Identifiable Assets by Reporting Segment (Detail) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Segment Reporting Disclosure [Line Items]
Total assets	$ 58,401,406	$ 61,261,360
Fuel Storage & Vehicle Systems
Segment Reporting Disclosure [Line Items]
Total assets	24,244,419	22,488,400
Renewable Energy - Held for Sale
Segment Reporting Disclosure [Line Items]
Total assets	31,108,058	34,226,458
Corporate
Segment Reporting Disclosure [Line Items]
Total assets	$ 3,048,929	$ 4,546,502