Collaborative Research and Development Agreements, Government Programs and Licenses - Additional Information (Detail)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2013 shares	Sep. 30, 2015 USD ($) T $ / shares	Sep. 30, 2014 USD ($) $ / shares	Sep. 30, 2015 USD ($) T $ / shares shares	Sep. 30, 2014 USD ($) $ / shares	Apr. 02, 2014 $ / shares	Feb. 28, 2013 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Rent expense related to lease		$ 3,000,000	$ 2,600,000	$ 8,700,000	$ 7,900,000
Average volatility (percent)				78.00%	54.00%
Average risk-free interest rate (percent)				1.31%	1.63%
Exercise price (in dollars per share) | $ / shares		$ 7.17	$ 7.17	$ 7.17	$ 7.17
Share price (in dollars per share) | $ / shares		$ 2.77	$ 10.98	$ 2.77	$ 10.98	$ 11.00
Average expected remaining life				3 years 8 months 19 days	4 years 8 months 19 days
Archer Daniels Midland Extension Warrant
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Warrant vesting period	5 years
Additional warrants to be granted under extension of contract | shares	500,000
Unilever
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Minimum supply commitment of oil | T		10,000		10,000
Bunge Ltd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized under joint development agreement				$ 2,000,000
Archer-Daniels-Midland Company
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Warrants to purchase number of common stock | shares	500,000
Warrant vesting period	5 years
Rent expense related to lease		$ 21,000	$ 100,000	$ 72,000	$ 500,000
Warrant shares vested | shares				191,666
Mitsui & Co., Ltd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract amount							$ 20,000,000.0
Revenue recognized under joint development agreement		$ 0	$ 0	$ 2,100,000	$ 1,500,000