Commitments and Contingencies - Litigation (Details) - Settled litigation - Finjan, Inc. patent infringement
$ in Thousands
1 Months Ended
Mar. 21, 2018
patent
Apr. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Patents      
Number of patents seeking judgment the Company infringed asserted patents 4    
Number of patents seeking preliminary and permanent injunction against the Company preventing continued infringement 1    
Accrual      
Accrued liability | $     $ 3,900
Payment      
First payment of settlement amount | $   $ 1,300  
Minimum      
Patents      
Number of patents allegedly infringed 4