Balance Sheet Components - Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents [Abstract]
Cash	$ 1,576	$ 1,307
Cash equivalents:
Money market accounts	148,604	27,847
Total cash and cash equivalents	$ 150,180	$ 29,154	$ 2,429	$ 1,314