Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Income before Income Taxes

Income before provision for income taxes was as follows:

	Year Ended December 31,
	2017		2016		2015
	(in thousands)
United States	$	144,100	$	188,078	$	95,644
Foreign	341,221		72,429		46,241
Income before income taxes	$	485,321	$	260,507	$	141,885

Components of Provision for Income Taxes

The components of provision for income taxes for all periods presented were as follows:

	Year Ended December 31,
	2017			2016			2015
	(in thousands)
Current tax provision:
Federal	$	54,245		$	54,315		$	52,557
State	(7,601		)	5,790			(1,576		)
Foreign	88,436			60,571			26,918
Total current	135,080			120,676			77,899
Deferred tax provision:
Federal	(153,963		)	(24,383		)	(37,669		)
State	(52,695		)	(14,080		)	(17,635		)
Foreign	(2,030		)	(8,384		)	(3,351		)
Total deferred	(208,688		)	(46,847		)	(58,655		)
Provision for income taxes	$	(73,608	)	$	73,829		$	19,244

Reconciliation of Provision for Income Taxes

A reconciliation of the provision for income taxes, with the amount computed by applying the statutory Federal income tax rate to income before income taxes is as follows:

	Year Ended December 31,
	2017			2016			2015
	(in thousands)
Expected tax expense at U.S. Federal statutory rate of 35%	$	169,860		$	91,179		$	49,658
State income taxes, net of Federal income tax effect	6,404			7,261			4,783
Foreign earnings at other than U.S. rates	(87,514		)	14,639			5,310
Federal and California R&D tax credits	(79,868		)	(41,144		)	(29,363		)
Excess tax benefits on stock-based compensation	(157,888		)	—			—
Tax Cuts and Jobs Act of 2017	79,077			—			—
Release of tax reserves on previously unrecognized tax benefits	—			—			(13,438		)
Other	(3,679		)	1,894			2,294
Provision for income taxes	$	(73,608	)	$	73,829		$	19,244
Effective Tax Rate	(15		)%	28		%	14		%

Deferred Tax Assets and Liabilities

The components of deferred tax assets and liabilities were as follows:

	As of December 31,
	2017			2016
	(in thousands)
Deferred tax assets:
Stock-based compensation	$	149,367		$	188,458
Accruals and reserves	34,170			29,231
Depreciation and amortization	(70,382		)	(93,760		)
Federal and California tax R&D credits	260,686			107,283
Federal foreign tax credits	102,242			—
Other	51,614			(2,363		)
Gross deferred tax assets	527,697			228,849
Valuation allowance	(49,431		)	(1,601		)
Net deferred tax assets	$	478,266		$	227,248

Summary of Changes in Unrecognized Tax Benefits

The aggregate changes in the Company’s total gross amount of unrecognized tax benefits are summarized as follows (in thousands):

Balances as of December 31, 2015	$	17,117
Increases related to tax positions taken during prior periods	1,047
Decreases related to tax positions taken during prior periods	(7,105		)
Increases related to tax positions taken during the current period	8,713
Decreases related to settlements with taxing authorities	(33		)
Balances as of December 31, 2016	19,739
Increases related to tax positions taken during prior periods	—
Decreases related to tax positions taken during prior periods	(3,226		)
Increases related to tax positions taken during the current period	26,389
Decreases related to expiration of statute of limitations	—
Balances as of December 31, 2017	$	42,902