Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Income Tax Disclosure [Abstract]      
Tax at federal statutory rate $ (27,173) $ (29,220) $ (21,142)
State statutory rate (net of federal benefit) (1,560) (1,728) (1,921)
Non-deductible stock compensation 2,334 (19) 619
Change in valuation allowance 24,332 30,571 22,184
Other 2,067 396 260
Income Tax Expense (Benefit) $ 0 $ 0 $ 0