We recorded an income tax benefit of $1.4 million, a provision of less than $0.1 million and a benefit of less than $0.1 million for the years ended December 31, 2019, 2018 and 2017, respectively. The income tax provision for the year ended December 31, 2019 was primarily due to the state and foreign income tax expense and tax benefit related to a partial release of the valuation allowance in connection with the myStrength acquisition. The income tax provision and benefit for the years ended December 31, 2018 and 2017, respectively, was primarily due to state and foreign income tax expense and federal benefit related to release of a valuation allowance as a result of our acquisitions.



	Year Ended December 31,
	2019			2018		2017
	(in thousands)
Current:
U.S. Federal	$	—		$	—	$	—
State	20			7		2
Foreign	7			21		6
Total current	$	27		$	28	$	8
Deferred:
U.S. Federal	$	(1,064	)	$	—	$	(61	)
State	(332		)	—		(8		)
Foreign	—			—		—
Total deferred	$	(1,396	)	$	—	$	(69	)
Total provision for (benefit from) income taxes	$	(1,369	)	$	28	$	(61	)



	Year Ended December 31,
	2019		2018		2017
Expected income tax benefit at the federal statutory rate	21.00	%	21.00	%	34.00	%
State taxes, net of federal benefit	(0.06	)	(0.01	)	0.04
Foreign losses taxed at different rates	(0.01	)	(0.11	)	—
Research and development credit, net	4.39		2.79		3.56
Tax Cuts and Jobs Act revaluation	—		—		(57.00	)
Non-deductible items	(0.97	)	(0.53	)	(1.15	)
Stock-based compensation	12.00		2.59		1.90
Other	0.03		0.76		(0.85	)
Release of valuation allowance due to acquisition	2.47		—		—
Change in valuation allowance	(36.43	)	(26.57	)	19.86
Total	2.42	%	(0.08	)%	0.36	%

Deferred tax assets are recognized for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. Management assesses whether it is more likely than not that some portion or all of the deferred tax assets will be realized. Deferred tax assets are reduced by a valuation allowance to the extent management believes it is not more likely than not to be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income. Management makes estimates and judgments about future taxable income based on assumptions that are consistent with our plans and estimates.



	Year Ended December 31,
	2019			2018			2017
	(in thousands)
Deferred tax assets:
Federal and state net operating loss carryforwards	$	45,193		$	31,508		$	15,307
Research and development tax credits	7,771			3,794			2,127
Stock-based compensation	8,434			2,055			585
Accruals and reserves	1,270			1,009			405
Deferred revenue	4,127			2,487			1,286
Other	573			230			71
Gross deferred tax assets	67,368			41,083			19,781
Valuation allowance	(59,267		)	(38,310		)	(19,302		)
Net deferred tax assets	$	8,101		$	2,773		$	479
Deferred tax liabilities:
Property and equipment	(2,450		)	(1,313		)	(436		)
Acquired intangible assets	(4,119		)	(1,460		)	(43		)
Prepaid insurance and deferred commissions	(1,532		)	—			—
Net deferred tax liabilities	$	(8,101	)	$	(2,773	)	$	(479	)
Net deferred tax assets	$	—		$	—		$	—

Due to the uncertainties surrounding the realization of deferred tax assets through future taxable income, we have provided a full valuation allowance, and therefore no benefit has been recognized for the net operating loss carryforwards and other deferred tax assets. The valuation allowance increased by $21.0 million and $19.0 million during the years ended December 31, 2019 and 2018, respectively. We maintain a full valuation allowance against the net federal and state deferred tax assets as it is not more likely than not that the assets will be realized based on our history of losses.



	Year Ended December 31,
	2019		2018		2017
	(in thousands)
Net operating losses, federal	$	189,284	$	122,824	$	66,906
Net operating losses, California	9,512		6,251		3,144
Net operating losses, other states	80,808		57,494		11,396
Tax credits, federal	6,630		3,312		2,070
Tax credits, state	4,258		2,273		1,292
Total	$	290,492	$	192,154	$	84,808

As of December 31, 2019, we had $189.3 million of federal and $90.3 million of state net operating loss carryforwards available to offset future taxable income. Carryforwards generated in tax years ended December 31, 2017 and prior will expire in varying amounts beginning in 2024. Carryforwards generated in the tax year ended December 31, 2018 and future years do not expire for federal purposes.

As of December 31, 2019, we had $6.6 million of federal research credits and $4.3 million of state research credits available to offset future tax liabilities. The federal credit carryforwards expire beginning in 2034. The state credits do not expire. Federal and California tax laws impose limitations on the utilization of NOL and credit carryforwards in the event of an "ownership change" for tax purposes, as defined in Section 382 of the Code. Accordingly, our ability to utilize these carryforwards may be limited as a result of such "ownership change."

We have no present intention of remitting undistributed earnings of foreign subsidiaries and, accordingly, no deferred tax liability has been established related to these earnings. Determination of the amount of an unrecognized deferred tax liability on these undistributed earnings is not practicable.

We are required to inventory, evaluate, and measure all uncertain tax positions taken or to be taken on tax returns and to record liabilities for the amount of such positions that may not be sustained, or may only partially be sustained, upon examination by the relevant taxing authorities. As of December 31, 2019, our total gross unrecognized tax benefits were $3.1 million exclusive of interest and penalties described below. As of December 31, 2018, our total gross unrecognized tax benefits were $1.8 million exclusive of interest and penalties described below. Because of our valuation allowance position, none of unrecognized tax benefits, if recognized, would reduce the effective tax rate in a future period. We do not expect that the total amounts of unrecognized tax benefits will significantly increase or decrease within twelve months of the reporting date.



	Year Ended December 31,
	2019		2018		2017
	(in thousands)
Unrecognized benefit—beginning of year	$	1,791	$	1,235	$	—
Gross increases—current year tax positions	1,326		556		337
Gross increases—prior year tax positions	—		—		898
Decreases—prior year tax positions	—		—		—
Unrecognized benefit—end of year	$	3,117	$	1,791	$	1,235

As of December 31, 2019 and 2018, we recorded no liability related to uncertain tax positions on the financial statements due to the fact that, if realized, all positions would result in additional utilization of deferred carryover attributes. Our policy is to include interest and penalties related to unrecognized tax benefits as a component of other income, net. The actual amount of any taxes due could vary significantly depending on the ultimate timing and nature of any settlement. We do not believe it is reasonably possible that a significant change in unrecognized tax benefits will occur in the next twelve months.

We file federal, state, and foreign income tax returns in the U.S. and abroad. For U.S. federal and state income tax purposes, the statute of limitations currently remains open for all years due to our NOL carryforwards. We are not currently under examination in any jurisdiction.

On December 22, 2017, the Tax Cuts and Jobs Act (“TCJA”) was signed into law making significant changes to the Code. Changes include, but are not limited to, a U.S. corporate income tax rate (“U.S. federal tax rate”) decrease to 21% effective January 1, 2018. As a result of the decrease in the U.S. federal tax rate to 21% effective January 1, 2018, we remeasured our deferred tax assets and liabilities using the U.S. federal tax rate that will apply when the related temporary differences are expected to reverse. Accordingly, this change in tax rate resulted in a reduction in our U.S. deferred tax assets by $9.7 million in 2017, which was fully offset by a corresponding reduction in our valuation allowance.

Other provisions of the TCJA include one-time transition tax on the mandatory deemed repatriation of cumulative foreign earnings. The one-time repatriation tax is based on the post-1986 earnings and profits that were previously deferred from U.S. income taxes. Due to our minimal foreign earnings and net operating loss carryforwards, the one-time repatriation tax did not result in additional income tax expense.