Condensed Consolidated Statements of Loss and Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Collaboration revenue	$ 364	$ 1,978	$ 2,461	$ 46,236
Product sales	93	188	1,646	294
Total revenue	457	2,166	4,107	46,530
Operating expenses:
Cost of goods sold	3,279	3,951	11,973	6,912
Research and development	3,391	5,457	10,553	16,475
General and administrative	3,827	3,097	11,773	12,016
Total operating expenses	10,497	12,505	34,299	35,403
Loss from operations	(10,040)	(10,339)	(30,192)	11,127
(Loss)/gain on change in fair value of contingent consideration liability	(1,100)	(1,613)	5,349	(44,013)
Interest and other income/ (expense), net	14	1	22	18
Interest expense	(2,202)	(461)	(5,204)	(1,055)
Net loss	(13,328)	(12,412)	(30,025)	(33,923)
Basic and diluted net loss per share	$ (0.77)	$ (0.72)	$ (1.73)	$ (2.06)
Shares used to compute basic and diluted net loss per share	17,371	17,238	17,328	16,467
Other Comprehensive Loss
Change in unrealized gain/(loss) on marketable securities	(3)	(3)	(2)	2
Comprehensive loss	$ (13,331)	$ (12,415)	$ (30,027)	$ (33,921)