Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property and equipment
Property and equipment, gross	$ 8,145,000	$ 6,499,000
Less accumulated depreciation and amortization	(5,591,000)	(5,078,000)
Property and equipment, net	2,554,000	1,421,000
Depreciation expense	512,000	642,000	650,000
Computer equipment
Property and equipment
Property and equipment, gross	798,000	615,000
Software
Property and equipment
Property and equipment, gross	209,000	209,000
Lab equipment and furniture
Property and equipment
Property and equipment, gross	4,809,000	3,896,000
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 2,329,000	$ 1,779,000