Warrant Liability and Fair Value (Details) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
Apr. 12, 2011 |
Apr. 11, 2011 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
| Number of Units Sold | 8,000,000 | |||
| Number of warrants per unit | 1 | |||
| Warrant exercise price (in dollars per share) | $ 40.25 | |||
| Number of common stock shares per unit | 1 | |||
| Fair value of warrant liability | $ 1 | $ 289 | ||
| Transfers from Level 1 to Level 2 | 0 | 0 | ||
| Transfers from Level 2 to Level 1 | 0 | 0 | ||
| Transfers into Level 3 | 0 | 0 | ||
| Transfers out of Level 3 | 0 | 0 | ||
| Sponsor Warrants | ||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
| Warrants Issued During Period, Number | 4,000,000 | |||
| Fair Value, Inputs, Level 2 [Member] | ||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||
| Fair value of warrant liability | $ 1 | $ 289 | ||