CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaboration revenues:
Product revenue	$ 66,803	$ 74,648	$ 48,503
Research and development revenue	72,079	34,971	41,147
Total collaboration revenue	138,882	109,619	89,650
Operating expenses:
Research and development	149,226	119,880	126,033
General and administrative	82,207	64,466	48,051
Total operating expenses	231,433	184,346	174,084
Operating loss	(92,551)	(74,727)	(84,434)
Other income:
Interest income	4,427	2,226	808
Other income, net	28	51,498	313
Total other income	4,455	53,724	1,121
Net loss	$ (88,096)	$ (21,003)	$ (83,313)
Net loss per share:
Basic and diluted (in dollars per share)	$ (1.20)	$ (0.31)	$ (1.32)
Weighted average shares outstanding:
Basic and diluted (in shares)	73,136	68,656	63,130
Comprehensive loss:
Net loss	$ (88,096)	$ (21,003)	$ (83,313)
Net unrealized holding (losses) gains on available-for-sale marketable securities	(226)	82	20
Comprehensive loss	$ (88,322)	$ (20,921)	$ (83,293)