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Business Segments - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment MW	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable business segments | segment			2
Stock-based compensation expense	$ 478	$ 653	$ 1,232	$ 1,653
Restructuring charges	(12)	0	1,328	0
Change in fair value of contingent consideration	201	0	$ 201	0
Minimum
Segment Reporting Information [Line Items]
Megawatts of drive trains and power ratings | MW			2
Unallocated corporate expenses
Segment Reporting Information [Line Items]
Stock-based compensation expense	$ 500	$ 700	$ 1,200	$ 1,700
Restructuring charges			$ 1,300

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Power of wind turbines.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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