Financial Statement Details - Summary of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 16,112	$ 21,198	$ 6,385	$ 9,894
Restricted cash	61	61	0	0
Total cash, cash equivalents and restricted cash	$ 16,173	$ 21,259	$ 6,385	$ 9,894