Nature of Operations (Details 2) $ in Millions |
9 Months Ended | 12 Months Ended | |
|---|---|---|---|
|
Sep. 30, 2015
USD ($)
|
Sep. 30, 2014
USD ($)
|
Dec. 31, 2014
USD ($)
item
|
|
| Nature Of Operation | |||
| Increase in restricted cash related to sale/leaseback transactions | $ 29.7 | ||
| Gross proceeds from shares of common stock sold in an underwritten public offering | $ 176.7 | $ 176.7 | |
| Number of underwritten public offerings | item | 3 | ||
| Net proceeds from public offering | 165.7 | $ 165.7 | |
| Net proceeds from previously issued common stock warrants | $ 18.3 | $ 18.3 | |
| Minimum period for which we believe that our current cash, cash equivalents, cash generated from future sales, and cash generated from the exercise of outstanding warrants will provide sufficient liquidity to fund operations | 12 months | ||