Balance Sheet Components - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 133,829	$ 100,348	$ 125,025
Restricted cash included in other assets	175		187
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statement of cash flows	$ 134,004	$ 100,536	$ 125,212	$ 109,207