Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Research and development milestones [Member]	Aug. 31, 2013 Maximum [Member]	Sep. 30, 2014 BioHelix [Member]	Mar. 31, 2014 BioHelix [Member]	Dec. 31, 2013 BioHelix [Member]	May 31, 2013 BioHelix [Member] Minimum [Member]	May 31, 2013 BioHelix [Member] Maximum [Member]	Sep. 30, 2014 Claims and litigation [Member]	Dec. 31, 2013 Claims and litigation [Member]	Sep. 30, 2014 Research and Development Agreements [Member]	Dec. 31, 2013 Research and Development Agreements [Member]
Sale Leaseback Transaction [Line Items]
Accrued in other current liabilities	$ 8,444,000		$ 8,444,000		$ 5,611,000								$ 300,000	$ 300,000
Company had royalty and license expenses relating to those agreements	100,000	200,000	600,000	700,000
Current commitments															3,900,000	2,300,000
Contingent consideration	300,000		300,000			4,000,000	700,000				5,000,000	13,000,000
Payment of contingent consideration			2,112,000					1,000,000	1,100,000	900,000
Current portion of contingent consideration	619,000		619,000		1,493,000			600,000
Contingent consideration non-current portion	6,100,000		6,100,000		7,315,000			5,800,000
Milestone payments paid						$ 900,000