Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Schedule of Geographical Breakdown of Loss Before Provision for Income Taxes

The geographical breakdown of loss before provision for income taxes is as follows:

	Year Ended December 31,
	2016			2015			2014
	(in thousands)
United States	$	(48,244	)	$	(53,376	)	$	(23,872	)
International		520			171			1
Loss before provision for income taxes	$	(47,724	)	$	(53,205	)	$	(23,871	)

Components of Provision for Income Taxes

The components of the provision for income taxes are as follows:

	Year Ended December 31,
	2016			2015			2014
	(in thousands)
Current tax provision:
Federal	$	—		$	—		$	—
State		—			—			—
Foreign		170			59			4
Total current tax provision		170			59			4
Deferred tax provision (benefit):
Foreign		(27	)		(4	)		(2	)
Total deferred tax provision (benefit)	$	(27	)	$	(4	)	$	(2	)
Total provision for income taxes	$	143		$	55		$	2

Reconciliation Between Income Taxes Computed at the Federal Statutory Income Tax Rate and the Provision for Income Taxes

The reconciliation between income taxes computed at the federal statutory income tax rate and the provision for income taxes is as follows:

	Year Ended December 31,
	2016			2015			2014
	(in thousands)
Federal statutory rate		34.0	%		34.0	%		34.0	%
Effect of:
Change in valuation allowance		(33.5	)		(27.8	)		(37.3	)
Federal tax credit		1.6			2.6			1.8
State income tax benefit, net of federal benefit		0.1			2.9			4.0
Conversion costs		—			—			—
Change in fair value of preferred stock warrants		—			(11.1	)		(2.0	)
Other permanent items		(2.5	)		(0.7	)		(0.5	)
Total provision for income taxes		(0.3	)%		(0.1	)%		—	%

Components of the Deferred Tax Assets

The components of the deferred tax assets are as follows:

	December 31,
	2016			2015
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	35,244		$	21,482
Research and development credits		2,597			1,923
License fee		3,339			3,413
Stock Based Compensation		2,291			1,042
Other		1,017			607
Gross deferred tax assets		44,488			28,467
Valuation allowance		(44,440	)		(28,448	)
Total deferred tax assets		48			19
Deferred tax liabilities:
Other		12			10
Total deferred tax liabilities		12			10
Total net deferred tax assets	$	36		$	9

Unrecognized Tax Benefits

The activity related to the gross amount of unrecognized tax benefits is as follows:

	Year Ended December 31,
	2016		2015			2014
	(in thousands)
Beginning balance	$	232	$	162		$	58
Increases based on tax positions related to prior years		—		—			—
Decreases based on tax positions related to prior years		—		(77	)		—
Increases based on tax positions in current year		79		147			104
Settlement		—		—			—
Lapse of statute of limitations		—		—			—
Ending balance	$	311	$	232		$	162