Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-controlling Interest [Member]
Beginning balance at Dec. 31, 2013	$ 86,222	$ 2	$ 187,957	$ (98,695)	$ (428)	$ (2,614)
Beginning balance, shares at Dec. 31, 2013		25,206,498
Issuance of common stock related to acquisitions	24,163	$ 0	24,163
Issuance of common stock related to acquisitions, shares		738,479
Issuance of common stock, net of repurchases	7,371	$ 0	7,371	0	0	0
Issuance of common stock, net of repurchases, shares		672,832
Vesting of restricted stock	454	$ 0	454	0	0	0
Stock-based compensation	37,273	0	37,273	0	0	0
Issuance of common stock in connection with employee stock purchase plan	3,332	$ 0	3,332	0	0	0
Issuance of common stock in connection with employee stock purchase plan, shares		188,068
Income tax benefit from employee stock option exercises	385	$ 0	385	0	0	0
Shares withheld for tax withholding on vesting of restricted stock units	(2,074)	0	(2,074)
Pre-combination service relating to acquired Skyfence option plan	354	0	354	0	0	0
Purchase of additional ownership interest in Incapsula, Inc.	0	$ 0	(2,827)	0	0	2,827
Purchase of additional ownership interest in Incapsula, Inc. Shares		89,603
Components of other comprehensive income (loss), net of tax
Change in unrealized loss on investments	(59)	$ 0	0	0	(59)	0
Change in unrealized loss on derivatives	(1,002)	0	0	0	(1,002)	0
Net loss	(59,176)	0	0	(58,963)	0	(213)
Comprehensive loss	(60,237)
Ending balance at Dec. 31, 2014	97,243	$ 2	256,388	(157,658)	(1,489)	0
Ending balance, shares at Dec. 31, 2014		26,895,480
Proceeds from follow-on public offering, net of offering costs	127,741	$ 1	127,740	0	0	0
Proceeds from follow-on public offering, net of offering costs, shares		3,450,000
Issuance of common stock, net of repurchases	18,724	$ 0	18,724	0	0	0
Issuance of common stock, net of repurchases, shares		670,844
Vesting of restricted stock	767	$ 0	767	0	0	0
Vesting of restricted stock, shares		706,121
Stock-based compensation	50,964	$ 0	50,964	0	0	0
Issuance of common stock in connection with employee stock purchase plan	4,785	$ 0	4,785	0	0	0
Issuance of common stock in connection with employee stock purchase plan, shares		114,699
Income tax benefit from employee stock option exercises	165	$ 0	165	0	0	0
Shares withheld for tax withholding on vesting of restricted stock units	(11,464)	0	(11,464)
Components of other comprehensive income (loss), net of tax
Change in unrealized loss on investments	(249)	0	0	0	(249)	0
Change in unrealized loss on derivatives	407	0	0	0	407	0
Net loss	(48,882)	0	0	(48,882)	0	0
Comprehensive loss	(48,724)	0	0
Ending balance at Dec. 31, 2015	240,201	$ 3	448,069	(206,540)	(1,331)	0
Ending balance, shares at Dec. 31, 2015		31,837,144
Issuance of common stock related to acquisitions	0	$ 0	0	0	0	0
Issuance of common stock related to acquisitions, shares		206,499
Issuance of common stock, net of repurchases	5,402		5,402
Issuance of common stock, net of repurchases, shares		843,724
Stock-based compensation	59,750	$ 0	59,750	0	0	0
Issuance of common stock in connection with employee stock purchase plan	5,831		5,831	0	0	0
Issuance of common stock in connection with employee stock purchase plan, shares		201,623
Income tax benefit from employee stock option exercises	36	$ 0	36	0	0	0
Shares withheld for tax withholding on vesting of restricted stock units	(8,831)	0	(8,831)	0	0	0
Components of other comprehensive income (loss), net of tax
Change in unrealized loss on investments	(103)	0	0	0	(103)	0
Change in unrealized loss on derivatives	(44)	0	0	0	(44)
Net loss	(70,279)	0	0	(70,279)	0	0
Comprehensive loss	(70,426)	0	0	0		0
Ending balance at Dec. 31, 2016	$ 231,963	$ 3	$ 510,257	$ (276,819)	$ (1,478)	$ 0
Ending balance, shares at Dec. 31, 2016		33,088,990