Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2017	Mar. 31, 2017	Mar. 31, 2016
Finite Lived Intangible Assets [Line Items]
Goodwill allocated to disposal of assets		$ 1,059,000
Goodwill impairments		0	$ 0
Impairment of intangible assets		$ 0	$ 0
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life		7 years
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life		10 years
Acquired Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted average remaining useful life		6 years 9 months 18 days
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Weighted average remaining useful life		6 years 8 months 12 days
Trade Name and Other [Member]
Finite Lived Intangible Assets [Line Items]
Weighted average remaining useful life		6 years 8 months 12 days
Skyfence Cloud Access Security Broker Business [Member]
Finite Lived Intangible Assets [Line Items]
Goodwill allocated to disposal of assets	$ 1,100,000
Intangible assets derecognized in connection with disposal of assets	$ 4,500,000