Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Revenues
Collaborative revenues	$ 61		$ 120		$ 1,145
Operating expenses
License fees	2,500
Research and development	73,869		60,602		26,722
General and administrative	88,304		32,748		12,720
Total operating expenses	164,673		93,350		39,442
Loss from operations	(164,612)		(93,230)		(38,297)
Interest income, net	499		755		349
Loss before income taxes	(164,113)		(92,475)		(37,948)
Income tax expense	330
Net loss	$ (164,443)		$ (92,475)		$ (37,948)
Net loss per common share, basic and diluted	$ (1.63)	[1]	$ (0.95)	[1]	$ (0.44)
Weighted average common shares outstanding, basic and diluted	100,630		97,248		85,715

[1] Net loss per common share, basic and diluted, are computed independently for each quarter and the full year based upon respective average shares outstanding. Therefore, the sum of the quarterly net loss per common share amounts may not equal the annual amounts reported.