31,
	2020		2019
Interest expense	$	(45)	$	16
Penalty expense		(20)		1