Convertible note and warrants (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Proceeds from issuance of convertible notes payable	$ 3,500	$ 0	$ 3,500	$ 0
Fair value of warrants recorded as corresponding debt discount	500	0	400	0
Beneficial conversion feature on convertible note	500	0	500	0
Amortization of debt discount	43	0	43	0
Interest expense	23	0	23	0
Amortization of deferred financing costs	$ 33	$ 0	$ 33	$ 0