Income taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Schedule Components of Loss Before Income Taxes

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

	Year ended December 31,
	2016			2015			2014
U.S.	$	(210,188	)	$	(162,287	)	$	(61,118	)
Foreign		(53,931	)		(4,436	)		612
Total	$	(264,119	)	$	(166,723	)	$	(60,506	)

Summary of (Benefit from) Provision for Income Taxes

The (benefit from) provision for income taxes were as follows (in thousands):

	Year ended December 31,
	2016			2015		2014
Current
Federal	$	—		$	—	$	—
State		—			—		1
Foreign		—			60		—
Deferred
Federal		(588	)		—		(9,390	)
State		(24	)		—		(2,408	)
Foreign		—			—		—
Total income tax expense (benefit)	$	(612	)	$	60	$	(11,797	)

Reconciliation of Income Tax (Benefit) Provision Computed at the Statutory Federal Income Tax Rate to Effective Income Tax Rate (Benefit) Provision as Reflected in the Financial Statements

A reconciliation of income tax (benefit) provision computed at the statutory federal income tax rate to the Company’s effective income tax rate (benefit) provision as reflected in the financial statements is as follows:

	Year ended December 31,
	2016			2015			2014
Federal income tax expense at statutory rate		34.0	%		34.0	%		34.0	%
State income tax, net of federal benefit		3.3	%		4.2	%		4.0	%
Permanent differences		(5.3	%)		(6.4	%)		(3.2	%)
Research and development credit		15.0	%		14.6	%		25.7	%
Foreign differential		(7.0	%)		(1.0	%)		0.0	%
Other		0.0	%		(0.5	%)		0.0	%
Change in valuation allowance		(39.9	%)		(44.9	%)		(41.0	%)
Effective income tax rate benefit		0.1	%		0.0	%		19.5	%

Components of Deferred Tax Assets and Liabilities

The significant components of the Company’s deferred tax assets and liabilities are comprised of the following (in thousands):

	Year ended December 31,
	2016			2015
Deferred tax assets:
U.S. net operating loss carryforwards	$	106,064		$	62,844
Foreign net operating loss carryforwards		—			194
Tax credit carryforwards		87,117			47,386
Capitalized research and development expenses, net		631			979
Capital lease		47,191			24,315
Deferred revenue		18,231			16,438
Capitalized license fees		11,752			5,488
Accruals and other		32,172			19,486
Total deferred tax assets		303,158			177,130
Intangible assets		(8,129	)		(9,606	)
Fixed assets		(48,902	)		(26,681	)
Less valuation allowance		(246,127	)		(140,843	)
Net deferred taxes	$	—		$	—