|
Income taxes (Details 2) (USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2012
|
|---|---|
| Operating loss carryforwards | |
| Net operating loss carryforwards | $ 384,401 |
|
2027
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | 63,565 |
|
2028
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | 104,436 |
|
2029
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | 85,277 |
|
2030
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | 25,805 |
|
2031
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | 59,265 |
|
2032
|
|
| Operating loss carryforwards | |
| Net operating loss carryforwards | $ 46,053 |