Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements of Comprehensive Loss
Net loss	$ (24,288)us-gaap_NetIncomeLoss	$ (15,943)us-gaap_NetIncomeLoss
Other comprehensive income/ (loss):
Unrealized gain on available-for-sale securities	97	1
Other comprehensive gain before income taxes	97	1
Other comprehensive income	97	1
Comprehensive loss	$ (24,191)us-gaap_ComprehensiveIncomeNetOfTax	$ (15,942)us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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