Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Expense (Benefit), Continuing Operations [Abstract]

Schedule of income before income tax

Income (loss) before taxes consisted of the following:

	Years Ended December 31,
	2017			2016			2015
	(In thousands)
Domestic	$	46,031		$	38,211		$	58,498
Foreign	(5,042		)	(15,574		)	1,733
	$	40,989		$	22,637		$	60,231

Components of provision for (benefit from) income taxes

The provision for (benefit from) income taxes is comprised of:

	Years Ended December 31,
	2017			2016			2015
	(In thousands)
Federal:
Current	$	20,661		$	22,115		$	20,497
Deferred	43,678			(2,198		)	(170,798		)
State:
Current	495			884			609
Deferred	(43		)	(271		)	(1,933		)
Foreign:
Current	1,101			1,275			443
Deferred	(2,041		)	(5,988		)	25
	$	63,851		$	15,817		$	(151,157	)

Schedule of effective income tax rate reconciliation

The differences between Rambus’ effective tax rate and the U.S. federal statutory regular tax rate are as follows:

	Years Ended December 31,
	2017		2016		2015
Expense at U.S. federal statutory rate	35.0	%	35.0	%	35.0	%
Expense (benefit) at state statutory rate	0.7		1.8		(1.5	)
Withholding tax	50.1		97.0		34.1
Foreign rate differential	2.8		4.1		0.4
Research and development (“R&D”) credit	(3.9	)	(8.3	)	(2.3	)
Executive compensation	1.8		1.5		0.5
Stock-based compensation	14.9		34.8		5.3
Foreign tax credit	(50.1	)	(97.0	)	(34.1	)
Impact of corporate rate change on deferred taxes	50.6		—		—
Other	1.4		1.0		(0.6	)
Valuation allowance	52.5		—		(287.8	)
	155.8	%	69.9	%	(251.0	)%

Components of the net deferred tax assets

The components of the net deferred tax assets are as follows:

	As of December 31,
	2017			2016
	(In thousands)
Deferred tax assets:
Depreciation and amortization	$	10,840		$	22,348
Other timing differences, accruals and reserves	8,766			12,268
Deferred equity compensation	7,979			17,426
Net operating loss carryovers	16,335			11,439
Tax credits	157,051			120,660
Total gross deferred tax assets	200,971			184,141
Convertible debt	(791)			(3,870)
Total net deferred tax assets	200,180			180,271
Valuation allowance	(50,911		)	(23,529		)
Net deferred tax assets	$	149,269		$	156,742

	As of December 31,
	2017			2016
	(In thousands)
Reported as:
Non-current deferred tax assets	$	159,099		$	168,342
Non-current deferred tax liabilities	(9,830		)	(11,600		)
Net deferred tax assets	$	149,269		$	156,742

Summary of valuation allowance

The following table presents the tax valuation allowance information for the years ended December 31, 2017, 2016 and 2015:

	Balance at Beginning of Period		Charged (Credited) to Operations	Charged to Other Account*	Valuation Allowance Release		Valuation Allowance Set up	Balance at End of Period
Tax Valuation Allowance
Year ended December 31, 2015	$	193,874	—	1,299	(174,456	)	—	$	20,717
Year ended December 31, 2016	$	20,717	—	2,812	—		—	$	23,529
Year ended December 31, 2017	$	23,529	—	5,855	—		21,527	$	50,911

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* Amounts not charged to operations are charged to other comprehensive income or deferred tax assets (liabilities).

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

A reconciliation of the beginning and ending amounts of unrecognized income tax benefits for the years ended December 31, 2017, 2016 and 2015 is as follows (amounts in thousands):

	Years Ended December 31,
	2017			2016			2015
Balance at January 1	$	21,925		$	20,836		$	19,903
Tax positions related to current year:
Additions	1,083			1,225			1,186
Tax positions related to prior years:
Additions	16			256			—
Reductions	(372		)	(171		)	(35		)
Settlements	—			(221		)	(218		)
Balance at December 31	$	22,652		$	21,925		$	20,836