Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	NC4 Inc. and NC4 Public Sector LLC	Common Stock	Common Stock NC4 Inc. and NC4 Public Sector LLC	Additional Paid-in Capital	Additional Paid-in Capital NC4 Inc. and NC4 Public Sector LLC	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2017	$ 55,991		$ 28		$ 164,995		$ (109,252)	$ 220
Balance, shares at Dec. 31, 2017			28,330,460
Cumulative effect of adoption of ASU 2014-09, net of taxes	9,097						9,097
Stock-based compensation	6,694				6,694
Vesting of restricted stock units, shares			222,624
Restricted stock units withheld to settle employee tax withholding liability	(1,022)				(1,022)
Restricted stock units withheld to settle employee tax withholding liability, shares			(27,771)
Exercise of stock options	1,466		$ 1		1,465
Exercise of stock options, shares			153,744
Issuance of shares under employee stock purchase plan	881				881
Issuance of shares under employee stock purchase plan, shares			44,193
Other comprehensive income (loss)	(267)							(267)
Net loss	(12,342)						(12,342)
Balance at Mar. 31, 2018	60,498		$ 29		173,013		(112,497)	(47)
Balance, shares at Mar. 31, 2018			28,723,250
Balance at Dec. 31, 2017	55,991		$ 28		164,995		(109,252)	220
Balance, shares at Dec. 31, 2017			28,330,460
Net loss	(37,710)
Balance at Sep. 30, 2018	47,723		$ 29		187,909		(137,865)	(2,350)
Balance, shares at Sep. 30, 2018			29,625,465
Balance at Dec. 31, 2017	$ 55,991		$ 28		164,995		(109,252)	220
Balance, shares at Dec. 31, 2017			28,330,460
Exercise of stock options, shares	778,370
Balance at Dec. 31, 2018	$ 42,158		$ 30		194,866		(147,670)	(5,068)
Balance, shares at Dec. 31, 2018			29,700,192
Balance at Mar. 31, 2018	60,498		$ 29		173,013		(112,497)	(47)
Balance, shares at Mar. 31, 2018			28,723,250
Stock-based compensation	10,022				10,022
Vesting of restricted stock units, shares			221,624
Restricted stock units withheld to settle employee tax withholding liability	(2,750)				(2,750)
Restricted stock units withheld to settle employee tax withholding liability, shares			(53,326)
Exercise of stock options	4,369				4,369
Exercise of stock options, shares			367,819
Other comprehensive income (loss)	(2,384)							(2,384)
Net loss	(16,918)						(16,918)
Balance at Jun. 30, 2018	52,837		$ 29		184,654		(129,415)	(2,431)
Balance, shares at Jun. 30, 2018			29,259,367
Stock-based compensation	3,541				3,541
Vesting of restricted stock units, shares			226,883
Restricted stock units withheld to settle employee tax withholding liability	(4,149)				(4,149)
Restricted stock units withheld to settle employee tax withholding liability, shares			(73,372)
Exercise of stock options	2,986				2,986
Exercise of stock options, shares			182,263
Issuance of shares under employee stock purchase plan	877				877
Issuance of shares under employee stock purchase plan, shares			30,324
Other comprehensive income (loss)	81							81
Net loss	(8,450)						(8,450)
Balance at Sep. 30, 2018	47,723		$ 29		187,909		(137,865)	(2,350)
Balance, shares at Sep. 30, 2018			29,625,465
Balance at Dec. 31, 2018	42,158		$ 30		194,866		(147,670)	(5,068)
Balance, shares at Dec. 31, 2018			29,700,192
Issuance of common stock, net of cost	138,839		$ 3		138,836
Issuance of common stock, net of cost, shares			2,645,000
Stock-based compensation	7,849				7,849
Vesting of restricted stock units, shares			16,849
Restricted stock units withheld to settle employee tax withholding liability	(333)				(333)
Restricted stock units withheld to settle employee tax withholding liability, shares			(5,301)
Exercise of stock options	8,746				8,746
Exercise of stock options, shares			501,083
Issuance of shares under employee stock purchase plan	1,283				1,283
Issuance of shares under employee stock purchase plan, shares			24,266
Other comprehensive income (loss)	22							22
Net loss	(14,134)						(14,134)
Balance at Mar. 31, 2019	184,430		$ 33		351,247		(161,804)	(5,046)
Balance, shares at Mar. 31, 2019			32,882,089
Balance at Dec. 31, 2018	$ 42,158		$ 30		194,866		(147,670)	(5,068)
Balance, shares at Dec. 31, 2018			29,700,192
Exercise of stock options, shares	851,467
Net loss	$ (39,118)
Balance at Sep. 30, 2019	211,098		$ 34		404,676		(186,788)	(6,824)
Balance, shares at Sep. 30, 2019			33,778,616
Balance at Mar. 31, 2019	184,430		$ 33		351,247		(161,804)	(5,046)
Balance, shares at Mar. 31, 2019			32,882,089
Issuance of common stock, net of cost	(5)				(5)
Stock-based compensation	8,282				8,282
Vesting of restricted stock units, shares			25,720
Restricted stock units withheld to settle employee tax withholding liability	(116)				(116)
Restricted stock units withheld to settle employee tax withholding liability, shares			(1,410)
Exercise of stock options	4,741				4,741
Exercise of stock options, shares			243,920
Other comprehensive income (loss)	271							271
Net loss	(12,063)						(12,063)
Balance at Jun. 30, 2019	185,540		$ 33		364,149		(173,867)	(4,775)
Balance, shares at Jun. 30, 2019			33,150,319
Issuance of common stock in connection with acquisition		$ 32,838				$ 32,838
Issuance of common stock in connection with acquisition, shares				320,998
Stock-based compensation	8,383				8,383
Vesting of restricted stock units, shares			229,284
Restricted stock units withheld to settle employee tax withholding liability	(4,082)				(4,082)
Restricted stock units withheld to settle employee tax withholding liability, shares			(46,664)
Exercise of stock options	2,335		$ 1		2,334
Exercise of stock options, shares			106,464
Issuance of shares under employee stock purchase plan	1,054				1,054
Issuance of shares under employee stock purchase plan, shares			18,215
Other comprehensive income (loss)	(2,049)							(2,049)
Net loss	(12,921)						(12,921)
Balance at Sep. 30, 2019	$ 211,098		$ 34		$ 404,676		$ (186,788)	$ (6,824)
Balance, shares at Sep. 30, 2019			33,778,616