9. Fair value measurements (Details) (USD $)
In Thousands, unless otherwise specified |
Sep. 30, 2013
|
Dec. 31, 2012
|
---|---|---|
Assets: | ||
Assets | $ 128 | $ 189 |
Liabilities: | ||
Liabilities | 6,674 | 5,059 |
Commodity contracts [Member]
|
||
Assets: | ||
Assets | 128 | 189 |
Liabilities: | ||
Liabilities | 44 | 167 |
Warrants [Member]
|
||
Liabilities: | ||
Liabilities | 5,491 | 4,892 |
Conversion Features [Member]
|
||
Liabilities: | ||
Liabilities | 1,139 | |
Level 1 [Member]
|
||
Assets: | ||
Assets | 128 | 189 |
Liabilities: | ||
Liabilities | 44 | 167 |
Level 1 [Member] | Commodity contracts [Member]
|
||
Assets: | ||
Assets | 128 | 189 |
Liabilities: | ||
Liabilities | 44 | 167 |
Level 1 [Member] | Warrants [Member]
|
||
Liabilities: | ||
Liabilities | 0 | 0 |
Level 1 [Member] | Conversion Features [Member]
|
||
Liabilities: | ||
Liabilities | 0 | |
Level 2 [Member]
|
||
Assets: | ||
Assets | 0 | 0 |
Liabilities: | ||
Liabilities | 0 | 0 |
Level 2 [Member] | Commodity contracts [Member]
|
||
Assets: | ||
Assets | 0 | 0 |
Liabilities: | ||
Liabilities | 0 | 0 |
Level 2 [Member] | Warrants [Member]
|
||
Liabilities: | ||
Liabilities | 0 | 0 |
Level 2 [Member] | Conversion Features [Member]
|
||
Liabilities: | ||
Liabilities | 0 | |
Level 3 [Member]
|
||
Assets: | ||
Assets | 0 | 0 |
Liabilities: | ||
Liabilities | 6,630 | 4,892 |
Level 3 [Member] | Commodity contracts [Member]
|
||
Assets: | ||
Assets | 0 | 0 |
Liabilities: | ||
Liabilities | 0 | 0 |
Level 3 [Member] | Warrants [Member]
|
||
Liabilities: | ||
Liabilities | 5,491 | 4,892 |
Level 3 [Member] | Conversion Features [Member]
|
||
Liabilities: | ||
Liabilities | $ 1,139 |