Condensed Consolidated Balance Sheet Components - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Accrued royalty obligations	$ 1,622	$ 707
Accrued legal expenses	2,005	814
Accrued tax liabilities	1,884	1,470
Accrued professional services	2,991	1,791
Accrued clinical trials and studies	1,546	236
Purchases of property and equipment included in accrued expenses	4,210	343
Other	2,981	1,720
Total accrued expenses	$ 17,239	$ 7,081