Balance Sheet Components - Property and Equipment (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Property and Equipment, net    
Property and equipment, gross $ 3,977 $ 1,980
Less: accumulated depreciation and amortization (729) (135)
Property and equipment, net 3,248 1,845
Laboratory equipment    
Property and Equipment, net    
Property and equipment, gross 1,868 829
Computer equipment and purchased software    
Property and Equipment, net    
Property and equipment, gross 58 18
Leasehold improvements    
Property and Equipment, net    
Property and equipment, gross $ 2,051 74
Construction in progress    
Property and Equipment, net    
Property and equipment, gross   $ 1,059