CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Government contracts	$ 0	$ 102	$ 0	$ 2,182
Research and development collaborations	8,352	3,129	20,764	7,772
Total revenue	8,352	3,231	20,764	9,954
Expenses:
Research and development	41,862	52,983	118,779	186,839
General and administrative	8,118	13,556	25,911	38,183
Total expenses	49,980	66,539	144,690	225,022
Loss from operations	(41,628)	(63,308)	(123,926)	(215,068)
Other income (expense):
Investment income	531	554	1,528	1,701
Interest expense	(3,520)	(3,511)	(10,549)	(9,457)
Other income (expense)	10	11	20	(33)
Net loss	$ (44,607)	$ (66,254)	$ (132,927)	$ (222,857)
Basic and diluted net loss per share	$ (0.15)	$ (0.24)	$ (0.47)	$ (0.82)
Basic and diluted weighted average number of common shares outstanding	296,435	271,064	284,767	270,669