Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Secure DNA	Mandiant, Inc.	nPulse Technologies	Additional Paid-In Capital	Additional Paid-In Capital Secure DNA	Additional Paid-In Capital Mandiant, Inc.	Additional Paid-In Capital nPulse Technologies	Notes Receivable from Stockholders	Accumulated Other Comprehensive Loss	Accumulated Deficit	Treasury Stock	Convertible Preferred Stock	Common Stock	Common Stock Secure DNA	Common Stock Mandiant, Inc.	Common Stock nPulse Technologies
Beginning balance, value at Dec. 31, 2012	$ 5,390				$ 109,252				$ (1,003)	$ 0	$ (102,867)		$ 6	$ 2
Beginning balance (in shares) at Dec. 31, 2012													64,115	22,435
Issuance of common stock	320,979				320,977									$ 2
Issuance of common stock (in shares)														17,450
Conversion of convertible preferred stock to common stock in connection with initial public offering	0				(1)								$ (6)	$ 7
Conversion of convertible preferred stock to common stock in connection with initial public offering (in shares)													(64,590)	74,222
Conversion of preferred stock warrant to common stock warrant in connection with initial public offering	10,067				10,067
Issuance of common stock for equity awards, net of repurchases	2,394				2,393									$ 1
Issuance of common stock for equity awards, net of repurchases (in shares)														6,680
Issuance of common stock related to acquisitions	791,917	$ 800	$ 791,117			$ 800	$ 791,115									$ 2
Issuance of common stock related to acquisitions (in shares)															50	16,921
Payment of note receivable from stockholder, net of early exercises	1,831				828				1,003
Net proceeds from issuance of Series F convertible preferred stock	4,994				4,994
Net proceeds from issuance of Series F convertible preferred stock (in shares)													475
Vesting of early exercise of equity awards	2,307				2,307
Stock-based compensation	28,858				28,858
Net loss	(120,635)										(120,635)
Ending balance, value at Dec. 31, 2013	1,048,102				1,271,590				0	0	(223,502)		$ 0	$ 14
Ending balance (in shares) at Dec. 31, 2013													0	137,758
Issuance of common stock	444,295				444,295
Issuance of common stock (in shares)														5,582
Issuance of common stock for equity awards, net of repurchases	20,659				20,658									$ 1
Issuance of common stock for equity awards, net of repurchases (in shares)														8,030
Issuance of common stock related to acquisitions	1,398			$ 1,398				$ 1,398
Issuance of common stock related to acquisitions (in shares)																	296
Issuance of common stock related to employee stock purchase plan			21,228				21,228
Issuance of common stock related to employee stock purchase plan (in shares)														1,194
Assumption of vested options related acquisition			$ 3,135				$ 3,135
Vesting of early exercise of equity awards	4,390				4,390
Stock-based compensation	151,852				151,852
Unrealized loss on investments	(441)									(441)
Net loss	(443,790)										(443,790)
Ending balance, value at Dec. 31, 2014	1,250,828				1,918,546				0	(441)	(667,292)		$ 0	$ 15
Ending balance (in shares) at Dec. 31, 2014													0	152,860
Issuance of common stock for equity awards, net of repurchases	27,063				27,062									$ 1
Issuance of common stock for equity awards, net of repurchases (in shares)														7,786
Issuance of common stock related to acquisitions	0			$ 210,401				$ 210,401
Issuance of common stock related to employee stock purchase plan	21,880				21,880
Excess tax benefit on vesting of awards and options exercised	809				809
Issuance of common stock related to employee stock purchase plan (in shares)														997
Prepaid forward stock purchase	(150,000)											$ (150,000)
Vesting of early exercise of equity awards	2,271				2,271
Stock-based compensation	222,119				222,119
Unrealized loss on investments	(1,784)									(1,784)
Net loss	(539,215)										(539,215)
Ending balance, value at Dec. 31, 2015	$ 1,044,372				$ 2,403,088				$ 0	$ (2,225)	$ (1,206,507)	$ (150,000)	$ 0	$ 16
Ending balance (in shares) at Dec. 31, 2015													0	161,643