Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details)

v2.4.0.6
Fair Value Measurements (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Warrant Liabilities [Member]
    
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]    
Expected volatility (in hundredths) 40.00%  
Risk-free interest rate (in hundredths)   0.40%
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Balance, beginning of period $ 379 $ 4,245
Initial fair value of warrants issued in March 2012 6,390  
Reclassification of contingent warrant liability to equity upon exercise of warrants (940)  
Net decrease (increase) in fair value of contingent warrant liabilities upon revaluation 9,172 (3,866)
Balance, end of period 15,001 379
Warrant Liabilities [Member] | Minimum [Member]
    
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]    
Expected volatility (in hundredths)   102.10%
Risk-free interest rate (in hundredths) 0.30%  
Expected term 1 year 10 months 24 days 2 years 10 months 24 days
Warrant Liabilities [Member] | Maximum [Member]
    
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]    
Expected volatility (in hundredths)   103.20%
Risk-free interest rate (in hundredths) 0.70%  
Expected term 4 years 2 months 12 days 3 years 1 month 6 days
Recurring [Member]
    
Assets:    
Money market funds 37,461 [1] 27,222 [1]
U.S. treasury securities 39,987  
Foreign exchange options 488 1,202
Total 77,936 28,424
Liabilities:    
Contingent warrant liabilities 15,001 379
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
    
Assets:    
Money market funds 37,461 [1] 27,222 [1]
U.S. treasury securities 39,987  
Foreign exchange options 0 0
Total 77,448 27,222
Liabilities:    
Contingent warrant liabilities 0 0
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
    
Assets:    
Money market funds 0 [1] 0 [1]
U.S. treasury securities 0  
Foreign exchange options 488 1,202
Total 488 1,202
Liabilities:    
Contingent warrant liabilities 0 0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
    
Assets:    
Money market funds 0 [1] 0 [1]
U.S. treasury securities 0  
Foreign exchange options 0 0
Total 0 0
Liabilities:    
Contingent warrant liabilities $ 15,001 $ 379
[1] Included in cash and cash equivalents