Consolidated Statements of Operations - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Contract revenue - related party	$ 616,000	$ 1,057,000	$ 0
Total revenue	616,000	1,057,000	0
Expenses
Research and development	62,288,000	29,092,000	9,944,000
General and administrative	16,700,000	13,934,000	11,396,000
Total expenses	78,988,000	43,026,000	21,340,000
Loss from operations	(78,372,000)	(41,969,000)	(21,340,000)
Other income, net	187,000	57,000	27,000
Net loss	(78,185,000)	(41,912,000)	(21,313,000)
Net loss attributable to common shareholders	$ (78,185,000)	$ (41,912,000)	$ (21,313,000)
Basic and diluted net loss per share (usd per share)	$ (4.54)	$ (2.68)	$ (2.00)
Shares used in computing basic and diluted net loss per share (in shares)	17,228	15,651	10,667