Income Taxes Income Taxes - Schedule of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carry forwards	$ 57,177	$ 56,942
Stock—based compensation	6,706	7,636
Development costs	20,101	6,776
Other	2,108	1,301
Total deferred tax assets, gross	86,092	72,655
Deferred tax liability:
Depreciation	0	(551)
Net deferred tax assets	86,092	72,104
Valuation allowance	(86,092)	(72,104)
Deferred tax assets, net	$ 0	$ 0