Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue:
License and collaboration revenue—related party	$ 0	$ 10,981
Operating expenses:
Research and development	19,646	17,280
General and administrative	7,539	7,192
Total operating expenses	27,185	24,472
Operating loss	(27,185)	(13,491)
Other income, net	750	1,126
Loss before provision for income taxes	(26,435)	(12,365)
Provision for income taxes	8	12
Net loss	$ (26,443)	$ (12,377)
Net loss per share, basic and diluted (in dollars per share)	$ (0.78)	$ (0.38)
Weighted-average common shares outstanding, basic and diluted (in shares)	34,029	32,959
Comprehensive loss:
Net loss	$ (26,443)	$ (12,377)
Other comprehensive income:
Unrealized gain on available-for-sale securities	90	129
Comprehensive loss	$ (26,353)	$ (12,248)