CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Collaboration revenues:
Product revenue	$ 4,774	$ 2,579	$ 11,798	$ 43,960
Research and development revenue	5,977	2,523	10,918	7,233
Total collaboration revenue	10,751	5,102	22,716	51,193
Operating expenses:
Research and development	27,435	20,233	71,771	58,805
General and administrative	8,977	10,999	30,202	34,309
Total operating expenses	36,412	31,232	101,973	93,114
Operating loss	(25,661)	(26,130)	(79,257)	(41,921)
Other income:
Interest income	224	308	736	950
Other income	55		174
Total other income	279	308	910	950
Net loss	(25,382)	(25,822)	(78,347)	(40,971)
Basic and diluted net loss per share (in dollar per share)	$ (0.50)	$ (0.51)	$ (1.54)	$ (0.81)
Weighted average shares used in computing basic and diluted net loss per share (in shares)	51,055	50,500	50,813	50,365
Comprehensive loss:
Net loss	(25,382)	(25,822)	(78,347)	(40,971)
Net unrealized holding gains on available-for-sale marketable securities	98	185	9	252
Comprehensive loss	$ (25,284)	$ (25,637)	$ (78,338)	$ (40,719)