Business Combinations - Summary of Allocation of Purchase Consideration and Estimated Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands						12 Months Ended
	Jul. 29, 2019	Apr. 01, 2019	May 18, 2018	May 01, 2018	Apr. 03, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets acquired
Goodwill						$ 91,421	$ 48,382	$ 31,328
Consideration paid
Cash paid						58,419	$ 35,857	$ 21,235
MissionMode Solutions, Inc.
Assets acquired
Accounts receivable						295
Other assets						7
Property and equipment						6
Goodwill		$ 2,900				2,918
Total assets acquired						8,356
Liabilities assumed
Accounts payable and accrued expenses						152
Deferred revenue						880
Other liabilities						10
Net assets acquired						7,314
Consideration paid
Cash paid, net of cash acquired						6,764
Contingent consideration		600				550
Total		$ 6,800				7,314
MissionMode Solutions, Inc. | Trade Names
Assets acquired
Intangible assets other than goodwill						220
MissionMode Solutions, Inc. | Acquired Technology
Assets acquired
Intangible assets other than goodwill						310
MissionMode Solutions, Inc. | Customer Relationships
Assets acquired
Intangible assets other than goodwill						4,600
NC4 Inc. and NC4 Public Sector LLC
Assets acquired
Accounts receivable						2,611
Other current assets						530
Property and equipment						75
Goodwill	$ 40,400					40,384
Total assets acquired						92,910
Liabilities assumed
Deferred revenue						7,540
Other current liabilities						917
Net assets acquired						84,453
Consideration paid
Cash paid, net of cash acquired	51,700
Cash paid						51,655
Fair value of common stock issued						32,798
Total	$ 84,500					84,453
NC4 Inc. and NC4 Public Sector LLC | Trade Names
Assets acquired
Intangible assets other than goodwill						8,610
NC4 Inc. and NC4 Public Sector LLC | Acquired Technology
Assets acquired
Intangible assets other than goodwill						5,210
NC4 Inc. and NC4 Public Sector LLC | Customer Relationships
Assets acquired
Intangible assets other than goodwill						$ 35,490
UMS
Assets acquired
Accounts receivable					$ 3,793
Other assets					2,069
Property and equipment					27
Goodwill					18,278
Total assets acquired					41,967
Liabilities assumed
Accounts payable and accrued expenses					3,852
Deferred revenue					6,130
Other liabilities					101
Net assets acquired					31,884
Consideration paid
Cash paid, net of cash acquired					31,884
Cash paid					31,900
Total					31,884
UMS | Trade Names
Assets acquired
Intangible assets other than goodwill					470
UMS | Acquired Technology
Assets acquired
Intangible assets other than goodwill					930
UMS | Customer Relationships
Assets acquired
Intangible assets other than goodwill					$ 16,400
PlanetRisk, Inc.
Assets acquired
Accounts receivable				$ 2,862
Property and equipment				488
Goodwill				228
Total assets acquired				5,988
Liabilities assumed
Accounts payable and accrued expenses				717
Deferred revenue				3,030
Other liabilities				220
Net assets acquired				2,021
Consideration paid
Cash paid, net of cash acquired				2,021
Cash paid				2,000
Total				2,021
PlanetRisk, Inc. | Acquired Technology
Assets acquired
Intangible assets other than goodwill				110
PlanetRisk, Inc. | Customer Relationships
Assets acquired
Intangible assets other than goodwill				$ 2,300
Respond B.V.
Assets acquired
Accounts receivable			$ 86
Other assets			87
Property and equipment			19
Goodwill			1,193
Total assets acquired			3,215
Liabilities assumed
Accounts payable and accrued expenses			226
Deferred revenue			240
Other liabilities			414
Net assets acquired			2,335
Consideration paid
Cash paid, net of cash acquired			1,952
Note payable			383
Cash paid			2,000
Contingent consideration			400
Total			2,335
Respond B.V. | Trade Names
Assets acquired
Intangible assets other than goodwill			90
Respond B.V. | Acquired Technology
Assets acquired
Intangible assets other than goodwill			140
Respond B.V. | Customer Relationships
Assets acquired
Intangible assets other than goodwill			$ 1,600