Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v2.4.0.8
Fair Value Measurements (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2014
Warrant Liabilities [Member]
Sep. 30, 2013
Warrant Liabilities [Member]
Sep. 30, 2014
Warrant Liabilities [Member]
Sep. 30, 2013
Warrant Liabilities [Member]
Sep. 30, 2014
Warrant Liabilities [Member]
Minimum [Member]
Dec. 31, 2013
Warrant Liabilities [Member]
Minimum [Member]
Sep. 30, 2014
Warrant Liabilities [Member]
Maximum [Member]
Dec. 31, 2013
Warrant Liabilities [Member]
Maximum [Member]
Sep. 30, 2014
Recurring [Member]
Dec. 31, 2013
Recurring [Member]
Sep. 30, 2014
Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Dec. 31, 2013
Recurring [Member]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Sep. 30, 2014
Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Dec. 31, 2013
Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
Sep. 30, 2014
Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Dec. 31, 2013
Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
Assets:                                
Money market funds                 $ 34,566 [1] $ 82,759 [1] $ 34,566 [1] $ 82,759 [1] $ 0 [1] $ 0 [1] $ 0 [1] $ 0 [1]
U.S. treasury securities                 5,000 19,990 5,000 19,990 0 0 0 0
Foreign exchange options                 35 361 0 0 35 361 0 0
Total                 39,601 103,110 39,566 102,749 35 361 0 0
Liabilities:                                
Contingent warrant liabilities                 33,658 69,869 0 0 0 0 33,658 69,869
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]                                
Expected volatility (in hundredths)         43.00% 66.10% 68.70% 86.60%                
Risk-free interest rate (in hundredths)         0.00% 0.10% 0.60% 0.80%                
Expected term         0 years 2 months 12 days 0 years 10 months 24 days 2 years 4 months 24 days 3 years 2 months 12 days                
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]                                
Balance, beginning of period     69,869                          
Reclassification of contingent warrant liability to equity upon exercise of warrants     (2,526)                          
Net increase in fair value of contingent warrant liabilities upon revaluation (5,700) 11,100 (33,685) 25,700                        
Balance, end of period $ 33,658   $ 33,658                          
[1] Included in cash and cash equivalents