Fair Value Measurements - Schedule of Activity of Major Classes of Assets Measured at Fair Value Using Level 3 Inputs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Other Liabilities: Contingent Consideration Obligation	$ 7,100	$ 0
Fair value adjustment to contingent consideration included in general and administrative expense	(2,781)
Cash paid upon achievement of milestone	1,250
Other Liabilities: Contingent Consideration Obligation	$ 8,631	7,100
Soha Systems, Inc.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration obligations		(1,600)
Cyberfend, Inc.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration obligations		$ (5,500)