Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details Textual)

v2.4.0.6
Fair Value Measurements (Details Textual) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Fair Value Measurements (Textual) [Abstract]    
Maximum maturity period of collateralized securities 1 year  
Maximum maturity period of cash and cash equivalents 90 days  
Maximum maturity period of short-term investments 1 year  
Maximum maturity period of marketable securities 1 year 1 year
Other than temporary impairments to investment in marketable securities $ 0  
Warrant liability $ 3,422,000 $ 7,881,000