Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statements of Operations
Collaboration revenue	$ 3,448	$ 39,575	$ 46,723	$ 39,575
Operating expenses:
Research and development	40,479	17,105	97,095	66,189
General and administrative	10,412	8,812	31,955	22,731
Total operating expenses	50,891	25,917	129,050	88,920
Income (loss) from operations	(47,443)	13,658	(82,327)	(49,345)
Interest income and other	339	73	630	189
Income (loss) before income tax provision	(47,104)	13,731	(81,697)	(49,156)
Income tax (benefit) provision	(7,531)	5,179	(11,629)	35,964
Net income (loss)	$ (39,573)	$ 8,552	$ (70,068)	$ (85,120)
Net income (loss) per common share:
Basic (in dollars per share)	$ (1.14)	$ 0.26	$ (2.03)	$ (2.57)
Diluted (in dollars per share)	$ (1.14)	$ 0.25	$ (2.03)	$ (2.57)
Weighted average common shares outstanding:
Basic (in shares)	34,782	33,531	34,432	33,074
Diluted (in shares)	34,782	34,859	34,432	33,074