Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Lease assets	$ 525	$ 800
Operating lease, liability	533	900
Operating lease, liability, noncurrent	$ 34	$ 200
California
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Company original incorporation date of incorporation	2012-04
Company Incorporation place	California
Delaware
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Company Incorporation place	Delaware
Company reincorporation incorporation date of incorporation	2017-07