| Year ended December 31, | Six Months ended June 30, | |||||||||||||||||||||||
| (dollars in thousands) | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | ||||||||||||||||||
| Ratio of earnings to fixed charges | ||||||||||||||||||||||||
| Earnings: | ||||||||||||||||||||||||
| Income (loss) before income taxes and cumulative effect of change in accounting principle | $ | 75,479 | $ | (22,743 | ) | $ | (39,459 | ) | $ | (26,857 | ) | (9,887 | ) | $ | (15,399 | ) | ||||||||
| Add: | ||||||||||||||||||||||||
| Fixed charges | 10 | — | — | — | — | — | ||||||||||||||||||
| Amortization of capitalized interest | — | — | — | — | — | — | ||||||||||||||||||
| Distributed income of equity investees | 23,599 | — | — | — | — | — | ||||||||||||||||||
| Share of pre-tax losses of equity investees for which charges arising from guarantees are included in fixed charges | — | — | — | — | — | — | ||||||||||||||||||
| Less: | — | — | — | — | — | |||||||||||||||||||
| Capitalized interest | — | — | — | — | — | — | ||||||||||||||||||
| Preference security dividend requirements of consolidated subsidiaries | — | — | — | — | — | — | ||||||||||||||||||
| Non-controlling interest in pre-tax income of subsidiaries that have not incurred fixed charges | — | — | — | — | — | — | ||||||||||||||||||
| Total earnings | $ | 99,088 | $ | (22,743 | ) | $ | (39,459 | ) | $ | (26,857 | ) | (9,887 | ) | (15,399 | ) | |||||||||
| Fixed charges: | ||||||||||||||||||||||||
| Total interest expense | $ | 10 | $ | — | $ | — | $ | — | — | — | ||||||||||||||
| Capitalized interest | — | — | — | — | — | — | ||||||||||||||||||
| Interest factor in rents | — | — | — | — | — | — | ||||||||||||||||||
| Total fixed charges | $ | — | $ | — | $ | — | $ | — | — | — | ||||||||||||||
| Ratio of earnings to fixed charges | 9,909 | % | N/ | A | N/ | A | N/ | A | N/ | A | N/ | A | ||||||||||||
