Balance Sheet Components - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 106,046	$ 100,348
Restricted cash included in other assets	300	188
Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows	$ 106,346	$ 100,536	$ 109,207	$ 150,405