Components of Inventory Balances (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule Of Inventory [Line Items]
Finished goods	$ 1,071	$ 192
Work in process	266	224
Spare parts	1,418	1,195
Total inventories	4,243	3,581
Corn
Schedule Of Inventory [Line Items]
Raw materials	1,182	1,456
Enzymes And Other Inputs
Schedule Of Inventory [Line Items]
Raw materials	$ 306	$ 514