Nature of the Business and Operations and Liquidity - Additional Information (Detail) $ in Thousands			1 Months Ended	3 Months Ended		63 Months Ended
	May 26, 2017 USD ($)	May 10, 2017 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2017 USD ($) employee	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) employee	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Description Of Business [Line Items]
Accumulated deficit				$ (970,809)		$ (970,809)	$ (955,557)
Cash and cash equivalents				37,477	$ 35,211	$ 37,477	$ 26,784	$ 39,330
Net cash used in operating activities				5,430	2,060
Restructuring charges				$ 1,339	0
Number of workforce persons | employee				326		326
Cash flows from financing activities				$ 15,105	$ (1,461)	$ 85,000
Proceeds from additional equity offering	$ 17,000	$ 17,000
INOX Wind Limited
Description Of Business [Line Items]
Strategic agreements value			$ 210,000
Manufacturing agreement period, additional period required			3 years