Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Table Text Blocks

Schedule of the components of the provision for (benefit from) income taxes

	Year Ended December 31,
	2022		2021		2020
Current taxes:
Federal	$	—	$	—	$	—
State		11,618		5,503		2,685
Total current taxes		11,618		5,503		2,685
Deferred taxes:
Federal		52,191		(251,367)		—
State		13,548		(81,927)		—
Total deferred taxes		65,739		(333,294)		—

Income tax expense (benefit) $ 77,357 $ (327,791) $ 2,685

Reconciliation of income taxes from continuing operations computed using U.S. federal statutory rate to that reflected in operations

	Year Ended December 31,
	2022		2021		2020
Income tax expense using U.S. federal statutory rate	$	53,009	$	42,138	$	22,861
Permanent differences		(290)		426		325
State income taxes, net of federal benefit		16,160		12,554		7,565
Executive compensation - Section 162(m)		2,654		695		1,718
Excess tax benefits		3,613		6,270		5,132
Fair market valuation of Note Hedge Warrants and Convertible Note Hedges		(50)		325		1,680
Tax credits		(252)		(9)		(3,149)
Expiring net operating losses and tax credits		1,087		491		1,991
Effect of change in state tax rate on deferred tax assets and deferred tax liabilities		2,581		123		(208)
Change in the valuation allowance		(1,155)		(390,804)		(35,230)
Income tax expense (benefit)	$	77,357	$	(327,791)	$	2,685

Schedule of components of deferred tax assets and liabilities

	December 31,
	2022		2021
Deferred tax assets:
Net operating loss carryforwards	$	88,769	$	165,022
Tax credit carryforwards		59,290		60,125
Capitalized research and development		12,683		4,981
Share-based compensation		13,666		16,857
Basis difference on collaboration agreement for North America with AbbVie		95,460		78,194
Accruals and reserves		5,935		5,003
Basis difference on Convertible Notes		2,845		8,166
Intangible assets		5,299		5,396
Operating lease liability		5,337		5,971
Other		1,242		3,997
Total deferred tax assets		290,526		353,712
Deferred tax liabilities:
Basis difference on Convertible Notes		—		(11,960)
Operating lease right-of-use assets		(3,810)		(4,248)
Total deferred tax liabilities		(3,810)		(16,208)
Net deferred tax asset		286,716		337,504
Valuation allowance		(3,055)		(4,210)
Net deferred tax asset	$	283,661	$	333,294

Summary of changes in the unrecognized tax benefits

	December 31,
	2022		2021		2020
Balance at the beginning of the period	$	84,606	$	68,087	$	53,099
Increases based on tax positions related to the current period		101,225		83,206		66,687
Decreases for tax positions in prior periods		(83,206)		(66,687)		(51,699)
Balance at the end of the period	$	102,625	$	84,606	$	68,087