The components of loss before provision for income taxes were as follows (in thousands):

	Year Ended January 31,
	2020			2019			2018
United States	$	(104,362	)	$	(90,408	)	$	(107,701	)
Foreign		(38,576	)		(42,806	)		(46,544	)
Total	$	(142,938	)	$	(133,214	)	$	(154,245	)

The components of the provision for income taxes were as follows (in thousands):

	Year Ended January 31,
	2020			2019			2018
Current:
Federal	$	—		$	—		$	(430	)
State		196			162			75
Foreign		1,485			1,885			1,426
Total	$	1,681		$	2,047		$	1,071
Deferred:
Federal	$	—		$	—		$	(134	)
State		32			18			18
Foreign		(303	)		(667	)		(240	)
Total	$	(271	)	$	(649	)	$	(356	)
Provision for income taxes	$	1,410		$	1,398		$	715

As a result of the December 2017 enacted Tax Cuts and Jobs Act (Tax Act), the corporate tax rate changed from 34% to 21% effective January 1, 2018. For the fiscal year ended January 31, 2020, we are subject to the corporate tax rate of 21%. The items accounting for the difference between income taxes computed at the federal statutory income tax rate of 21% and the provision for income taxes consisted of the following (in thousands):

	Year Ended January 31,
	2020			2019			2018
Tax benefit at federal statutory rate	$	(30,017	)	$	(27,975	)	$	(50,772	)
State taxes, net of federal benefit		(3,122	)		(2,672	)		(7,803	)
Foreign rate difference		(305	)		1,798			7,988
Nondeductible expenses		2,313			535			689
Research and development credit		(6,670	)		(5,536	)		(3,967	)
Stock-based compensation		6,325			(6,541	)		(4,148	)
Change in reserve for unrecognized tax benefits		6,670			5,507			3,537
Other		(246	)		193			(383	)
Change in valuation allowance, including the effect of tax rate change		26,462			35,061			(34,119	)
Effect of tax rate change on deferred tax assets		—			1,028			89,693
Total provision for income taxes	$	1,410		$	1,398		$	715

The significant components of our deferred tax assets and liabilities were as follows (in thousands):

	January 31,
	2020			2019
Deferred tax assets:
Net operating loss carryover	$	253,561		$	233,952
Accruals and reserves		10,187			19,771
Stock-based compensation		15,930			16,239
Depreciation and amortization		6,288			6,751
Operating lease liabilities		62,698			—
Tax credit carryover		4,325			4,325
Deferred business interest expense		1,061			—
Other		1,904			557
Total deferred tax assets		355,954			281,595
Valuation allowance		(301,757	)		(275,293	)
Total deferred tax assets, net of valuation allowance		54,197			6,302
Deferred tax liabilities:
Operating lease right-of-use assets, net		(49,966	)		—
Deferred commissions		(2,433	)		(4,882	)
Goodwill with indefinite life amortization		(424	)		(283	)
Other		(28	)		(56	)
Total deferred tax liabilities		(52,851	)		(5,221	)
Net deferred tax assets	$	1,346		$	1,081

In assessing the realizability of deferred tax assets, we consider whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. As a result, we have established a full valuation allowance against our U.S. and United Kingdom net deferred tax assets to the extent they are not offset by liabilities from uncertain tax positions based on our history of losses. The valuation allowance increased by $26.5 million and $25.9 million, respectively, during the years ended January 31, 2020 and 2019.

As a result of the Tax Act, net operating loss carryforwards generated for tax years ending after December 31, 2018 will have an indefinite carryforward period. In light of the new law, we have assessed and believe that, it is more likely than not, that the net operating loss carryforwards generated for the fiscal year ended January 31, 2020 in the U.S. will be realized to the extent of future reversal of taxable temporary difference associated with indefinite-lived intangible assets.

In connection with the adoption of ASC 842 in fiscal year 2020, the Company recognized a deferred tax asset in the amount of $62.7 million related lease liabilities and a deferred tax liability in the amount of $50.0 million for the year ended January 31, 2020. The net effect of these adjustments to the deferred tax asset and liability will be offset with an adjustment to the valuation allowance.

As of January 31, 2020, we had federal, state and foreign net operating loss carryforwards of $735.7 million, $685.7 million and $320.6 million, respectively, available to offset future taxable income. The federal net operating loss carryforwards generated prior to fiscal year 2018 will expire at various dates beginning in 2025, if not utilized. We have federal net operating loss carryforwards of $216.7 million, which can be carried forward indefinitely. The state net operating loss carryforwards will expire at various dates beginning in 2022, if not utilized. The foreign net operating loss carryforwards do not expire. In addition, as of January 31, 2020, we had federal and state research and development tax credit carryforwards of $32.6 million and $33.8 million, respectively. The federal research and development tax credit carryforwards will expire beginning in 2025 if not utilized. The state research and development tax credit carryforwards do not expire.

Utilization of the federal and state net operating loss may be subject to substantial annual limitation due to the ownership change limitations provided by Section 382 of the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitation may result in the expiration of net operating losses and credits before utilization.

We evaluate tax positions for recognition using a more-likely-than-not recognition threshold, and those tax positions eligible for recognition are measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon the effective settlement with a taxing authority that has full knowledge of all relevant information. We believe that we have provided adequate reserves for our income tax uncertainties in all open tax years.

A reconciliation of the gross unrecognized tax benefits is as follows (in thousands):

	Year Ended January 31,
	2020			2019			2018
Unrecognized tax benefits—beginning of period	$	49,883		$	36,194		$	28,644
Reductions for tax positions related to prior year		(10	)		—			(971	)
Reductions to unrecognized tax benefits as a result of a lapse of the applicable statute of limitations		—			(20	)		(337	)
Additions for tax positions related to prior year		—			2,140			—
Additions for tax positions related to current year		13,687			11,569			8,858
Unrecognized tax benefits—end of period	$	63,560		$	49,883		$	36,194

The gross unrecognized tax benefits, if recognized, would not materially affect the effective tax rate as of January 31, 2020, 2019 and 2018. We do not expect our gross unrecognized tax benefits to change significantly over the next 12 months.

Our policy is to classify interest and penalties associated with uncertain tax positions, if any, as a component of our income tax provision. Interest and penalties were not significant during the years ended January 31, 2020, 2019 and 2018.

We file tax returns in the U.S. for federal, California, and other states. All tax years remain open to examination for both federal and state purposes as a result of our net operating loss and credit carryforwards. We began to file foreign tax returns in the United Kingdom starting with the year ended January 31, 2013, in France, Germany, and Japan starting with the year ended January 31, 2014, in Canada starting with the year ended January 31, 2015 and in Australia, Sweden, and Netherlands starting with the year ended January 31, 2016. Certain tax years remain open to examination.