Financial Statement Components - Components of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Cash And Cash Equivalents [Abstract]
Cash	$ 19,926	$ 18,522
Money market funds	119,148	119,066
Total cash and cash equivalents	$ 139,074	$ 137,588	$ 114,152	$ 113,182