Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details)

v3.10.0.1
Summary of Significant Accounting Policies (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Accounting Policies [Abstract]          
Realized gains (losses) recognized on available-for-sale investments $ 0.8 $ 0.0 $ 0.7 $ 0.0  
Reduction in deferred tax asset value and valuation allowance         $ 3.7