Income taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income taxes

Schedule of reconciliation of the expected income tax (benefit) computed using the federal statutory income tax rate to the effective income tax rate

A  reconciliation of the U.S. federal statutory tax rate to the Company’s effective tax rate is as follows:

							Period from
							June 19, 2013
							(Inception) to
	Year ended December 31,						December 31,
	2015			2014			2013
Income tax computed at federal statutory tax rate		34.0	%		34.0	%		34.0	%
State taxes, net of federal benefit		4.0	%		5.5	%		6.3	%
General business credit carryovers		3.2	%		2.2	%		2.4	%
Non-deductible expenses		(15.6)	%		(5.0)	%		(0.7)	%
Change in valuation allowance		(25.6)	%		(36.7)	%		(42.0)	%
		—	%		—	%		—	%

Schedule of principal components of the Company’s deferred tax assets and liabilities

The significant components of the Company’s deferredtax assets and liabilities as of December 31, 2015 and 2014 are as follows:

	Year ended December 31,
	2015		2014
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	12,521	$	6,643
Tax credit carryforwards		1,969		673
Deferred rent		516		626
Non-deductible expenses		577		79
Intangibles		376		327
Stock compensation		115		—
Total deferred tax assets		16,074		8,348
Less valuation allowance		(15,207)		(7,599)
Net deferred tax assets		867		749
Deferred tax liabilities—depreciation and amortization		(867)		(749)
Net deferred taxes	$	—	$	—