INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule reconciles the federal statutory tax rate to the effective income tax rate from continuing operations

The following table reconciles the federal statutory tax rate to the effective income tax rate from continuing operations:

	2021			2020			2019
Tax at statutory rate		21.0	%		21.0	%		21.0	%
State income tax, net of federal benefit		9.0			6.9			12.2
Federal and state tax credits		5.7			5.3			4.0
Stock-based compensation		(1.2	)		(0.5	)		(0.8	)
Net operating loss not benefitted		(5.4	)		(6.9	)		(5.8	)
Other		(0.2	)		(0.3	)		(0.2	)
Change in valuation allowance		(28.9	)		(25.5	)		(30.4	)
Effective tax rate		0.0	%		0.0	%		0.0	%

Schedule of significant components of the entity's deferred tax assets

. Significant components of our deferred tax assets are as follows:

	December 31,
	2021			2020
	(In thousands)
Net operating loss carryforwards	$	241,300		$	217,100
Federal and state tax credits		49,600			42,800
Capitalized research and development		6,900			6,000
Stock-based compensation		10,200			9,400
Operating lease liabilities		1,400			1,200
Other		2,600			2,100
Total deferred tax assets		312,000			278,600
Less: valuation allowance		(310,700	)		(277,200	)
Net deferred tax assets		1,300			1,400
Operating leases, right-of-use assets		(1,300	)		(1,400	)
Total deferred tax liabilities		(1,300	)		(1,400	)
Total net deferred tax assets	$	—		$	—

Schedule of reconciliation of the beginning and ending amounts of unrecognized tax benefits

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

Balance as of December 31, 2020	$	19,100
Decrease related to prior year tax positions		—
Increase related to current year tax positions		2,200
Balance as of December 31, 2021	$	21,300