Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and deferred tax liabilities as follows (in thousands):

	As of December 31,
	2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	46,346	$	43,973
Tax credits	5,262		4,535
California capitalized research and development	80		343
Fixed assets	8		—
Others, net	593		602
Total deferred tax assets	52,289		49,453
Valuation allowance	(52,289)		(49,403)
Deferred tax asset, net of valuation allowance	—		50
Deferred tax liabilities:
Others, net	—		—
Fixed assets	—		(50)
Total deferred tax liabilities	—		(50)
Net deferred tax assets	$	—	$	—

Schedule of Effective Income Tax Rate Reconciliation

Reconciliation between federal statutory tax rate and the effective tax rate is shown in the following table:

	2020		2019
Federal statutory income tax rate	21.00	%	21.00	%
Research and development credit	4.06	%	4.76	%
Nondeductible expense	0.64	%	(3.18)	%
Loss in joint venture	(11.70)	%	(7.44)	%
Foreign income tax rate difference	4.10	%	2.99	%
Others, net	(2.08)	%	(0.75)	%
Valuation allowance	(16.02)	%	(17.38)	%
Effective tax rate	—	%	—	%