Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Benefit

The income tax benefit is as follows (in thousands):

	Year Ended December 31,
	2021		2020
Current tax benefit - U. S. federal	$	—	$	4,473
Current tax benefit - state and local	636
Deferred tax benefit - U. S. federal	—		7,980
Deferred tax benefit - state and local	—		1,520
Total income tax benefit	$	636	$	13,973

Schedule of Deferred Tax Assets and Liabilities

The tax effects of temporary differences that give rise to significant portions of deferred tax assets and the deferred tax liability at December 31, 2021 and 2020 are presented below (in thousands):

	As of December 31,
	2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	32,281	$	27,441
Federal research and development tax credits	37,953		34,238
Share-based compensation	627		624
Capital loss carryforwards	41,144		41,399
Deferred rent	2		109
Accrued compensation	192		361
Charitable contributions	24		25
Leasehold improvements and equipment	1,292		1,648
Gross deferred tax assets	113,515		105,845
Less: valuation allowance	(113,515)		(105,272)
Total deferred tax assets	—		573
Deferred tax liability:
Capital gain on PRV	—		(573)
Net deferred tax assets	$	—	$	—

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of income taxes at the statutory federal income tax rate to net income tax benefit included in the accompanying consolidated statements of operations is set forth in the following table:

	Year Ended December 31,
	2021		2020
U.S. federal income tax benefit at the statutory rate	(21.00)	%	(21.00)	%
State income taxes, net of federal taxes	(1.38)		(50.50)
Loss in foreign subsidiary	—		(177.31)
Carry-back of federal net operating loss	—		(22.78)
Federal tax credits	(8.90)		(3.57)
Change in valuation allowance	26.53		201.18
Other	2.70		2.82
Effective income tax rate	(2.05)	%	(71.16)	%