CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Total revenues	$ 13,281,000	$ 10,928,000	$ 37,407,000	$ 40,030,000
Operating expenses:
Research and development	21,015,000	47,243,000	88,467,000	130,775,000
General and administrative	9,208,000	8,347,000	28,686,000	26,994,000
Restructuring charge	1,020,000	870,000	20,921,000	3,287,000
Total operating expenses	31,243,000	56,460,000	138,074,000	161,056,000
Loss from operations	(17,962,000)	(45,532,000)	(100,667,000)	(121,026,000)
Investment income, net	1,032,000	1,369,000	3,741,000	2,845,000
Non-cash interest expense on liability related to the sale of future royalties and convertible senior notes	(4,275,000)	(2,546,000)	(11,525,000)	(8,203,000)
Interest expense on convertible senior notes	(24,000)	(23,000)	(71,000)	(70,000)
Other expense, net	(521,000)	(75,000)	(425,000)	(590,000)
Net loss	$ (21,750,000)	$ (46,807,000)	$ (108,947,000)	$ (127,044,000)
Basic and diluted net loss per common share (in dollar per share)	$ (0.15)	$ (0.32)	$ (0.74)	$ (0.92)
Basic and diluted weighted average common shares outstanding (in shares)	148,479	147,220	148,143	137,472
Total comprehensive loss	$ (21,750,000)	$ (46,807,000)	$ (108,947,000)	$ (127,044,000)
License and milestone fees
Revenues:
Total revenues	79,000	672,000	5,237,000	13,533,000
Non-cash royalty revenue related to the sale of future royalties
Revenues:
Total revenues	$ 13,202,000	8,441,000	32,102,000	22,873,000
Research and development support
Revenues:
Total revenues		388,000	$ 68,000	1,159,000
Clinical materials revenue
Revenues:
Total revenues		$ 1,427,000		$ 2,465,000