Cash, cash equivalents and restricted cash (Details Textual) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Cash and Cash Equivalents Including Restricted Cash	$ 4,717
Restricted cash	2,039	2,039
Cash and cash equivalents	2,678	3,443	3,342	3,704
Cash, FDIC Insured Amount	518
Cash, Uninsured Amount	17
Letter Of Credit [Member]
Other Restricted Assets, Noncurrent	39
Convertible Preferred Series A Stock Agreement [Member]
Other Restricted Assets, Noncurrent	$ 2,000