Note 12 — Income Taxes

Loss before provision (benefit) for income taxes includes the following components (in thousands):

	Year Ended December 31,
	2016			2015			2014
Domestic	$	(155,375	)	$	(81,931	)	$	(56,414	)
Foreign		2,727			1,260			1,986
Loss before provision (benefit) for income taxes	$	(152,648	)	$	(80,671	)	$	(54,428	)

Provision for Income Taxes

The provision (benefit) for income taxes consists of the following (in thousands):

	Year Ended December 31,
	2016			2015			2014
Current:
Federal	$	—		$	—		$	—
State		(1	)		(1	)		1
Foreign		992			529			(482	)
Total Current		991			528			(481	)
Deferred:
Federal		—			—			—
State		—			—			—
Foreign		(115	)		(22	)		(31	)
Total Deferred		(115	)		(22	)		(31	)
Provision (benefit) for income taxes	$	876		$	506		$	(512	)

The foreign benefit provision in the year ended December 31, 2014 is due to the reduction in taxes related to a favorable determination received from India proceedings.

Income tax provision related to continuing operations differs from the amount computed by applying the statutory income tax rate of 35% to pretax loss as follows (in thousands):

	Year Ended December 31,
	2016			2015			2014
U.S. federal provision (benefit)
At statutory rate	$	(53,427	)	$	(28,235	)	$	(19,050	)
Change in valuation allowance		51,981			22,210			11,831
Non-cash interest expense on liability related to sale of future royalties		6,899			7,217			7,311
Stock-based compensation		528			674			2,832
Foreign tax deduction		—			1,773			—
Research credits		(4,543	)		(4,529	)		(2,933	)
Other		(562	)		1,396			(503	)
Provision (benefit) for income taxes	$	876		$	506		$	(512	)

Deferred Tax Assets and Liabilities

Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	508,406		$	447,761
Research and other credits		74,917			70,258
Stock-based compensation		26,357			22,832
Deferred revenue		23,035			29,658
Reserves and accruals		12,269			8,309
Capitalized research expenses		11,587			12,440
Property, plant and equipment		6,882			6,451
Sale of future royalties		1,611			12,319
Other		750			3,158
Deferred tax assets before valuation allowance		665,814			613,186
Valuation allowance for deferred tax assets		(665,514	)		(612,996	)
Total deferred tax assets		300			190
Total deferred tax liabilities		—			—
Net deferred tax assets	$	300		$	190

Realization of our deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Because of our lack of U.S. earnings history, the net U.S. deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $52.5 million and $17.3 million during the years ended December 31, 2016 and 2015, respectively. The valuation allowance includes approximately $35.6 million of income tax benefit at both December 31, 2016 and December 31, 2015 related to stock-based compensation and exercises prior to the implementation of the accounting guidance for stock-based compensation that will be credited to additional paid in capital when realized.

Undistributed earnings of our foreign subsidiary in India are considered to be permanently reinvested and accordingly, no deferred U.S. income taxes have been provided thereon. Upon distribution of those earnings in the form of dividends or otherwise, we would be subject to U.S. income tax. As of December 31, 2016, U.S. income taxes have not been provided on a cumulative total of $3.4 million of such earnings. Any incremental tax liability would be insignificant due to foreign tax credits that would be realized upon distribution.

Net Operating Loss and Tax Credit Carryforwards

As of December 31, 2016, we had a net operating loss carryforward for federal income tax purposes of approximately $1,413.3 million, portions of which will begin to expire in 2018. As of December 31, 2016, we had a total state net operating loss carryforward of approximately $473.6 million, portions of which will begin to expire in 2017. Utilization of some of the federal and state net operating loss and credit carryforwards are subject to annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986 and similar state provisions.

We have federal research credits of approximately $50.1 million, which will begin to expire in 2019 and state research credits of approximately $25.2 million which have no expiration date. We have federal orphan drug credits of $17.7 million which will begin to expire in 2026. These tax credits are subject to the same limitations discussed above.

Unrecognized tax benefits

We have incurred net operating losses since inception. Our policy is to include interest and penalties related to unrecognized tax benefits, if any, within the provision for income taxes in the consolidated statements of operations. If we are eventually able to recognize our uncertain positions, our effective tax rate may be reduced. We currently have a full valuation allowance against our U.S. net deferred tax asset which would impact the timing of the effective tax rate benefit should any of these uncertain tax positions be favorably settled in the future. Any adjustments to our uncertain tax positions would result in an adjustment of our net operating loss or tax credit carry forwards rather than resulting in a cash outlay. The decrease in the unrecognized tax benefits in 2015 primarily relates to a California Supreme Court decision relating to the calculation of apportionment of income.

We file income tax returns in the U.S., California, Alabama, and India. Because of net operating losses and research credit carryovers, substantially all of our domestic tax years remain open and subject to examination. We are currently under examination in India for the fiscal years ending 2009, 2013 and 2014.

We have the following activity relating to unrecognized tax benefits (in thousands):

	December 31,
	2016		2015			2014
Beginning balance	$	17,384	$	27,522		$	16,363
Tax positions related to current year
Additions:
Federal		530		529			502
State		499		443			6,141
Reductions		—		—			—
Tax positions related to prior year
Additions:
Federal		—		—			—
State		—		—			5,258
Foreign		—		—			—
Reductions		—		(11,110	)		(742	)
Settlements		—		—			—
Lapses in statute of limitations		—		—			—
Ending balance	$	18,413	$	17,384		$	27,522

Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next twelve months, we do not anticipate any significant changes to unrecognized tax benefits over the next twelve months. During the years ended December 31, 2016, 2015 and 2014, no significant interest or penalties were recognized relating to unrecognized tax benefits.