Quarterly report pursuant to Section 13 or 15(d)

Revenue Related Disclosures - Additional Information (Details)

v3.19.2
Revenue Related Disclosures - Additional Information (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Jan. 01, 2018
Disaggregation Of Revenue [Line Items]            
Deferred revenue   $ 18.1   $ 18.1    
Deferred revenue added from new billings $ 8.8 8.1 $ 18.7 15.8    
United States            
Disaggregation Of Revenue [Line Items]            
Revenues 9.9 8.7 19.2 15.3    
South Africa            
Disaggregation Of Revenue [Line Items]            
Revenues 0.4 0.2 0.7 0.5    
Bahamas            
Disaggregation Of Revenue [Line Items]            
Revenues 0.4   0.7      
Adoption of Topic 606            
Disaggregation Of Revenue [Line Items]            
Deferred revenue         $ 24.2 $ 17.3
Recognition from Beginning Deferred Revenue Balance            
Disaggregation Of Revenue [Line Items]            
Deferred revenue recognized 9.2 6.4 15.7 11.7    
Recognition from New Billings of Deferred Revenue            
Disaggregation Of Revenue [Line Items]            
Deferred revenue recognized $ 1.0 $ 2.3 $ 4.0 $ 3.9