Financial Statement Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Depreciation and amortization	$ 16,214	$ 14,663	$ 13,467
Amortization expense of Intangible Assets	$ 800	1,100
Developed Technology
Finite Lived Intangible Assets [Line Items]
Weighted average amortization periods	2 years 4 months 24 days
Property and equipment
Finite Lived Intangible Assets [Line Items]
Depreciation and amortization	$ 15,400	$ 13,600	$ 12,900