|
Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2012
|
Dec. 31, 2011
|
|---|---|---|
| Assets | ||
| Assets | $ 75,697 | $ 65,304 |
|
Cash [Member]
|
||
| Assets | ||
| Assets | 2,440 | 5,725 |
|
Money market securities [Member]
|
||
| Assets | ||
| Assets | 15,949 | 21,163 |
|
Corporate bonds and commercial paper [Member]
|
||
| Assets | ||
| Assets | 57,308 | 38,416 |
|
Warrants [Member]
|
||
| Liabilities | ||
| Liabilities | 3,422 | 7,881 |
|
Level 1 [Member]
|
||
| Assets | ||
| Assets | 18,389 | 26,888 |
|
Level 1 [Member] | Cash [Member]
|
||
| Assets | ||
| Assets | 2,440 | 5,725 |
|
Level 1 [Member] | Money market securities [Member]
|
||
| Assets | ||
| Assets | 15,949 | 21,163 |
|
Level 1 [Member] | Corporate bonds and commercial paper [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 1 [Member] | Warrants [Member]
|
||
| Liabilities | ||
| Liabilities | ||
|
Level 2 [Member]
|
||
| Assets | ||
| Assets | 57,308 | 38,416 |
|
Level 2 [Member] | Cash [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 2 [Member] | Money market securities [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 2 [Member] | Corporate bonds and commercial paper [Member]
|
||
| Assets | ||
| Assets | 57,308 | 38,416 |
|
Level 2 [Member] | Warrants [Member]
|
||
| Liabilities | ||
| Liabilities | ||
|
Level 3 [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 3 [Member] | Cash [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 3 [Member] | Money market securities [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 3 [Member] | Corporate bonds and commercial paper [Member]
|
||
| Assets | ||
| Assets | ||
|
Level 3 [Member] | Warrants [Member]
|
||
| Liabilities | ||
| Liabilities | $ 3,422 | $ 7,881 |