Cash, cash equivalents and restricted cash (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Oct. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Cash and Cash Equivalents [Line Items]
Cash and Cash Equivalents Including Restricted Cash	$ 7,137
Cash and cash equivalents	6,348	3,443		5,646	3,704
Cash, FDIC Insured Amount	700
Restricted Cash and Cash Equivalent Item, Description	Restricted cash includes $750 held in escrow relating to the sale of the Companys portfolio of medical imaging patents.
Cash Maintenance Provision Limit On Shares			345,012
Amount Released Out Of Restricted Cash	2,000
Letter Of Credit [Member]
Cash and Cash Equivalents [Line Items]
Other Restricted Assets, Noncurrent	$ 39