Nature of the Business and Operations and Liquidity - Additional Information (Detail) Share data in Millions, except Per Share data, unless otherwise specified	6 Months Ended					0 Months Ended			3 Months Ended
	Sep. 30, 2014 USD ($) Employee	Sep. 30, 2013 USD ($)	Mar. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)	Nov. 15, 2013 New Term Loan USD ($)	Aug. 29, 2014 Ghodawat Energy Pvt Ltd USD ($)	Aug. 29, 2014 Ghodawat Energy Pvt Ltd EUR (€)	Jun. 05, 2012 Hercules Senior Secured Loan USD ($)	Sep. 30, 2014 MLV & Co. LLC Atm Arrangement USD ($)	Nov. 15, 2013 MLV & Co. LLC Atm Arrangement USD ($)
Description Of Business [Line Items]
Accumulated deficit	$ (895,328,000)		$ (856,389,000)
Cash and cash equivalents	34,679,000	25,867,000	43,114,000	39,243,000
Net cash used in operating activities	11,369,000	14,779,000
Liability for damages						10,600,000	8,300,000
Interest rate accrued on liability for damage						5.33%	5.33%
Number of workforce persons	291
Debt, face amount					10,000,000			10,000,000
Common stock										30,000,000
Net proceeds from sale of common stock									3,700,000
Sale of common stock									2.1
Average sale price of share									$ 1.75
Common Stock, Value, Outstanding									$ 17,100,000