Balance Sheets Details (Property and Equipment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 37,070	$ 37,070		$ 37,866
Less: accumulated depreciation and amortization	(30,880)	(30,880)		(29,461)
Property and equipment, net, excluding construction in progress	6,190	6,190		8,405
Property and equipment	6,215	6,215		8,446
Less: Impairment of laboratory equipment	(1,841)	(1,841)	0	0
Property and equipment, net	4,374	4,374		8,446
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	23,069	23,069		23,949
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,517	9,517		9,493
Computer equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,257	3,257		3,196
Office equipment and furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,227	1,227		1,228
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 25	$ 25		$ 41