Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Taxes [Abstract] | |||
| U.S. federal taxes (benefit) at statutory rate | $ (2,178) | $ (10,670) | $ (15,644) |
| Unutilized net operating loss | 2,495 | 11,002 | 16,181 |
| Unutilized research credits | (445) | (1,308) | (1,515) |
| Non-deductible offset of Orphan Drug Credit | 249 | 383 | |
| Non-deductible stock based compensation | 6 | 673 | 567 |
| Other | $ 122 | $ 54 | $ 28 |
| Total | |||