Equity Incentive Plans - Summary of Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 3,272	$ 689	$ 70
2010 Plan and 2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	2,850	620	70
2010 Plan and 2014 Plan | Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	1,147	275	47
2010 Plan and 2014 Plan | General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 1,703	$ 345	$ 23