Income taxes (Tables)

12 Months Ended

Dec. 31, 2012

Income taxes

Schedule of reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations

	Year Ended December 31, 2012			Period from April 5, 2011 (inception) to December 31, 2011
Income tax benefit using U.S. federal statutory rate		34.00	%		34.00	%
State income taxes, net of federal benefit		5.42	%		5.47	%
Research and development tax credits		0.00	%		1.70	%
Permanent items		(2.78	)%		(3.93	)%
Change in the valuation allowance		(36.64	)%		(37.24	)%
		—	%		—	%

Schedule of principal components of the Company's deferred tax assets

The principal components of the Company's deferred tax assets are as follows (in thousands):

	December 31, 2012			December 31, 2011
Deferred tax assets:
Net operating loss carryforwards	$	5,527		$	750
Research and development credits		153			67
Stock-based compensation		142			22
Other		106			138
Gross deferred tax assets		5,928			977
Valuation allowance		(5,928	)		(977	)
Net deferred tax asset	$	—		$	—