Collaborative Research and Development Agreements, Government Programs and Licenses - Additional Information (Detail) (USD $)	1 Months Ended			1 Months Ended			1 Months Ended	3 Months Ended				1 Months Ended	3 Months Ended				3 Months Ended
	Nov. 30, 2011 gal	Mar. 31, 2013	Dec. 31, 2012	Jan. 31, 2013 Archer Daniels Midland Company	Nov. 30, 2012 Collaboration Agreement T	Feb. 28, 2013 Mitsui & Co., Ltd	Sep. 30, 2011 Department of defense Phase 1 gal	Mar. 31, 2013 Department of defense Phase 1	Mar. 31, 2012 Department of defense Phase 1	Dec. 31, 2012 Department of defense Phase 1	Sep. 30, 2010 Department of defense Phase 1	Aug. 31, 2011 Department of defense Phase 2 gal	Mar. 31, 2013 Department of defense Phase 2	Mar. 31, 2012 Department of defense Phase 2	Dec. 31, 2012 Department of defense Phase 2	Sep. 30, 2010 Department of defense Phase 2	Mar. 31, 2013 Department of energy	Mar. 31, 2012 Department of energy	Dec. 31, 2012 Department of energy	Dec. 31, 2009 Department of energy
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract amount						$ 20,000,000					$ 5,600,000					$ 4,600,000
Delivered diesel fuel under contract							75,000					75,000
Current DoD contract, revenues								0	0				0	14,000
Unbilled revenue		2,276,000	3,150,000					0		0			0		0		1,400,000		2,100,000
Deferred revenue balances								0		0			0		0		0		0
Funds awarded to partially fund an integrated biorefinery																				21,800,000
Company recognized revenues																	$ 7,000	$ 2,000,000
Renewable fuels	450,000
Jet fuel	100,000
Marine distillate fuel	350,000
Warrants to purchase number of common stock				500,000
Warrant vesting period				5 years
Initial production capacity per year					20,000
Initial expansion production capacity per year					40,000
Expanded production capacity per year					100,000