Collaborative Research and Development Agreements (Details) (USD $)	12 Months Ended			1 Months Ended	6 Months Ended	0 Months Ended	1 Months Ended		3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2014	Dec. 31, 2014	Feb. 01, 2012	Sep. 30, 2012	Nov. 30, 2007	Sep. 30, 2012
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Write-off and other	$ 43,000	$ 0	$ 0
GlaxoSmithKline [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from license fees received				6,000,000	6,000,000
Revenue recognized					5,000,000
Contingent payment					14,000,000
Milestones receivable					6,500,000
Term of milestone agreement				3 years	30 months
Contingent payment upon completion of milestones and agreement					7,500,000
Minimum milestone receivable					5,750,000.00
Maximum milestone receivable					38,500,000.0
License extension acceptance period				3 years
Termination notice period				90 days
License revenue					1,000,000
Deferred revenue	5,000,000				5,000,000
Merck [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License revenue	2,000,000	1,800,000
Deferred revenue	1,100,000	700,000			1,100,000
Term of collaborative research and development agreement (in years)						5 years
Sales revenue, goods	2,500,000	1,000,000
Arch [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Sales revenue, goods	500,000	2,100,000
Write-off and other	0	400,000
Shell [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Term of collaborative research and development agreement (in years)								5 years
Amount of new shell agreement requires Shell pay							7,500,000
Collection of agreement									7,500,000
Milestone payment under Shell Research Agreement	$ 3,000,000
Liquid fuel (gallons)	30,000,000
Period of research agreement with shell (years)	10 years
Collaborative agreements exclusively right period (years)	3 years