Income Taxes - Components of the Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Taxes
Operating loss carryforwards	$ 56,832	$ 46,432
Tax credit carryforwards	9,428	5,627
Other	7,710	5,698
Deferred Tax Assets, Gross	73,970	57,757
Valuation allowance	$ (73,970)	$ (57,757)