Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Accrued clinical, manufacturing and other - related parties	$ 6,122	$ 2,997
Accrued clinical and manufacturing	11,681	2,396
Accrued compensation	4,666	3,435
Accrued professional and consulting fees	446	252
Accrued other	1,218	2,151
Accrued liabilities	$ 24,133	$ 11,231