Income Taxes - Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Research Tax Credit Carryforward
Operating loss and tax credit carryforwards
Tax credit carryforwards	$ 1.3	$ 0.4
Federal
Operating loss and tax credit carryforwards
Net operating loss carryforwards	36.5	17.7
State
Operating loss and tax credit carryforwards
Net operating loss carryforwards	34.4	$ 21.6
Foreign | Australian Taxation Office
Operating loss and tax credit carryforwards
Net operating loss carryforwards	$ 1.2