| 
           Condensed Consolidated Financial Statement Detail (Details) 
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        3 Months Ended | 9 Months Ended | 1 Months Ended | 1 Months Ended | 9 Months Ended | 1 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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           Sep. 30, 2013
 
          USD ($) 
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           Sep. 30, 2012 
         | 
        
           Sep. 30, 2013
 
          USD ($) 
         | 
        
           Sep. 30, 2012 
         | 
        
           Dec. 31, 2012
 
          USD ($) 
         | 
        
           Feb. 28, 2010
 
          Five year warrants issued in February 2010 [Member]
 
          USD ($) 
         | 
        
           Feb. 28, 2010
 
          Five year warrants issued in February 2010 [Member] 
         | 
        
           Mar. 31, 2012
 
          Five year warrants issued in March 2012 [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Five year warrants issued in March 2012 [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Five year warrants issued in March 2012 [Member] 
         | 
        
           Dec. 31, 2012
 
          Five year warrants issued in March 2012 [Member]
 
          USD ($) 
         | 
        
           Mar. 31, 2012
 
          Five year warrants issued in March 2012 [Member] 
         | 
        
           Jun. 30, 2009
 
          Warrants issued to private investors [Member]
 
          USD ($) 
         | 
        
           Jun. 30, 2009
 
          Warrants issued to private investors [Member] 
         | 
        
           Sep. 30, 2012
 
          Options Contract [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Options Contract [Member]
 
          USD ($)
 
          Contract 
         | 
        
           Sep. 30, 2012
 
          Options Contract [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Options Contract [Member]
 
          EUR (€) 
         | 
        
           Sep. 30, 2013
 
          Option Contract 1 [Member]
 
          EUR (€) 
         | 
        
           Sep. 30, 2013
 
          Option Contract 2 [Member]
 
          EUR (€) 
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           Sep. 30, 2013
 
          Demand Deposits [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2012
 
          Demand Deposits [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Money Market Funds [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2012
 
          Money Market Funds [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2013
 
          Common stock options and restricted stock units [Member] 
         | 
        
           Sep. 30, 2012
 
          Common stock options and restricted stock units [Member] 
         | 
        
           Sep. 30, 2013
 
          Common stock options and restricted stock units [Member] 
         | 
        
           Sep. 30, 2012
 
          Common stock options and restricted stock units [Member] 
         | 
        
           Sep. 30, 2013
 
          Warrants for common stock [Member] 
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           Sep. 30, 2012
 
          Warrants for common stock [Member] 
         | 
        
           Sep. 30, 2013
 
          Warrants for common stock [Member] 
         | 
        
           Sep. 30, 2012
 
          Warrants for common stock [Member] 
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      ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||||||||||||||||||||||||||||||||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 22,795,000 | 22,356,000 | 22,123,000 | 18,730,000 | 6,825,000 | 5,730,000 | 6,017,000 | 5,788,000 | 15,970,000 | 16,626,000 | 16,106,000 | 12,942,000 | |||||||||||||||||||||||
| Cash and Cash Equivalents [Line Items] | |||||||||||||||||||||||||||||||||||
| Cash equivalents | $ 16,200,000 | $ 7,800,000 | $ 57,800,000 | $ 37,500,000 | |||||||||||||||||||||||||||||||
| Short-term Investments [Abstract] | |||||||||||||||||||||||||||||||||||
| Short-term investments, U.S. treasury securities | 0 | 0 | 39,987,000 | [1] | |||||||||||||||||||||||||||||||
| Derivative [Line Items] | |||||||||||||||||||||||||||||||||||
| Notional amount of derivative liability | 15,000,000 | ||||||||||||||||||||||||||||||||||
| Number of foreign exchange option contracts | 2 | ||||||||||||||||||||||||||||||||||
| Derivative, amount of hedged item | 1,500,000 | 15,000,000 | |||||||||||||||||||||||||||||||||
| Derivative, premiums | 1,500,000 | ||||||||||||||||||||||||||||||||||
| Derivative fair value | 300,000 | ||||||||||||||||||||||||||||||||||
| Derivative, loss | 100,000 | 200,000 | 700,000 | ||||||||||||||||||||||||||||||||
| Accrued liabilities [Abstract] | |||||||||||||||||||||||||||||||||||
| Accrued payroll and other benefits | 3,112,000 | 3,112,000 | 3,978,000 | ||||||||||||||||||||||||||||||||
| Accrued management incentive compensation | 2,708,000 | 2,708,000 | 2,461,000 | ||||||||||||||||||||||||||||||||
| Accrued clinical trial costs | 500,000 | 500,000 | 4,702,000 | ||||||||||||||||||||||||||||||||
| Other | 1,696,000 | 1,696,000 | 1,904,000 | ||||||||||||||||||||||||||||||||
| Total | 8,016,000 | 8,016,000 | 13,045,000 | [1] | |||||||||||||||||||||||||||||||
| Class of Warrant or Right [Line Items] | |||||||||||||||||||||||||||||||||||
| Warrants outstanding (in shares) | 1,260,000 | 13,673,183 | 14,834,577 | 347,826 | |||||||||||||||||||||||||||||||
| Exercise price (in dollars per share) | $ 10.50 | $ 1.76 | $ 19.50 | ||||||||||||||||||||||||||||||||
| Fair value of warrant liability | 52,000 | 52,000 | 39,100,000 | 15,000,000 | |||||||||||||||||||||||||||||||
| Gain (loss) on revaluation of warrant liability | 25,700,000 | ||||||||||||||||||||||||||||||||||
| Warrant Term | 5 years | 5 years | 5 years | ||||||||||||||||||||||||||||||||
| Reclassification of warrant liability to equity | $ 1,600,000 | ||||||||||||||||||||||||||||||||||
          
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