Nature of the Business and Operations and Liquidity - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended				7 Months Ended	51 Months Ended
	Apr. 29, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($) employee	Mar. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($) employee	Mar. 31, 2015 USD ($)
Description Of Business [Line Items]
Accumulated deficit				$ (938,539)	$ (928,184)			$ (938,539)
Cash and cash equivalents				35,211	39,330	$ 38,561		$ 35,211	$ 20,490
Net cash used in operating activities				$ 2,060		3,035
Number of workforce persons | employee				379				379
Cash flows from financing activities				$ (1,461)		$ 21,183		$ 69,500
Proceeds from additional equity offering	$ 22,300
Tres Amigas
Description Of Business [Line Items]
Minority share investment proceeds					$ 300
Scenario, Forecast | Tres Amigas
Description Of Business [Line Items]
Minority investment, percentage of investment sold							100.00%
Minority share investment proceeds			$ 300				$ 600
INOX Wind Limited
Description Of Business [Line Items]
Strategic agreements value		$ 210,000
Manufacturing agreement period, additional period required		3 years
INOX Wind Limited | Minimum
Description Of Business [Line Items]
Period allowable to manufacture the electrical control system		3 years
INOX Wind Limited | Maximum
Description Of Business [Line Items]
Period allowable to manufacture the electrical control system		4 years