Income Taxes (Details 3) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforwards	$ 44,587	$ 66,167
Stock based compensation	1,767	0
Fair value royalty agreements	2,435	2,130
Other	1,025	1,039
Total deferred tax assets	49,814	69,336
Valuation allowances	(45,516)	(57,980)
Net deferred tax assets	4,298	11,356
Deferred tax liabilities:
Amortization of IPR&D	(5,649)	(11,356)
Total deferred tax liabilities	(5,649)	(11,356)
Net deferred tax assets (liabilities)	$ (1,351)	$ 0