Restatement of previously issued financial statements (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Net loss	$ (4,725)	$ (7,555)
Warrant expense	141	0
Fair value of warrant liability	(557)	0
Accrued expenses	(230)	(421)
Net cash used in operating activities	(3,467)	(7,635)
Proceeds from issuance of preferred stock, net	4,500	0
Net cash provided by financing activities	3,439	639
Scenario, Previously Reported [Member]
Net loss	(4,982)
Warrant expense	8
Fair value of warrant liability	0
Accrued expenses	(306)
Net cash used in operating activities	(3,379)
Proceeds from issuance of preferred stock, net	4,412
Net cash provided by financing activities	$ 3,351