Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue:
Collaboration and license revenue	$ 5,876	$ 38,938	$ 9,648	$ 42,921
Grant revenue	41	41	41	88
Total revenue	5,917	38,979	9,689	43,009
Operating expenses:
Research and development	21,440	26,882	42,011	47,809
General and administrative	8,245	8,700	16,523	17,699
Amortization of intangible assets	136	140	268	277
Total operating expenses	29,821	35,722	58,802	65,785
(Loss) income from operations	(23,904)	3,257	(49,113)	(22,776)
Interest income, net	780	520	1,430	974
Other loss, net	(64)	(9)	(68)	(31)
(Loss) income before income tax	(23,188)	3,768	(47,751)	(21,833)
Income tax (benefit) provision	(3,788)	1,472	(6,540)	4,698
Net (loss) income	$ (19,400)	$ 2,296	$ (41,211)	$ (26,531)
Net (loss) income per common share, basic	$ (0.27)	$ 0.04	$ (0.59)	$ (0.41)
Net (loss) income per common share, diluted	$ (0.27)	$ 0.03	$ (0.59)	$ (0.41)
Shares used in computing net loss per common share, basic	71,101,336	64,434,903	69,679,746	64,138,737
Shares used in computing net loss per common share, diluted	71,101,336	71,473,807	69,679,746	64,138,737