Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Collaboration and license revenue	$ 3,704	$ 3,794	$ 13,352	$ 46,715
Grant revenue	90		131	88
Total revenue	3,794	3,794	13,483	46,803
Operating expenses:
Research and development	24,454	19,046	66,464	66,855
General and administrative	8,458	8,556	24,982	26,255
Amortization of intangible assets	145	138	413	415
Total operating expenses	33,057	27,740	91,859	93,525
Loss from operations	(29,263)	(23,946)	(78,376)	(46,722)
Interest income	998	566	2,428	1,540
Other loss, net	(129)	(1)	(197)	(32)
Loss before income tax	(28,394)	(23,381)	(76,145)	(45,214)
Income tax (benefit) provision	(3,874)	11,670	(10,414)	16,368
Net loss	$ (24,520)	$ (35,051)	$ (65,731)	$ (61,582)
Net loss per common share, basic and diluted	$ (0.33)	$ (0.54)	$ (0.92)	$ (0.96)
Shares used in computing net loss per common share, basic and diluted	75,167,334	65,134,102	71,529,043	64,472,947