Loss from operations before income taxes is categorized geographically as follows:

	Year Ended December 31,
(in thousands)	2019			2018			2017
United States	$	(81,653	)	$	(152,045	)	$	(40,775	)
Foreign		5,015			(2,547	)		718
Total loss from operations before income taxes	$	(76,638	)	$	(154,592	)	$	(40,057	)

	Year Ended December 31,
(in thousands)	2019			2018			2017
Current income tax expense:
Federal	$	14		$	(70	)	$	(12	)
State		10			48			23
Foreign		873			677			790
Total current income tax expense		897			655			801
Deferred income tax expense:
Federal		(1,087	)		(483	)		(16,141	)
State		121			562			(248	)
Foreign		(2,710	)		(586	)		(459	)
Total deferred income tax benefit		(3,676	)		(507	)		(16,848	)
Total provision for (benefit from) income taxes	$	(2,779	)	$	148		$	(16,047	)

A reconciliation of the Company’s effective tax rate to the federal statutory rate is as follows:

	Year Ended December 31,
(in thousands)	2019			2018			2017
Tax at federal statutory rate	$	(16,094	)	$	(32,464	)	$	(14,020	)
State income tax, net of federal tax benefit		(4,102	)		(6,764	)		(3,898	)
Foreign tax rate differential		(2,651	)		626			(493	)
Stock-based compensation		1,885			2,378			2,645
Transition tax		—			—			2,261
Revaluation of deferred tax assets and liabilities		—			—			(10,259	)
Research and development credits		(2,033	)		(5,247	)		(4,028	)
Other		805			(106	)		659
Change in valuation allowance		19,411			41,725			11,086
Total provision for (benefit from) income taxes	$	(2,779	)	$	148		$	(16,047	)

As of December 31, 2019 and 2018, the tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities are as follows:

(in thousands)	December 31, 2019			December 31, 2018
Deferred tax assets:
Net operating losses	$	66,170		$	41,419
Tax credits		26,254			23,359
Stock-based compensation		22,299			25,208
Accrued compensation and related expenses		3,513			4,061
Financing obligation- leased facility		—			29,842
Lease liabilities		31,355			—
Intangible assets		72,226			—
Other		2,003			463
Total deferred tax assets:		223,820			124,352
Valuation allowance		(174,921	)		(81,127	)
Total deferred tax assets, net of valuation allowance:		48,899			43,225
Deferred tax liabilities:
Depreciation and amortization		(8,708	)		(26,844	)
Goodwill		(23,047	)		(19,307	)
Right-of-use assets		(19,077	)		—
Total deferred tax liabilities:		(50,832	)		(46,151	)
Total net deferred tax liabilities:	$	(1,933	)	$	(2,926	)

As of December 31, 2019, the Company had federal and state net operating losses of $238.7 million and $167.6 million, respectively. Unutilized federal and state net operating loss carryforwards will begin to expire in 2020.

As of December 31, 2019, the Company had federal research and development credits of $16.6 million which will begin to expire in 2032; state research and development credits of $13.4 million which will carryforward indefinitely; and foreign research and development credits of $1.1 million which will begin to expire in 2037.

Assessing the realizability of the Company’s deferred tax assets is dependent upon several factors, including the likelihood and amount, if any, of future taxable income in relevant jurisdictions during the periods in which those temporary differences become deductible. The Company has evaluated the criteria for realization of deferred tax

assets and, as a result, has determined that certain deferred tax assets are not realizable on a more likely than not basis. Accordingly, the Company recorded a valuation allowance of $174.9 million as of December 31, 2019. The valuation allowance increased by $93.7 million and increased by $46.5 million during the years ended December 31, 2019 and 2018, respectively.

Internal Revenue Code Section 382 and similar state provisions limit the use of net operating losses and tax credit carryforwards in certain situations where changes occur in the stock ownership of a company. In the event the Company has a change of ownership, utilization of net operating losses and tax credit carryforwards may be limited. Certain acquired net operating losses and tax credits are subject to limitations. Net operating losses and tax credits have been reduced to reflect the amounts that can be utilized to reduce taxes payable in the future.

No additional income taxes have been provided for any remaining undistributed foreign earnings not subject to the one-time, mandatory transition tax, or additional outside basis difference of $7.4 million, as these amounts continue to be indefinitely reinvested in foreign operations.

The Company recorded cumulative unrecognized tax benefits pursuant to ASC 740-10 in the amount of $4.9 million, $3.4 million and $1.5 million during the years ended December 31, 2019, 2018 and 2017, respectively.

The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits within the provision for income taxes. Amounts accrued for interest and penalties were not significant as of December 31, 2019 and 2018, respectively or during years ended December 31, 2019, 2018 and 2017, respectively. The Company believes that it has provided adequate reserves for its income tax uncertainties in all open tax years. As the outcome of the audits cannot be predicted with certainty, if any issues addressed in the Company's tax audits are resolved in a manner inconsistent with management's expectations, the Company could be required to adjust its provision for income taxes in the period such resolution occurs.

On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion invalidating the regulations relating to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision was issued by the Tax Court in December 2015. The IRS appealed the Tax Court decision in June 2016. On July 24, 2018, the Ninth Circuit Federal Court issued a decision that was subsequently withdrawn and a reconstituted panel conferred on the appeal. On June 7, 2019, the Ninth Circuit Federal Court panel upheld the cost-sharing regulations. On July 22, 2019, Intel Corporation, who acquired Altera Corp., filed a request for rehearing of the case by the entire Ninth Circuit Federal Court which was denied on November 11, 2019 and finally on February 10, 2020, Intel Corporation filed a petition with the United States Supreme Court. Due to the continuing uncertainty surrounding the status of the cost-sharing regulations, questions related to the scope of potential benefits or obligations, and the prospect of a Supreme Court ruling, the Company has not recorded any benefit or expense as of December 31, 2019. The Company continues to monitor ongoing developments and potential impacts to its consolidated financial statements.

Changes in balances during 2019 and 2018 and ending balances as of December 31, 2019 and 2018 in gross unrecognized tax benefits were as follows:

(in thousands)	December 31, 2019		December 31, 2018
Beginning balances	$	3,351	$	1,486
Increases related to tax positions taken during a prior year		156		584
Increases related to tax positions taken during the current year		1,398		1,351
Decreases related to tax positions taken during a prior year		—		(70	)
Decreases related to tax settlements with taxing authorities		—		—
Ending balances	$	4,905	$	3,351

The Company does not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease within the next 12 months. None of the unrecognized tax benefits, if recognized, would affect the effective tax rate.

The Company files income tax returns in the U.S. federal, state, and certain foreign jurisdictions. The Company’s U.S federal income tax return years 2015 through 2019 remain open to examination. The Company’s respective state and foreign income tax return years 2012 to 2019 remain open to examination. There are no income tax audits currently in progress.