Income taxes (Tables)

12 Months Ended

Dec. 31, 2015

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,
	2015			2014			2013
U.S.	$	(162,287	)	$	(61,118	)	$	(26,018	)
Foreign		(4,436	)		612			697
Total	$	(166,723	)	$	(60,506	)	$	(25,321	)

Components of Benefit for Income Taxes

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

	Year ended December 31,
	2015		2014			2013
Current
Federal	$	—	$	—		$	—
State		—		1			—
Foreign		60		—			—
Deferred
Federal		—		(9,390	)		—
State		—		(2,408	)		—
Foreign		—		—			—
Total income tax expense (benefit)	$	60	$	(11,797	)	$	—

Reconciliation of Income Tax Expense Computed at the Statutory Federal Income Tax Rate to Effective Income Tax Rate as Reflected in the Financial Statements

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

	Year ended December 31,
	2015			2014			2013
Federal income tax expense at statutory rate		34.0	%		34.0	%		34.0	%
State income tax, net of federal benefit		4.2	%		4.0	%		4.5	%
Permanent differences		(6.4	%)		(3.2	%)		(0.6	%)
Research and development credit		14.6	%		25.7	%		6.0	%
Other		(1.5	%)		0.0	%		0.0	%
Change in valuation allowance		(44.9	%)		(41.0	%)		(43.9	%)
Effective income tax rate benefit		0.0	%		19.5	%		0.0	%

Net Deferred Tax Assets

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

	Year ended December 31,
	2015			2014
Deferred tax assets:
U.S. net operating loss carryforwards	$	62,844		$	33,767
Foreign net operating loss carryforwards		194			899
Tax credit carryforwards		47,386			23,274
Capitalized research and development expenses, net		979			1,372
Capital lease		24,315			—
Deferred revenue		16,438			12,050
Capitalized license fees		5,488			384
Accruals and other		19,486			7,168
Total deferred tax assets		177,130			78,914
Intangible assets		(9,606	)		(11,084	)
Fixed assets		(26,681	)		(2,526	)
Less valuation allowance		(140,843	)		(65,304	)
Net deferred taxes	$	—		$	—