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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 | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 30, 2014
Warrant Liabilities [Member]
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Sep. 30, 2013
Warrant Liabilities [Member]
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Sep. 30, 2014
Warrant Liabilities [Member]
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Sep. 30, 2013
Warrant Liabilities [Member]
|
Sep. 30, 2014
Warrant Liabilities [Member]
Minimum [Member]
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Dec. 31, 2013
Warrant Liabilities [Member]
Minimum [Member]
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Sep. 30, 2014
Warrant Liabilities [Member]
Maximum [Member]
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Dec. 31, 2013
Warrant Liabilities [Member]
Maximum [Member]
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Sep. 30, 2014
Recurring [Member]
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Dec. 31, 2013
Recurring [Member]
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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]
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Sep. 30, 2014
Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
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Dec. 31, 2013
Recurring [Member]
Significant Other Observable Inputs (Level 2) [Member]
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Sep. 30, 2014
Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
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Dec. 31, 2013
Recurring [Member]
Significant Unobservable Inputs (Level 3) [Member]
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| 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 | ||||||||||||||||||||||||
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