Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Pretax earnings (loss) were generated by both domestic and foreign operations as follows (in thousands):

A reconciliation of the expected statutory federal income tax provision to the actual income tax provision is summarized as follows (in thousands):

	Years Ended December 31,
	2015			2014			2013
Expected income taxes benefit at federal statutory rate	$	(16,311	)	$	(8,279	)	$	(6,804	)
State income taxes, net of federal benefit		—			(2,023	)		(634	)
Permanent items and other		19			(321	)		2
Stock-based compensation		734			396			—
Research credits		(2,674	)		(372	)		(397	)
Unrecognized tax benefits		1,070			144			159
Foreign rate differential		84			(3,391	)		2,978
Change in tax rate		3,551			—			—
Other, net		112			293			(26	)
Change in valuation allowance		13,415			13,553			4,722
Income tax (benefit) expense	$	—		$	—		$	—

Significant components of our deferred tax assets are summarized as follows (in thousands):

	December 31,
	2015			2014			2013
Net operating loss carryforwards	$	24,869		$	20,066		$	13,093
Capitalized research and development expenses		14,181			7,855			6,684
Research credits and other state credits		3,565			1,368			1,171
Intangible assets		4,176			4,926			28
Depreciation and amortization		(120	)		(260	)		(360	)
Reserve and accruals		1,648			891			677
Valuation allowance		(48,319	)		(34,846	)		(21,293	)
Net deferred tax assets	$	—		$	—		$	—

The activity related to our unrecognized tax benefits is summarized as follows (in thousands):

Balance as of December 31, 2012	$	774
Increase related to prior year tax positions		79
Increase related to current year tax positions		94
Balance as of December 31, 2013		947
Increase related to prior year tax positions		—
Increase related to current year tax positions		177
Other decreases		(18	)
Balance as of December 31, 2014		1,106
Increase related to prior year tax positions		2,404
Increase related to current year tax positions		1,523
Balance as of December 31, 2015		5,033