Convertible Senior Secured Notes - Term Loans (Details) - USD ($) $ in Thousands				1 Months Ended	12 Months Ended
	May. 03, 2013	Dec. 30, 2011	Jan. 26, 2011	May. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2011
Notes payable
Loss on extinguishment of debt					$ 2,338	$ 2,592	$ 9,550
Term loans
Notes payable
Aggregate amount								$ 30,000
Repayment of debt	$ 19,600			$ 19,600
Loss on extinguishment of debt							$ 1,200
Initial term loan facility
Notes payable
Drawdown under the secured credit facility			$ 15,000
Additional term loan facility
Notes payable
Drawdown under the secured credit facility		$ 15,000