Acquisitions - Additional Information (Details) - USD ($) $ in Thousands					3 Months Ended		6 Months Ended
	Apr. 01, 2019	May 18, 2018	May 01, 2018	Apr. 03, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill					$ 51,466		$ 51,466		$ 48,382
Purchase price of acquisition, cash							$ 6,764	$ 35,857
Mission Mode
Business Acquisition [Line Items]
Date of acquisition of business	Apr. 01, 2019
Total purchase price	$ 6,800				7,314
Note payable	600				550
Weighted average useful life of identified acquired intangible assets							6 years 10 months 24 days
Goodwill					2,918		$ 2,918
Business acquisition transaction costs					$ 100		$ 100
Mission Mode | Acquired Technology
Business Acquisition [Line Items]
Weighted average useful life of identified acquired intangible assets							3 years
Mission Mode | Customer Relationships
Business Acquisition [Line Items]
Weighted average useful life of identified acquired intangible assets							7 years
Mission Mode | Trade Names
Business Acquisition [Line Items]
Weighted average useful life of identified acquired intangible assets							1 year
Mission Mode | Maximum
Business Acquisition [Line Items]
Contingent payment	$ 1,000
Estimated useful life							7 years
Mission Mode | Minimum
Business Acquisition [Line Items]
Estimated useful life							1 year
UMS
Business Acquisition [Line Items]
Date of acquisition of business				Apr. 03, 2018
Purchase price of acquisition, cash				$ 31,900
PlanetRisk, Inc.
Business Acquisition [Line Items]
Date of acquisition of business			May 01, 2018
Purchase price of acquisition, cash			$ 2,000
Respond B.V.
Business Acquisition [Line Items]
Date of acquisition of business		May 18, 2018
Total purchase price		$ 2,300
Note payable		400
Purchase price of acquisition, cash		$ 2,000
UMS, PlanetRisk, Inc. and Respond B.V.
Business Acquisition [Line Items]
Business acquisition transaction costs						$ 300		$ 600