Income Taxes - Narrative (Details) - USD ($)
$ in Thousands |
12 Months Ended |
|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Dec. 31, 2012 |
| Operating Loss Carryforwards [Line Items] |
|
|
|
|
| Income tax provision |
$ 606
|
$ 640
|
$ 579
|
|
| Statutory federal rate |
34.00%
|
34.00%
|
34.00%
|
|
| Valuation allowance |
$ 84,167
|
$ 64,449
|
$ 47,858
|
$ 41,412
|
| Gross amount of unrealized net operating loss carryforwards |
49,000
|
|
|
|
| Tax-effected amount of unrealized net operating loss carryforwards |
18,000
|
|
|
|
| Increase in additional paid in capital |
18,000
|
|
|
|
| State and Local Jurisdiction |
|
|
|
|
| Operating Loss Carryforwards [Line Items] |
|
|
|
|
| Net operating loss carryforwards |
156,500
|
|
|
|
| State and Local Jurisdiction | Research Tax Credit Carryforward |
|
|
|
|
| Operating Loss Carryforwards [Line Items] |
|
|
|
|
| Research and development tax credit carryforwards |
400
|
|
|
|
| Federal |
|
|
|
|
| Operating Loss Carryforwards [Line Items] |
|
|
|
|
| Net operating loss carryforwards |
221,200
|
|
|
|
| Federal | Research Tax Credit Carryforward |
|
|
|
|
| Operating Loss Carryforwards [Line Items] |
|
|
|
|
| Research and development tax credit carryforwards |
$ 800
|
|
|
|