Commitments and Contingencies (401(k) Retirement Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Compensation expense related to 401(k) retirement plan	$ 0.7	$ 1.0	$ 1.0
Up to 2 Percent
Defined Contribution Plan Disclosure [Line Items]
Company match	100.00%
Employee contribution	2.00%
From 4 to 8 Percent
Defined Contribution Plan Disclosure [Line Items]
Company match	50.00%
From 4 to 8 Percent | Minimum
Defined Contribution Plan Disclosure [Line Items]
Employee contribution	5.00%
From 4 to 8 Percent | Maximum
Defined Contribution Plan Disclosure [Line Items]
Employee contribution	8.00%