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Summary of Significant Accounting Policies - Additional Information (Detail) ft² in Thousands, $ in Millions |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Apr. 04, 2017 | Dec. 31, 2015 USD ($) | Mar. 31, 2017 USD ($) shares | Mar. 31, 2016 USD ($) shares | Mar. 31, 2015 USD ($) shares | Apr. 03, 2017 ft²
Payments received from customers |  |  | $ 0.9 |  |  |
Guaranteed annual payments, description |  |  | BASF has also agreed to make guaranteed annual payments to the Company through fiscal 2017 and has an option to continue the joint development through fiscal 2018. |  |  |
Repatriated amount |  |  | $ 2.1 |  |  |
Common equivalent shares not included in the calculation of diluted EPS (in shares) | shares |  |  | 1,538,418 | 1,552,959 | 1,567,352 |
Net foreign currency transaction and hedging gains (losses) |  |  | $ 0.1 | $ (2.3) | $ 2.8 |
Foreign earnings repatriated |  |  |  |  |  |
Federal and state deferred tax liability |  |  | $ 0.7 |  |  |
Tres Amigas |  |  |  |  |  |
Impairment of minority interest investments |  |  |  | 0.7 |  |
Blade Dynamics Ltd |  |  |  |  |  |
Impairment of minority interest investments |  |  |  |  | $ 3.5 |
Maximum |  |  |  |  |  |
Warranty period |  |  | 3 years |  |  |
Minimum |  |  |  |  |  |
Warranty period |  |  | 1 year |  |  |
Inox Wind Limited |  |  |  |  |  |
Strategic agreements value |  | $ 210.0 |  |  |  |
Inox Wind Limited | Maximum |  |  |  |  |  |
Period allowable to manufacture the electrical control system |  | 4 years |  |  |  |
Inox Wind Limited | Minimum |  |  |  |  |  |
Period allowable to manufacture the electrical control system |  | 3 years |  |  |  |
BASF Corporation |  |  |  |  |  |
License revenue |  |  |  | $ 3.0 |  |
Credit concentration risk | Accounts receivable | Inox Wind Limited | Maximum |  |  |  |  |  |
Risk percentage |  |  | 52.00% | 84.00% |  |
Credit concentration risk | Accounts receivable | Scottish and Southern Energy | Maximum |  |  |  |  |  |
Risk percentage |  |  | 17.00% |  |  |
Subsequent event |  |  |  |  |  |
Number of positions eliminated, period percent | 8.00% |  |  |  |  |
Subsequent event | Manufacturing facility |  |  |  |  |  |
Area of facility (in sq ft) | ft² |  |  |  |  |  | 355

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