Acquisitions - Summary of Allocation of Purchase Consideration and Estimated Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Jul. 29, 2019	Apr. 01, 2019	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Assets acquired
Goodwill			$ 90,706		$ 90,706		$ 48,382
Consideration paid
Cash paid					58,419	$ 35,857
Contingent consideration					550
Mission Mode
Assets acquired
Accounts receivable				$ 295
Other assets				7
Property and equipment				6
Goodwill			2,900	2,918	2,900
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
NC4 Inc. and NC4 Public Sector LLC
Assets acquired
Accounts receivable			2,611		2,611
Other current assets			530		530
Property and equipment			75		75
Goodwill			40,424		40,424
Total assets acquired			92,950		92,950
Liabilities assumed
Deferred revenue			7,540		7,540
Other current liabilities			917		917
Net assets acquired			84,493		84,493
Consideration paid
Cash paid, net of cash acquired	$ 51,700
Cash paid			51,655
Fair value of common stock issued			32,838
Total	$ 84,500		84,493
Trade Names | Mission Mode
Assets acquired
Intangible assets other than goodwill				220
Trade Names | NC4 Inc. and NC4 Public Sector LLC
Assets acquired
Intangible assets other than goodwill			8,610		8,610
Acquired Technology | Mission Mode
Assets acquired
Intangible assets other than goodwill				310
Acquired Technology | NC4 Inc. and NC4 Public Sector LLC
Assets acquired
Intangible assets other than goodwill			5,210		5,210
Customer Relationships | Mission Mode
Assets acquired
Intangible assets other than goodwill				$ 4,600
Customer Relationships | NC4 Inc. and NC4 Public Sector LLC
Assets acquired
Intangible assets other than goodwill			$ 35,490		$ 35,490