American Superconductor (AMSC) 10-Q 2 Nov 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Sep. 30, 2016	Oct. 28, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Entity Registrant Name	AMERICAN SUPERCONDUCTOR CORP /DE/
Trading Symbol	AMSC
Entity Central Index Key	880,807
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		14,199,202

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Current assets:
Cash and cash equivalents	$ 25,262	$ 39,330
Accounts receivable, net	12,130	19,264
Inventory	26,448	18,512
Prepaid expenses and other current assets	2,847	5,778
Restricted cash	452	457
Total current assets	67,139	83,341
Property, plant and equipment, net	46,677	49,778
Intangibles, net	571	854
Restricted cash	934	934
Deferred tax assets	96	96
Other assets	336	315
Total assets	115,753	135,318
Current liabilities:
Accounts payable and accrued expenses	18,581	23,156
Note payable, current portion, net of discount of $77 as of September 30, 2016 and $42 as of March 31, 2016	2,089	2,624
Derivative liabilities	2,660	3,227
Deferred revenue	17,341	12,000
Total current liabilities	40,671	41,007
Note payable, net of discount of $133 as of March 31, 2016	0	1,367
Deferred revenue	8,262	9,269
Deferred tax liabilities	63	63
Other liabilities	54	63
Total liabilities	49,050	51,769
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock	143	141
Additional paid-in capital	1,013,676	1,011,813
Treasury stock	(1,371)	(881)
Accumulated other comprehensive income	119	660
Accumulated deficit	(945,864)	(928,184)
Total stockholders' equity	66,703	83,549
Total liabilities and stockholders' equity	$ 115,753	$ 135,318

Unaudited Condensed Consolidat3

Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Statement of Financial Position [Abstract]
Note payable, unamortized discount, current	$ 77	$ 42
Note payable, unamortized discount, noncurrent	$ 0	$ 133

Unaudited Condensed Consolidat4

Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenues	$ 18,507	$ 19,004	$ 31,852	$ 42,727
Cost of revenues	16,404	15,992	28,886	36,495
Gross profit	2,103	3,012	2,966	6,232
Operating expenses:
Research and development	2,867	3,003	5,819	6,165
Selling, general and administrative	6,347	6,773	13,563	14,308
Impairment of minority interest investment	0	38	0	779
Amortization of acquisition related intangibles	39	39	78	78
Total operating expenses	9,253	9,853	19,460	21,330
Operating loss	(7,150)	(6,841)	(16,494)	(15,098)
Change in fair value of derivatives and warrants	1,244	701	567	1,501
Interest expense, net	(107)	(286)	(243)	(603)
Other expense, net	(518)	(397)	(393)	(1,169)
Loss before income tax expense	(6,531)	(6,823)	(16,563)	(15,369)
Income tax expense	794	875	1,117	1,450
Net loss	$ (7,325)	$ (7,698)	$ (17,680)	$ (16,819)
Net loss per common share
Basic (in dollars per share)	$ (0.53)	$ (0.57)	$ (1.29)	$ (1.31)
Diluted (in dollars per share)	$ (0.53)	$ (0.57)	$ (1.29)	$ (1.31)
Weighted average number of common shares outstanding
Basic (in shares)	13,769	13,595	13,723	12,808
Diluted (in shares)	13,769	13,595	13,723	12,808

Unaudited Condensed Consolidat5

Unaudited Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (7,325)	$ (7,698)	$ (17,680)	$ (16,819)
Other comprehensive gain (loss), net of tax:
Foreign currency translation gains (losses)	111	(111)	(541)	319
Total other comprehensive gain (loss), net of tax	111	(111)	(541)	319
Comprehensive loss	$ (7,214)	$ (7,809)	$ (18,221)	$ (16,500)

Unaudited Condensed Consolidat6

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (17,680)	$ (16,819)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation and amortization	3,735	4,009
Stock-based compensation expense	1,653	1,834
Impairment of minority interest investments	0	746
Provision for excess and obsolete inventory	671	829
Write-off prepaid taxes	0	511
Loss from minority interest investments	0	356
Change in fair value of derivatives and warrants	(567)	(1,501)
Non-cash interest expense	98	207
Other non-cash items	(103)	921
Changes in operating asset and liability accounts:
Accounts receivable	7,118	(1,196)
Inventory	(8,696)	3,478
Prepaid expenses and other current assets	2,843	2,957
Accounts payable and accrued expenses	(4,481)	(3,337)
Deferred revenue	4,497	(762)
Net cash used in operating activities	(10,912)	(7,767)
Cash flows from investing activities:
Purchase of property, plant and equipment	(359)	(310)
Proceeds from the sale of property, plant and equipment	15	7
Change in restricted cash	4	(16)
Change in other assets	(28)	91
Net cash used in investing activities	(368)	(228)
Cash flows from financing activities:
Employee taxes paid related to net settlement of equity awards	(490)	(109)
Repayment of debt	(2,000)	(2,000)
Proceeds from public equity offering, net	0	22,281
Proceeds from exercise of employee stock options and ESPP	0	30
Net cash (used in)/provided by financing activities	(2,490)	20,202
Effect of exchange rate changes on cash and cash equivalents	(298)	(125)
Net (decrease)/increase in cash and cash equivalents	(14,068)	12,082
Cash and cash equivalents at beginning of year	39,330	20,490
Cash and cash equivalents at end of year	25,262	32,572
Supplemental schedule of cash flow information:
Cash paid for income taxes, net of refunds	894	758
Issuance of common stock to settle liabilities	212	197
Cash paid for interest	$ 187	$ 391

Nature of the Business and Oper

Nature of the Business and Operations and Liquidity	6 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Operations and Liquidity	Nature of the Business and Operations and Liquidity Nature of the Business and Operations American Superconductor Corporation (“AMSC” or the “Company”) was founded on April 9, 1987. The Company is a leading provider of megawatt-scale solutions that lower the cost of wind power and enhance the performance of the power grid. In the wind power market, the Company enables manufacturers to field wind turbines through its advanced engineering, support services and power electronics products. In the power grid market, the Company enables electric utilities and renewable energy project developers to connect, transmit and distribute power through its transmission planning services and power electronics and superconductor-based products. The Company’s wind and power grid products and services provide exceptional reliability, security, efficiency and affordability to its customers. These unaudited condensed consolidated financial statements of the Company have been prepared on a going concern basis in accordance with United States generally accepted accounting principles (“GAAP”) and the Securities and Exchange Commission’s (“SEC”) instructions to Form 10-Q. The going concern basis of presentation assumes that the Company will continue operations and will be able to realize its assets and discharge its liabilities and commitments in the normal course of business. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those instructions. The year-end condensed balance sheet data was derived from audited financial statements but does not include all disclosures required by GAAP. The unaudited condensed consolidated financial statements, in the opinion of management, reflect all adjustments (consisting of normal recurring adjustments) necessary for a fair statement of the results for the interim periods ended September 30, 2016 and 2015 and the financial position at September 30, 2016 . Liquidity The Company has experienced recurring operating losses and as of September 30, 2016 , the Company had an accumulated deficit of $945.9 million . In addition, the Company has experienced recurring negative operating cash flows. At September 30, 2016 , the Company had cash and cash equivalents of $25.3 million . Cash used in operations for the six months ended September 30, 2016 was $10.9 million . From April 1, 2011 through the date of this filing, the Company has reduced its global workforce substantially. The Company has taken actions to consolidate certain business operations to reduce facility costs. As of September 30, 2016 , the Company had a global workforce of 366 persons. The Company plans to closely monitor its expenses and, if required, expects to further reduce operating costs and capital spending to enhance liquidity. Over the last several years, the Company has entered into several debt and equity financing arrangements in order to enhance liquidity. Since April 1, 2012, the Company has generated aggregate cash flows from financing activities of $68.5 million . This amount includes proceeds from an April 2015 equity offering, which generated net proceeds of approximately $22.3 million , after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. See Note 9, “Debt”, and Note 11 “Stockholders Equity” for further discussion of these financing arrangements. The Company believes that it is in compliance with the covenants and restrictions included in the agreements governing its debt arrangements as of September 30, 2016 . In December 2015, the Company entered into a set of strategic agreements valued at approximately $210.0 million with Inox Wind Ltd. (“Inox”), which includes a multi-year supply contract pursuant to which the Company will supply electric control systems to Inox and a license agreement allowing Inox to manufacture a limited number of electrical control systems over the next three to four years. After this initial three to four year period, Inox agreed that the Company will continue as Inox’s preferred supplier and Inox will be required to purchase from the Company a majority of its electric control systems requirements for an additional three -year period. These agreements are expected to provide a foundation for the business as the Company pursues its longer-term objectives. On March 11, 2016, the Company sold 100% of its minority share investment in Tres Amigas LLC ("Tres Amigas") to an investor for $0.6 million . The Company received $0.3 million according to the terms of the purchase agreement upon closing, which was recorded as a gain during the three months ended March 31, 2016. The final $0.3 million is to be paid when Tres Amigas achieves the earlier of certain agreed-upon financing conditions, which is expected to occur during the third quarter of fiscal 2016. See Note 13, “Minority Investments”, for further information about such investment. The Company believes it has sufficient liquidity to fund its operations, capital expenditures and scheduled cash payments under its debt obligations for the next twelve months. The Company’s liquidity is highly dependent on its ability to increase revenues, its ability to control its operating costs, its ability to maintain compliance with the covenants and restrictions on its debt obligations (or obtain waivers from its lender in the event of non-compliance), and its ability to raise additional capital, if necessary. There can be no assurance that the Company will be able to continue to raise additional capital from other sources or execute on any other means of improving liquidity described above.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company accounts for its stock-based compensation at fair value. The following table summarizes stock-based compensation expense by financial statement line item for the three and six months ended September 30, 2016 and 2015 (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Cost of revenues $ 49 $ 61 $ 99 $ 158 Research and development 62 87 92 283 Selling, general and administrative 542 558 1,462 1,393 Total $ 653 $ 706 $ 1,653 $ 1,834 The Company granted 9,703 stock options and 161,000 restricted stock awards during the six months ended September 30, 2016 , and 392,689 restricted stock awards during the six months ended September 30, 2015 . These awards generally vest over 2- 3 years . Awards for restricted stock include both time-based and performance-based awards. For options and awards that vest upon the passage of time, expense is being recorded over the vesting period. Performance-based awards are expensed over the requisite service period based on probability of achievement. The estimated fair value of the Company’s stock-based awards, less expected annual forfeitures, is amortized over the awards’ service period. The total unrecognized compensation cost for unvested outstanding stock options was $0.5 million at September 30, 2016 . This expense will be recognized over a weighted average expense period of approximately 2.4 years . The total unrecognized compensation cost for unvested outstanding restricted stock was $2.8 million at September 30, 2016 . This expense will be recognized over a weighted-average expense period of approximately 1.8 years . The Company granted 9,703 stock options during the three and six months ended September 30, 2016 and did not grant any stock options in the three or six months ended September 30, 2015 . These options will vest over 2 years. The weighted average assumptions used in the Black Scholes valuation model for stock options granted during the six months ended September 30, 2016 are as follows: Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Expected volatility 67.6 % N/A 67.6 % N/A Risk-free interest rate 1.3 % N/A 1.3 % N/A Expected life (years) 5.7 N/A 5.7 N/A Dividend yield None N/A None N/A The expected volatility rate was estimated based on an equal weighting of the historical volatility of the Company's common stock and the implied volatility of the Company's traded options. The expected term was estimated based on an analysis of the Company's historical experience of exercise, cancellation and expiration patterns. The risk-free interest rate is based on the average of the five- and seven-year U.S. Treasury rates.

Computation of Net Loss per Com

Computation of Net Loss per Common Share	6 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Computation of Net Loss per Common Share	Computation of Net Loss per Common Share Basic net loss per share (“EPS”) is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. Where applicable, diluted EPS is computed by dividing the net loss by the weighted-average number of common shares and dilutive common equivalent shares outstanding during the period, calculated using the treasury stock method. Common equivalent shares include the effect of restricted stock, exercise of stock options and warrants and contingently issuable shares. For each of the three and six months ended September 30, 2016 and 2015 , 1.6 million shares were not included in the calculation of diluted EPS as they were considered anti-dilutive, of which 0.4 million relate to outstanding stock options, and 1.2 million relate to outstanding warrants, respectively. The following table reconciles the numerators and denominators of the earnings per share calculation for the three and six months ended September 30, 2016 and 2015 (in thousands, except per share data): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Numerator: Net loss (7,325 ) (7,698 ) $ (17,680 ) $ (16,819 ) Denominator: Weighted-average shares of common stock outstanding 14,190 14,054 14,161 12,958 Weighted-average shares subject to repurchase (421 ) (459 ) (438 ) (150 ) Shares used in per-share calculation ― basic 13,769 13,595 13,723 12,808 Shares used in per-share calculation ― diluted 13,769 13,595 13,723 12,808 Net loss per share ― basic (0.53 ) (0.57 ) $ (1.29 ) $ (1.31 ) Net loss per share ― diluted (0.53 ) (0.57 ) $ (1.29 ) $ (1.31 )

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements A valuation hierarchy for disclosure of the inputs to valuation used to measure fair value has been established. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1 - Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 - Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). Level 3 - Unobservable inputs that reflect the Company’s assumptions that market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available, including its own data. The Company provides a gross presentation of activity within Level 3 measurement roll-forward and details of transfers in and out of Level 1 and 2 measurements. A change in the hierarchy of an investment from its current level is reflected in the period during which the pricing methodology of such investment changes. Disclosure of the transfer of securities from Level 1 to Level 2 or Level 3 is made in the event that the related security is significant to total cash and investments. The Company did not have any transfers of assets and liabilities from Level 1 and Level 2 to Level 3 of the fair value measurement hierarchy during the three and six months ended September 30, 2016 . A financial asset’s or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following table provides the assets and liabilities carried at fair value on a recurring basis, measured as of September 30, 2016 and March 31, 2016 (in thousands): Total Carrying Value Quoted Prices in Active Markets ( Level 1) Significant Other Observable Inputs ( Level 2) Significant Unobservable Inputs ( Level 3) September 30, 2016: Assets: Cash equivalents $ 14,077 $ 14,077 $ — $ — Derivative liabilities: Warrants $ 2,660 $ — $ — $ 2,660 Total Quoted Prices in Significant Other Significant March 31, 2016: Assets: Cash equivalents $ 16,040 $ 16,040 $ — $ — Derivative liabilities: Warrants $ 3,227 $ — $ — $ 3,227 The table below reflects the activity for the Company’s major classes of liabilities measured at fair value on a recurring basis (in thousands): Warrants April 1, 2016 $ 3,227 Mark to market adjustment (567 ) Balance at September 30, 2016 $ 2,660 Warrants April 1, 2015 $ 2,999 Mark to market adjustment 228 Balance at March 31, 2016 $ 3,227 Valuation Techniques Cash Equivalents Cash equivalents consist of highly liquid instruments with maturities of three months or less that are regarded as high quality, low risk investments and are measured using such inputs as quoted prices, and are classified within Level 1 of the valuation hierarchy. Cash equivalents consist principally of certificates of deposits and money market accounts. Warrants Warrants were issued in conjunction with a Securities Purchase Agreement (the “Purchase Agreement”) with Capital Ventures International (“CVI”) in April 2012, an equity offering to Hudson Bay Capital in November 2014, and a Loan and Security Agreement with Hercules Technology Growth Capital, Inc. (“Hercules”) in June 2012 and through subsequent amendments. See Note 9, “Debt,” and Note 10 “Warrants and Derivative Liabilities,” for additional information. These warrants are subject to revaluation at each balance sheet date, and any change in fair value will be recorded as a change in fair value in derivatives and warrants until the earlier of their exercise or expiration. The Company relies on various assumptions in a lattice model to determine the fair value of warrants. The Company has valued the warrants within Level 3 of the valuation hierarchy. See Note 10, “Warrants and Derivative Liabilities,” for a discussion of the warrants and the valuation assumptions used.

Accounts Receivable

Accounts Receivable	6 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Accounts receivable (billed) $ 11,417 $ 18,089 Accounts receivable (unbilled) 767 1,229 Less: Allowance for doubtful accounts (54 ) (54 ) Accounts receivable, net $ 12,130 $ 19,264

Inventory

Inventory	6 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Raw materials $ 11,233 $ 9,665 Work-in-process 2,349 3,411 Finished goods 6,429 3,215 Deferred program costs 6,437 2,221 Net inventory $ 26,448 $ 18,512 The Company recorded inventory write-downs of $0.4 million and $0.2 million for each of the three months ended September 30, 2016 and 2015 , respectively. The Company recorded inventory write-downs of $0.7 million and $0.8 million for each of the six months ended September 30, 2016 , and 2015 , respectively. These write downs were based on evaluating its inventory on hand for excess quantities and obsolescence. Deferred program costs as of September 30, 2016 and March 31, 2016 primarily represent costs incurred on programs accounted for under contract accounting where the Company needs to complete development milestones before revenue and costs will be recognized.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	6 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Accounts Payable and Accrued Expenses	Accounts Payable and Accrued Expenses Accounts payable and accrued expenses at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Accounts payable $ 6,262 $ 5,837 Accrued inventories in-transit 1,804 1,908 Accrued other miscellaneous expenses 2,431 3,003 Accrued compensation 4,093 7,526 Income taxes payable 1,297 1,281 Accrued warranty 2,694 3,601 Total $ 18,581 $ 23,156 The Company generally provides a one to three year warranty on its products, commencing upon installation. A provision is recorded upon revenue recognition to cost of revenues for estimated warranty expense based on historical experience. Product warranty activity was as follows (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Balance at beginning of period $ 2,774 $ 3,344 $ 3,601 $ 3,934 Change in accruals for warranties during the period 316 429 417 423 Settlements during the period (396 ) (500 ) (1,324 ) (1,084 ) Balance at end of period $ 2,694 $ 3,273 $ 2,694 $ 3,273

Income Taxes

Income Taxes	6 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes T he Company recorded income tax expense of $0.8 million and $1.1 million in the three and six months ended September 30, 2016 , respectively, and $0.9 million and $1.5 million in the three and six months ended September 30, 2015 , respectively. Income tax expense was primarily due to dividend withholding taxes and income taxes in the Company’s foreign jurisdictions. Accounting for income taxes requires a two-step approach to recognizing and measuring uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not the position will be sustained upon audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely to be realized upon ultimate settlement. The Company re-evaluates these uncertain tax positions on a quarterly basis. The evaluation is based on factors including, but not limited to, changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any changes in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision. The Company did not identify any uncertain tax positions in the six months ended September 30, 2016 and did not have any gross unrecognized tax benefits as of March 31, 2016.

Debt

Debt	6 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt	Debt Senior Secured Term Loans On November 15, 2013, the Company amended its existing Loan and Security Agreement with Hercules and entered into a new term loan (the “Term Loan B”), borrowing $10.0 million . After closing fees and expenses, the net proceeds to the Company for the Term Loan B were $9.8 million . The Term Loan B bears an interest rate of 11% plus the percentage, if any, by which the prime rate as reported by the Wall Street Journal exceeds 3.75% . The Company is repaying the Term Loan B in equal monthly installments ending on November 1, 2016. The principal balance of the Term Loan B is approximately $0.7 million as of September 30, 2016 . The Company will pay an end of term fee of $0.5 million upon the earlier of maturity or prepayment of the Term Loan B. The Company has accrued the end of term fee and recorded a corresponding amount into the debt discount. The Term Loan B includes a mandatory prepayment feature which allows Hercules the right to use any of the Company’s net proceeds from specified asset dispositions greater than $1.0 million in a calendar year to pay off any outstanding accrued interest and principal balance on the Term Loan B. The Company determined the fair value to be de-minimis for this feature. In addition, the Company incurred $0.2 million of legal and origination costs at inception of the loan, which have been recorded as a debt discount. On December 19, 2014, the Company entered into a second amendment with Hercules (the “Hercules Second Amendment”) and entered into a new term loan, borrowing an additional $1.5 million (the “Term Loan C”). After closing fees and expenses, the net proceeds to the Company for the Term Loan C were $1.4 million . The Term Loan B and Term Loan C are collectively referred to as the “Term Loans”. The Term Loan C also bears the same interest rate as the Term Loan B. The Company will make interest only payments until maturity on June 1, 2017 , when the loan is scheduled to be repaid in its entirety. The maturity date of the Term Loan C was extended from March 1, 2017 to June 1, 2017 due to the Company’s April 2015 equity offering which raised more than $10 million in new capital before December 31, 2015. The Company will pay an end of term fee of approximately $0.1 million upon earlier of maturity or prepayment of the Term Loan C. The Company has accrued the end of term fee and recorded a corresponding amount in the debt discount. The Term Loan C includes the same mandatory prepayment feature as the Term Loan B. The Company determined the fair value to be de-minimus for this feature. In addition, the Company incurred approximately $0.1 million of legal and origination costs at inception of the loan, which have been recorded as a debt discount. Hercules received warrants to purchase 13,927 shares of common stock (the “First Warrant”) and 25,641 shares of common stock (the “Second Warrant”) in conjunction with a prior term loan which has been repaid in full and the Term Loan B. Due to certain adjustment provisions within the warrants, they qualified for liability accounting. The fair value of the warrants, $0.4 million and $0.2 million , respectively, was recorded upon issuance to debt discount and a warrant liability. In conjunction with the Hercules Second Amendment, the First Warrant and Second Warrant were cancelled and replaced with the issuance of a new warrant (the “Hercules Warrant”) to purchase 58,823 shares of common stock at an exercise price of $11.00 per share, subject to adjustment. The Hercules Warrant expires on June 30, 2020. See Note 10, “Warrants and Derivative Liabilities”, for a discussion on the Hercules Warrant and the valuation assumptions used. Under Term Loan B, the total debt discount including the Hercules Warrant, end of term fee and legal and origination costs of $1.0 million is being amortized into interest expense over the term of the Term Loan B using the effective interest method. During both the three and six months ended September 30, 2016 the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan B of less than $0.1 million . During both the three and six months ended September 30, 2015 the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan B of $0.1 million Under Term Loan C, the total debt discount, including the Hercules Warrant, end of term fee and legal and origination costs of $0.3 million is being amortized into interest expense over the term of the Term Loan C using the effective interest method. During both the three and six months ended September 30, 2016 the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan C of less than $0.1 million . During both the three and six months ended September 30, 2015 the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan C of less than $0.1 million . The Term Loans are secured by substantially all of the Company’s existing and future assets, including a mortgage on real property owned by the Company’s wholly-owned subsidiary, ASC Devens LLC, and located at 64 Jackson Road, Devens, Massachusetts. The Term Loans contain certain covenants that restrict the Company’s ability to, among other things, incur or assume certain debt, merge or consolidate, materially change the nature of the Company’s business, make certain investments, acquire or dispose of certain assets, make guarantees or grant liens on its assets, make certain loans, advances or investments, declare dividends or make distributions or enter into transactions with affiliates. In addition, there is a covenant that requires the Company to maintain a minimum unrestricted cash balance (the “Minimum Threshold”) in the United States. As a result of the Company’s April 2015 equity offering, the Minimum Threshold was reduced to the lesser of $2.0 million or the aggregate outstanding principal balance of the Term Loans. As of September 30, 2016 , the Minimum Threshold was $2.0 million . The events of default under the Term Loans include, but are not limited to, failure to pay amounts due, breaches of covenants, bankruptcy events, cross defaults under other material indebtedness and the occurrence of a material adverse effect and/or change in control. In the case of a continuing event of default, Hercules may, among other remedies, declare due all unpaid principal amounts outstanding and any accrued but unpaid interest and foreclose on all collateral granted to Hercules as security under the Term Loans. Interest expense on the Term Loans for the three months ended September 30, 2016 and 2015 , was $0.1 million and $0.3 million , respectively, each of which included less than $0.1 million of non-cash interest expense related to the amortization of the debt discount on the respective Term Loans. Interest expense on the Term Loans for the six months ended September 30, 2016 and 2015 , was $0.3 million and $0.6 million , respectively, each of which included $0.1 million and $0.2 million , respectively, of non-cash interest expense related to the amortization of the debt discount on the respective Term Loans Although the Company believes that it is in compliance with the covenants and restrictions under the Term Loans as of September 30, 2016 , there can be no assurance that the Company will continue to be in compliance.

Warrants and Derivative Liabili

Warrants and Derivative Liabilities	6 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Warrants and Derivative Liabilities	Warrants and Derivative Liabilities Senior Convertible Note Warrant On April 4, 2012, the Company entered into the Purchase Agreement with CVI. The Purchase Agreement included a warrant to purchase 309,406 shares of the Company’s common stock (the “Original Warrant”). Pursuant to an exchange in October 2013, the Original Warrant was exchanged for a new warrant (the “Exchanged Warrant”). The Exchanged Warrant is exercisable at any time on or after the date that is six months after the issuance of the Original Warrant and entitles CVI to purchase shares of the Company’s common stock for a period of five years from the date the Original Warrant becomes exercisable at an exercise price equal to $15.94 per share, subject to certain price-based and other anti-dilution adjustments. The Exchanged Warrant may not be exercised if, after giving effect to the conversion, CVI together with its affiliates, would beneficially own in excess of 4.99% of the Company’s common stock. This percentage may be raised to any other percentage not in excess of 9.99% at the option of CVI, upon at least 61 -days prior notice to the Company, or lowered to any other percentage, at the option of CVI, at any time. The Company calculated the fair value of the Exchanged Warrant, utilizing an integrated lattice model. The lattice model is an option pricing model that involves the construction of a binomial tree to show the different paths that the underlying asset may take over the option’s life. A lattice model can take into account expected changes in various parameters such as volatility over the life of the options, providing more accurate estimates of option prices than the Black-Scholes model. See Note 4, "Fair Value Measurements", for further discussion. The Company accounts for the Exchanged Warrant as a liability due to certain adjustment provisions within the warrant, which requires that it be recorded at fair value. The Exchanged Warrant is subject to revaluation at each balance sheet date and any change in fair value is recorded as a change in fair value of derivatives and warrants until the earlier of its expiration or its exercise at which time the warrant liability will be reclassified to equity. Following is a summary of the key assumptions used to calculate the fair value of the Exchanged Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.59% 0.48% Expected annual dividend yield — — Expected volatility 70.50% 76.30% Term (years) 1.01 1.26 Fair value $0.2 million $0.4 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 0.66% 0.96% 0.64% 0.74% 0.73% Expected annual dividend yield — — — — — Expected volatility 76.76% 76.68% 73.39% 71.61% 70.42% Term (years) 1.51 1.76 2.01 2.26 2.51 Fair value $0.4 million $0.3 million $0.1 million $0.2 million $0.3 million The Company recorded net gains of $0.2 million and $0.1 million , respectively, resulting from the decrease in the fair value of the Exchanged Warrant during the three months ended September 30, 2016 and 2015 , respectively. The Company recorded net gains of $0.2 million resulting from the decrease in the fair value of the Exchanged Warrant during each of the six months ended September 30, 2016 and 2015 , respectively. Hercules Warrant On December 19, 2014, the Company entered into the Hercules Second Amendment. See Note 9, “Debt” for additional information. In conjunction with the agreement, the Company issued the Hercules Warrant to purchase 58,823 shares of the Company’s common stock. The Hercules Warrant is exercisable at any time after its issuance at an initial exercise price of $11.00 per share, subject to certain price-based and other anti-dilution adjustments, and expires on June 30, 2020 . As a result of the equity offering in April 2015, the exercise price of the Hercules Warrant was reduced to $9.41 per share. The Company accounts for the Hercules Warrant as a liability due to certain provisions within the warrant. The Hercules Warrant is subject to revaluation at each balance sheet date and any change in fair value is recorded as a change in fair value of derivatives and warrants until the earlier of its expiration or its exercise, at which time the warrant liability will be reclassified to equity. Following is a summary of the key assumptions used to calculate the fair value of the Hercules Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.97% 0.86% Expected annual dividend yield — — Expected volatility 67.98% 68.34% Term (years) 3.75 4.00 Fair value $0.2 million $0.3 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 1.08% 1.65% 1.31% 1.63% 1.41% Expected annual dividend yield — — — — — Expected volatility 70.25% 73.57% 75.32% 72.57% 74.60% Term (years) 4.25 4.50 4.75 5.00 5.25 Fair value $0.2 million $0.2 million $0.1 million $0.2 million $0.2 million The Company recorded net gains, resulting from a decrease in the fair value of the Hercules Warrant, of $0.1 million during the three months ended September 30, 2016 and less than $0.1 million during the three months ended September 30, 2015 , to change in fair value of derivatives and warrants. The Company recorded a net gain of less than $0.1 million in the fair value of the Hercules Warrant during the six months ended September 30, 2016 and a net gain of $0.1 million during the six months ended September 30, 2015 . November 2014 Warrant On November 13, 2014, the Company completed an offering of approximately 909,090 units of the Company’s common stock with Hudson Bay Capital. Each unit consisted of one share of the Company’s common stock and 0.9 of a warrant to purchase one share of common stock, or a warrant to purchase in the aggregate 818,181 shares (the “November 2014 Warrant”). The November 2014 Warrant is exercisable at any time, at an initial exercise price equal to $11.00 per share, subject to certain price-based and other anti-dilution adjustments, and expires on November 13, 2019 . As a result of the April 2015 equity offering, the exercise price of the November 2014 Warrant was reduced to $9.41 per share. The Company accounts for the November 2014 Warrant as a liability due to certain provisions within the warrant. The November 2014 Warrant is subject to revaluation at each balance sheet date and any change in fair value is recorded as a change in fair value of derivatives and warrants until the earlier of its expiration or its exercise, at which time the warrant liability will be reclassified to equity. Following is a summary of the key assumptions used to calculate the fair value of the November 2014 Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.93% 0.77% Expected annual dividend yield — — Expected volatility 68.96% 70.01% Term (years) 3.12 3.37 Fair value $2.3 million $3.2 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 0.98% 1.51% 1.17% 1.44% 1.28% Expected annual dividend yield — — — — — Expected volatility 69.88% 70.02% 73.02% 74.18% 75.96% Term (years) 3.62 3.87 4.12 4.37 4.62 Fair value $2.6 million $2.1 million $1.3 million $1.8 million $2.5 million The Company recorded net gains, resulting from a decrease in the fair value of the November 2014 Warrant, of $0.9 million and $0.5 million in the three months ended September 30, 2016 and 2015 , respectively. The Company recorded net gains of $0.3 million and $1.2 million during the six months ended September 30, 2016 and 2015 , respectively. The Company prepared its estimates for the assumptions used to determine the fair value of the warrants issued in conjunction with both the Term Loans and our unsecured, senior convertible note with CVI, as well as the November 2014 Warrant utilizing the respective terms of the warrants with similar inputs, as described above.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity On April 29, 2015, the Company completed an equity offering with Cowen and Company, LLC, under which the Company sold 4.0 million shares of its common stock at an offering price of $6.00 per share. After underwriting discounts, commissions and offering expenses, the Company received net proceeds from the offering of approximately $22.3 million .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Contingencies From time to time, the Company is involved in legal and administrative proceedings and claims of various types. The Company records a liability in its consolidated financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in a liability and the amounts of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss to the extent necessary to make the consolidated financial statements not misleading. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in its consolidated financial statements. On September 13, 2011, the Company commenced a series of legal actions in China against Sinovel Wind Group Co. Ltd. (“Sinovel”). The Company’s Chinese subsidiary, Suzhou AMSC Superconductor Co. Ltd., filed a claim for arbitration with the Beijing Arbitration Commission in accordance with the terms of the Company’s supply contracts with Sinovel. The case is captioned (2011) Jing Zhong An Zi No. 963 . The Company alleges that Sinovel committed various material breaches of its contracts with the Company and Sinovel has refused to pay past due amounts for prior shipments of core electrical components and spare parts. The Company is seeking compensation for past product shipments and retention (including interest) in the amount of approximately RMB 485 million (approximately $73 million ) due to Sinovel’s breaches of its contracts. The Company is also seeking specific performance of its existing contracts as well as reimbursement of all costs and reasonable expenses with respect to the arbitration. The value of the undelivered components under the existing contracts, including the deliveries refused by Sinovel in March 2011, amounts to approximately RMB 4.6 billion (approximately $690 million ). On October 8, 2011, Sinovel filed with the Beijing Arbitration Commission an application under the caption (2011) Jing Zhong An Zi No. 963, for a counterclaim against the Company for breach of the same contracts under which the Company filed its original arbitration claim. Sinovel claims, among other things, that the goods supplied by the Company do not conform to the standards specified in the contracts and claims damages in the amount of approximately RMB 1.2 billion (approximately $180 million ) upon Sinovel’s requests for change of counterclaim. On February 27, 2012, Sinovel filed with the Beijing Arbitration Commission an application under the caption (2012) Jing Zhong An Zi No. 157, against the Company for breach of the same contracts under which the Company filed its original arbitration claim. Sinovel claims, among other things, that the goods supplied by the Company do not conform to the standards specified in the contracts and claims damages in the amount of approximately RMB 105 million (approximately $16 million ). The Company believes that Sinovel’s claims are without merit and it intends to defend these actions vigorously. Since the proceedings in this matter are still in the early technical review phase, the Company cannot reasonably estimate possible losses or range of losses at this time. Other The Company enters into long-term construction contracts with customers that require the Company to obtain performance bonds. The Company is required to deposit an amount equivalent to some or all the face amount of the performance bonds into an escrow account until the termination of the bond. When the performance conditions are met, amounts deposited as collateral for the performance bonds are returned to the Company. In addition, the Company has various contractual arrangements in which minimum quantities of goods or services have been committed to be purchased on an annual basis. As of September 30, 2016 , the Company had $0.5 million of restricted cash included in current assets and $0.9 million of restricted cash included in long-term assets. These amounts included in restricted cash primarily represent deposits to secure letters of credit for various supply contracts. These deposits are held in interest bearing accounts.

Minority Investments

Minority Investments	6 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Minority Investments	Minority Investments Investment in Tres Amigas LLC The Company made an investment in Tres Amigas, focused on providing the first common interconnection of America’s three power grids to help the country achieve its renewable energy goals and facilitate the smooth, reliable and efficient transfer of green power from region to region. The Company’s original investment in Tres Amigas was $5.4 million . During the three months ended June 30, 2015, the Company determined that as a result of delays in Tres Amigas securing financing for the project, as well as the Company’s expectation that its investment would not be recoverable based on recent adverse market indicators for potential sales of the Company’s share of the investment, that its investment in Tres Amigas required further analysis for other-than-temporary impairment. The Company recorded an impairment charge of $0.7 million to fully impair this investment in the three months ended June 30, 2015. On March 11, 2016, the Company sold 100% of its minority share investment in Tres Amigas to an investor for $0.6 million . The Company received $0.3 million according to the terms of the purchase agreement upon closing, which was recorded as a gain during the three months ended March 31, 2016. The final $0.3 million is to be paid when Tres Amigas achieves the earlier of certain agreed-upon financing conditions which is expected to occur during the third quarter of fiscal 2016.

Business Segments

Business Segments	6 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Business Segments	Business Segments The Company reports its financial results in two reportable business segments: Wind and Grid. Through the Company’s Windtec Solutions, the Wind business segment enables manufacturers to field wind turbines with exceptional power output, reliability and affordability. The Company supplies advanced power electronics and control systems, licenses its highly engineered wind turbine designs, and provides extensive customer support services to wind turbine manufacturers. The Company’s design portfolio includes a broad range of drive trains and power ratings of 2 MWs and higher. The Company provides a broad range of power electronics and software-based control systems that are highly integrated and designed for optimized performance, efficiency, and grid compatibility. Through the Company’s Gridtec Solutions, the Grid business segment enables electric utilities and renewable energy project developers to connect, transmit and distribute power with exceptional efficiency, reliability and affordability. The sales process is enabled by transmission planning services that allow it to identify power grid congestion, poor power quality and other risks, which helps the Company determine how its solutions can improve network performance. These services often lead to sales of grid interconnection solutions for wind farms and solar power plants, power quality systems, and transmission and distribution cable systems. The Company also sells ship protection products to the U.S. Navy through its Grid business segment. The operating results for the two business segments are as follows (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Revenues : Wind $ 12,898 $ 13,583 $ 18,573 $ 31,747 Grid 5,609 5,421 13,279 10,980 Total $ 18,507 $ 19,004 $ 31,852 $ 42,727 Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Operating (loss) profit: Wind $ (1,235 ) $ (1,991 ) $ (4,264 ) $ (1,864 ) Grid (5,262 ) (4,113 ) (10,577 ) (10,621 ) Unallocated corporate expenses (653 ) (737 ) (1,653 ) (2,613 ) Total $ (7,150 ) $ (6,841 ) $ (16,494 ) $ (15,098 ) The accounting policies of the business segments are the same as those for the consolidated Company. The Company’s business segments have been determined in accordance with the Company’s internal management structure, which is organized based on operating activities. The Company evaluates performance based upon several factors, of which the primary financial measures are segment revenues and segment operating loss. The disaggregated financial results of the segments reflect allocation of certain functional expense categories consistent with the basis and manner in which Company management internally disaggregates financial information for the purpose of assisting in making internal operating decisions. In addition, certain corporate expenses which the Company does not believe are specifically attributable or allocable to either of the two business segments have been excluded from the segment operating loss. Unallocated corporate expenses primarily consist of stock-based compensation expense of $0.7 million in each of the three months ended September 30, 2016 and 2015 , respectively, and stock-based compensation expense of $1.7 million and $1.8 million in the six months ended September 30, 2016 and 2015 , respectively. Additionally, unallocated corporate expenses include an impairment charge of $0.7 million for the six months ended September 30, 2015 . Total assets for the two business segments as of September 30, 2016 and March 31, 2016 are as follows (in thousands): September 30, March 31, Wind $ 26,390 $ 34,389 Grid 39,200 36,255 Corporate assets 50,163 64,674 Total $ 115,753 $ 135,318 The following table sets forth customers who represented 10% or more of the Company’s total revenues for the three and six months ended September 30, 2016 and 2015 : Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 INOX Wind Limited 68 % 66 % 51 % 55 % Beijing JINGCHENG New Energy Co., Ltd — % <10% <10% 15 %

Recent Accounting Pronouncement

Recent Accounting Pronouncements	6 Months Ended
	Sep. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB and the International Accounting Standards Board (IASB) issued ASU 2014-09, ASU Revenue from Contracts with Customers (Topic 606), The guidance substantially converges final standards on revenue recognition between the FASB and IASB providing a framework on addressing revenue recognition issues and, upon its effective date, replaces almost all existing revenue recognition guidance, including industry-specific guidance, in current U.S. generally accepted accounting principles. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact the adoption of ASU 2014-09 may have on its current practices. In July 2014, the FASB issued ASU 2014-12, Compensation - Stock Compensation (Topic 718): Accounting for Share Based Payments When the Terms of an Award Provide that a Performance Target could be Achieved after the Requisite Service Period. To account for such awards, a reporting entity should apply existing guidance in FASB Accounting Standards Codification Topic 718, Compensation - Stock Compensation , as it relates to awards with performance conditions that affect vesting. As such, the performance target should not be reflected in estimating the grant-date fair value of the award. The Company adopted ASU 2014-12 effective April 1, 2016 and concludes that there is no material impact on its current practices. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern. The new standard explicitly requires the assessment at interim and annual periods, and provides management with its own disclosure guidance. This ASU is effective for annual reporting periods ending after December 15, 2016 and interim periods within annual periods beginning after December 15, 2016. The Company is currently evaluating the impact, if any, the adoption of ASU 2014-15 may have on its current practices. In April 2015, the FASB issued ASU 2015-03 Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in ASU 2015-03 require an entity to present debt issuance costs on the balance sheet as a direct deduction from the related debt liability as opposed to an asset. Amortization of the costs will continue to be reported as interest expense. The Company adopted ASU 2015-03 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In June 2015, the FASB issued ASU 2015-10 Technical Corrections and Improvements. The amendments in ASU 2015-10 clarify and correct some of the differences that arose between original guidance from FASB, EITF and other sources, and the translation into the new Codification. The Company adopted ASU 2015-10 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In July 2015, the FASB issued ASU 2015-11 Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in ASU 2015-11 clarify the proper way to identify market value in the use of lower of cost or market value valuation method. As market value could be determined multiple ways under prior standards, it will now be considered as net realizable value. This ASU is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those fiscal years. The Company is currently evaluating the impact, if any, the adoption of ASU 2015-11 may have on its current practices. In September 2015, the FASB issued ASU 2015-16 Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments. The amendments in ASU 2015-16 require that an acquirer recognize adjustments to provisional amounts identified during the measurement period in the reporting period in which the adjustment amounts are determined. The Company adopted ASU 2015-16 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In January 2016, the FASB issued ASU 2016-01 Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in ASU 2016-01 will enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. This ASU is effective for annual reporting periods beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-01 may have on its current practices. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The guidance in this ASU supersedes the leasing guidance in Topic 840, Leases. Under the new guidance, lessees are required to recognize lease assets and lease liabilities on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is currently evaluating the effects adoption of this guidance will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-08 Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) . The amendments in ASU 2016-08 clarify the implementation guidance on principal versus agent consideration. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-08 may have on its current practices. In March 2016, the FASB issued ASU 2016-09 Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . The amendments in ASU 2016-09 will simplify several aspects of the accounting for share-based payment transactions, including tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The ASU is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-09 may have on its current practices. In April 2016, the FASB issued ASU 2016-10 Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing . The amendments in ASU 2016-10 will clarify the identification of performance obligations and the licensing implementation guidance. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-10 may have on its current practices. In April 2016, the FASB issued ASU 2016-12 Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients . The amendments in ASU 2016-12 will clarify the prior guidance surrounding collectability criteria, presentation of taxes collected, non-cash consideration, contract modifications, completed contracts at completion and retrospective application guidance. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact the adoption of ASU 2016-12 may have on its current practices. In June 2016, the FASB issued ASU 2016-13 Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments in ASU 2016-13 will provide more decision useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The ASU is effective for annual reporting periods beginning after December 15, 2019, including interim periods within that year. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-13 may have on its current practices. In August 2016, the FASB issued ASU 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . The amendments in ASU 2016-15 will provide more guidance towards the classification of multiple different types of cash flows in order to reduce the diversity in reporting across entities. The ASU is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that year. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-15 may have on its current practices.

Subsequent Events

Subsequent Events	6 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has performed an evaluation of subsequent events through the time of filing this Quarterly Report on Form 10-Q with the SEC, and has determined that there are no such events to report.

Nature of the Business and Op23

Nature of the Business and Operations and Liquidity (Policies)	6 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Operations	These unaudited condensed consolidated financial statements of the Company have been prepared on a going concern basis in accordance with United States generally accepted accounting principles (“GAAP”) and the Securities and Exchange Commission’s (“SEC”) instructions to Form 10-Q. The going concern basis of presentation assumes that the Company will continue operations and will be able to realize its assets and discharge its liabilities and commitments in the normal course of business. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those instructions. The year-end condensed balance sheet data was derived from audited financial statements but does not include all disclosures required by GAAP. The unaudited condensed consolidated financial statements, in the opinion of management, reflect all adjustments (consisting of normal recurring adjustments) necessary for a fair statement of the results for the interim periods ended September 30, 2016 and 2015 and the financial position at September 30, 2016 .
Recent Accounting Pronouncements	In May 2014, the FASB and the International Accounting Standards Board (IASB) issued ASU 2014-09, ASU Revenue from Contracts with Customers (Topic 606), The guidance substantially converges final standards on revenue recognition between the FASB and IASB providing a framework on addressing revenue recognition issues and, upon its effective date, replaces almost all existing revenue recognition guidance, including industry-specific guidance, in current U.S. generally accepted accounting principles. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact the adoption of ASU 2014-09 may have on its current practices. In July 2014, the FASB issued ASU 2014-12, Compensation - Stock Compensation (Topic 718): Accounting for Share Based Payments When the Terms of an Award Provide that a Performance Target could be Achieved after the Requisite Service Period. To account for such awards, a reporting entity should apply existing guidance in FASB Accounting Standards Codification Topic 718, Compensation - Stock Compensation , as it relates to awards with performance conditions that affect vesting. As such, the performance target should not be reflected in estimating the grant-date fair value of the award. The Company adopted ASU 2014-12 effective April 1, 2016 and concludes that there is no material impact on its current practices. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern. The new standard explicitly requires the assessment at interim and annual periods, and provides management with its own disclosure guidance. This ASU is effective for annual reporting periods ending after December 15, 2016 and interim periods within annual periods beginning after December 15, 2016. The Company is currently evaluating the impact, if any, the adoption of ASU 2014-15 may have on its current practices. In April 2015, the FASB issued ASU 2015-03 Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in ASU 2015-03 require an entity to present debt issuance costs on the balance sheet as a direct deduction from the related debt liability as opposed to an asset. Amortization of the costs will continue to be reported as interest expense. The Company adopted ASU 2015-03 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In June 2015, the FASB issued ASU 2015-10 Technical Corrections and Improvements. The amendments in ASU 2015-10 clarify and correct some of the differences that arose between original guidance from FASB, EITF and other sources, and the translation into the new Codification. The Company adopted ASU 2015-10 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In July 2015, the FASB issued ASU 2015-11 Inventory (Topic 330): Simplifying the Measurement of Inventory. The amendments in ASU 2015-11 clarify the proper way to identify market value in the use of lower of cost or market value valuation method. As market value could be determined multiple ways under prior standards, it will now be considered as net realizable value. This ASU is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those fiscal years. The Company is currently evaluating the impact, if any, the adoption of ASU 2015-11 may have on its current practices. In September 2015, the FASB issued ASU 2015-16 Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments. The amendments in ASU 2015-16 require that an acquirer recognize adjustments to provisional amounts identified during the measurement period in the reporting period in which the adjustment amounts are determined. The Company adopted ASU 2015-16 effective April 1, 2016 and concludes that there is no material impact on its consolidated results of operations, financial condition, or cash flow. In January 2016, the FASB issued ASU 2016-01 Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in ASU 2016-01 will enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. This ASU is effective for annual reporting periods beginning after December 15, 2017, and interim periods within those fiscal years. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-01 may have on its current practices. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The guidance in this ASU supersedes the leasing guidance in Topic 840, Leases. Under the new guidance, lessees are required to recognize lease assets and lease liabilities on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is currently evaluating the effects adoption of this guidance will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-08 Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) . The amendments in ASU 2016-08 clarify the implementation guidance on principal versus agent consideration. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-08 may have on its current practices. In March 2016, the FASB issued ASU 2016-09 Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . The amendments in ASU 2016-09 will simplify several aspects of the accounting for share-based payment transactions, including tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The ASU is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-09 may have on its current practices. In April 2016, the FASB issued ASU 2016-10 Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing . The amendments in ASU 2016-10 will clarify the identification of performance obligations and the licensing implementation guidance. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-10 may have on its current practices. In April 2016, the FASB issued ASU 2016-12 Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients . The amendments in ASU 2016-12 will clarify the prior guidance surrounding collectability criteria, presentation of taxes collected, non-cash consideration, contract modifications, completed contracts at completion and retrospective application guidance. The ASU is effective for annual reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact the adoption of ASU 2016-12 may have on its current practices. In June 2016, the FASB issued ASU 2016-13 Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . The amendments in ASU 2016-13 will provide more decision useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The ASU is effective for annual reporting periods beginning after December 15, 2019, including interim periods within that year. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-13 may have on its current practices. In August 2016, the FASB issued ASU 2016-15 Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . The amendments in ASU 2016-15 will provide more guidance towards the classification of multiple different types of cash flows in order to reduce the diversity in reporting across entities. The ASU is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that year. The Company is currently evaluating the impact, if any, the adoption of ASU 2016-15 may have on its current practices.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-Based Compensation Expense	The Company accounts for its stock-based compensation at fair value. The following table summarizes stock-based compensation expense by financial statement line item for the three and six months ended September 30, 2016 and 2015 (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Cost of revenues $ 49 $ 61 $ 99 $ 158 Research and development 62 87 92 283 Selling, general and administrative 542 558 1,462 1,393 Total $ 653 $ 706 $ 1,653 $ 1,834
Schedule of Share-Based Compensation Valuation Assumptions	The weighted average assumptions used in the Black Scholes valuation model for stock options granted during the six months ended September 30, 2016 are as follows: Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Expected volatility 67.6 % N/A 67.6 % N/A Risk-free interest rate 1.3 % N/A 1.3 % N/A Expected life (years) 5.7 N/A 5.7 N/A Dividend yield None N/A None N/A

Computation of Net Loss per C25

Computation of Net Loss per Common Share (Tables)	6 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Reconciliation of Numerators and Denominators of EPS Calculation	The following table reconciles the numerators and denominators of the earnings per share calculation for the three and six months ended September 30, 2016 and 2015 (in thousands, except per share data): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Numerator: Net loss (7,325 ) (7,698 ) $ (17,680 ) $ (16,819 ) Denominator: Weighted-average shares of common stock outstanding 14,190 14,054 14,161 12,958 Weighted-average shares subject to repurchase (421 ) (459 ) (438 ) (150 ) Shares used in per-share calculation ― basic 13,769 13,595 13,723 12,808 Shares used in per-share calculation ― diluted 13,769 13,595 13,723 12,808 Net loss per share ― basic (0.53 ) (0.57 ) $ (1.29 ) $ (1.31 ) Net loss per share ― diluted (0.53 ) (0.57 ) $ (1.29 ) $ (1.31 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Carried at Fair Value on Recurring Basis	The following table provides the assets and liabilities carried at fair value on a recurring basis, measured as of September 30, 2016 and March 31, 2016 (in thousands): Total Carrying Value Quoted Prices in Active Markets ( Level 1) Significant Other Observable Inputs ( Level 2) Significant Unobservable Inputs ( Level 3) September 30, 2016: Assets: Cash equivalents $ 14,077 $ 14,077 $ — $ — Derivative liabilities: Warrants $ 2,660 $ — $ — $ 2,660 Total Quoted Prices in Significant Other Significant March 31, 2016: Assets: Cash equivalents $ 16,040 $ 16,040 $ — $ — Derivative liabilities: Warrants $ 3,227 $ — $ — $ 3,227
Schedule of Liabilities Measured at Fair Value on Recurring Basis	The table below reflects the activity for the Company’s major classes of liabilities measured at fair value on a recurring basis (in thousands): Warrants April 1, 2016 $ 3,227 Mark to market adjustment (567 ) Balance at September 30, 2016 $ 2,660 Warrants April 1, 2015 $ 2,999 Mark to market adjustment 228 Balance at March 31, 2016 $ 3,227

Accounts Receivable (Tables)

Accounts Receivable (Tables)	6 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Schedule of Accounts Receivable	Accounts receivable at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Accounts receivable (billed) $ 11,417 $ 18,089 Accounts receivable (unbilled) 767 1,229 Less: Allowance for doubtful accounts (54 ) (54 ) Accounts receivable, net $ 12,130 $ 19,264

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Raw materials $ 11,233 $ 9,665 Work-in-process 2,349 3,411 Finished goods 6,429 3,215 Deferred program costs 6,437 2,221 Net inventory $ 26,448 $ 18,512

Accounts Payable and Accrued 29

Accounts Payable and Accrued Expenses (Tables)	6 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses at September 30, 2016 and March 31, 2016 consisted of the following (in thousands): September 30, March 31, Accounts payable $ 6,262 $ 5,837 Accrued inventories in-transit 1,804 1,908 Accrued other miscellaneous expenses 2,431 3,003 Accrued compensation 4,093 7,526 Income taxes payable 1,297 1,281 Accrued warranty 2,694 3,601 Total $ 18,581 $ 23,156
Schedule of Product Warranty Activity	Product warranty activity was as follows (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Balance at beginning of period $ 2,774 $ 3,344 $ 3,601 $ 3,934 Change in accruals for warranties during the period 316 429 417 423 Settlements during the period (396 ) (500 ) (1,324 ) (1,084 ) Balance at end of period $ 2,694 $ 3,273 $ 2,694 $ 3,273

Warrants and Derivative Liabi30

Warrants and Derivative Liabilities (Tables)	6 Months Ended
	Sep. 30, 2016
Exchanged Warrants
Class Of Warrant Or Right [Line Items]
Schedule of Assumptions Used to Calculate the Fair Value of Warrants	Following is a summary of the key assumptions used to calculate the fair value of the Exchanged Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.59% 0.48% Expected annual dividend yield — — Expected volatility 70.50% 76.30% Term (years) 1.01 1.26 Fair value $0.2 million $0.4 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 0.66% 0.96% 0.64% 0.74% 0.73% Expected annual dividend yield — — — — — Expected volatility 76.76% 76.68% 73.39% 71.61% 70.42% Term (years) 1.51 1.76 2.01 2.26 2.51 Fair value $0.4 million $0.3 million $0.1 million $0.2 million $0.3 million
Hercules Warrants
Class Of Warrant Or Right [Line Items]
Schedule of Assumptions Used to Calculate the Fair Value of Warrants	Following is a summary of the key assumptions used to calculate the fair value of the Hercules Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.97% 0.86% Expected annual dividend yield — — Expected volatility 67.98% 68.34% Term (years) 3.75 4.00 Fair value $0.2 million $0.3 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 1.08% 1.65% 1.31% 1.63% 1.41% Expected annual dividend yield — — — — — Expected volatility 70.25% 73.57% 75.32% 72.57% 74.60% Term (years) 4.25 4.50 4.75 5.00 5.25 Fair value $0.2 million $0.2 million $0.1 million $0.2 million $0.2 million
November 2014 Warrant
Class Of Warrant Or Right [Line Items]
Schedule of Assumptions Used to Calculate the Fair Value of Warrants	Following is a summary of the key assumptions used to calculate the fair value of the November 2014 Warrant: Fiscal Year 16 September 30, June 30, 2016 Risk-free interest rate 0.93% 0.77% Expected annual dividend yield — — Expected volatility 68.96% 70.01% Term (years) 3.12 3.37 Fair value $2.3 million $3.2 million Fiscal Year 15 March 31, 2016 December 31, 2015 September 30, 2015 June 30, 2015 March 31, Risk-free interest rate 0.98% 1.51% 1.17% 1.44% 1.28% Expected annual dividend yield — — — — — Expected volatility 69.88% 70.02% 73.02% 74.18% 75.96% Term (years) 3.62 3.87 4.12 4.37 4.62 Fair value $2.6 million $2.1 million $1.3 million $1.8 million $2.5 million

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Schedule of Operating Results for Business Segments	The operating results for the two business segments are as follows (in thousands): Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Revenues : Wind $ 12,898 $ 13,583 $ 18,573 $ 31,747 Grid 5,609 5,421 13,279 10,980 Total $ 18,507 $ 19,004 $ 31,852 $ 42,727 Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 Operating (loss) profit: Wind $ (1,235 ) $ (1,991 ) $ (4,264 ) $ (1,864 ) Grid (5,262 ) (4,113 ) (10,577 ) (10,621 ) Unallocated corporate expenses (653 ) (737 ) (1,653 ) (2,613 ) Total $ (7,150 ) $ (6,841 ) $ (16,494 ) $ (15,098 )
Schedule of Total Assets for Segments	Total assets for the two business segments as of September 30, 2016 and March 31, 2016 are as follows (in thousands): September 30, March 31, Wind $ 26,390 $ 34,389 Grid 39,200 36,255 Corporate assets 50,163 64,674 Total $ 115,753 $ 135,318
Schedule of Revenues by Major Customers	The following table sets forth customers who represented 10% or more of the Company’s total revenues for the three and six months ended September 30, 2016 and 2015 : Three months ended September 30, Six months ended September 30, 2016 2015 2016 2015 INOX Wind Limited 68 % 66 % 51 % 55 % Beijing JINGCHENG New Energy Co., Ltd — % <10% <10% 15 %

Nature of the Business and Op32

Nature of the Business and Operations and Liquidity - Additional Information (Detail) $ in Thousands	Apr. 29, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2016USD ($)employee	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)employee	Sep. 30, 2016USD ($)employee	Mar. 31, 2015USD ($)
Description Of Business [Line Items]
Accumulated deficit				$ (928,184)	$ (945,864)		$ (945,864)	$ (945,864)
Cash and cash equivalents				39,330	25,262	$ 32,572	$ 25,262	$ 25,262	$ 20,490
Net cash used in operating activities					$ 10,912	7,767
Number of workforce persons | employee					366		366	366
Cash flows from financing activities					$ (2,490)	$ 20,202		$ 68,500
Proceeds from additional equity offering	$ 22,300
Tres Amigas
Description Of Business [Line Items]
Minority investment, percentage of investment sold							100.00%
Minority share investment proceeds				$ 300			$ 600
Tres Amigas | Scenario, Forecast
Description Of Business [Line Items]
Minority share investment proceeds			$ 300
Maximum | Tres Amigas
Description Of Business [Line Items]
Minority share investment proceeds							$ 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

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 653	$ 706	$ 1,653	$ 1,834
Cost of revenues
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	49	61	99	158
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	62	87	92	283
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 542	$ 558	$ 1,462	$ 1,393

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Restricted stock and stock awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock granted (in shares)			161,000	392,689
Unrecognized compensation cost for unvested employee stock-based compensation awards outstanding, net of forfeitures	$ 2.8		$ 2.8
Weighted-average period over which unrecognized compensation expense is expected to be recognized			1 year 9 months 30 days
Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted in period (in shares)	9,703	0	9,703	0
Unrecognized compensation cost for unvested employee stock-based compensation awards outstanding, net of forfeitures	$ 0.5		$ 0.5
Weighted-average period over which unrecognized compensation expense is expected to be recognized			2 years 5 months 12 days
Minimum | Restricted stock and stock awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			2 years
Minimum | Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			2 years
Maximum | Restricted stock and stock awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years
Maximum | Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Share-Based Compensation Valuation Assumptions (Details) - Stock options	3 Months Ended	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	67.60%	67.60%
Risk-free interest rate	1.30%	1.30%
Expected life	5 years 8 months 13 days	5 years 8 months 13 days
Dividend yield	0.00%	0.00%

Computation of Net Loss per C36

Computation of Net Loss per Common Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted EPS (in shares)	1.6	0	1.6	0
Stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted EPS (in shares)	0.4	0	0	0
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted EPS (in shares)	1.2	1.2	1.2	1.2

Computation of Net Loss per C37

Computation of Net Loss per Common Share - Reconciliation of Numerators and Denominators of EPS Calculation (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net loss	$ (7,325)	$ (7,698)	$ (17,680)	$ (16,819)
Denominator:
Weighted-average shares of common stock outstanding (in shares)	14,190	14,054	14,161	12,958
Weighted-average shares subject to repurchase (in shares)	(421)	(459)	(438)	(150)
Shares used in per-share calculation ― basic (in shares)	13,769	13,595	13,723	12,808
Shares used in per-share calculation ― diluted (in shares)	13,769	13,595	13,723	12,808
Net loss per share ― basic (in dollars per share)	$ (0.53)	$ (0.57)	$ (1.29)	$ (1.31)
Net loss per share ― diluted (in dollars per share)	$ (0.53)	$ (0.57)	$ (1.29)	$ (1.31)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Carried at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants	$ 2,660	$ 3,227
Reported Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	14,077	16,040
Warrants	2,660	3,227
Reported Value Measurement | Quoted Prices in Active Markets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	14,077	16,040
Warrants	0	0
Reported Value Measurement | Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Warrants	0	0
Reported Value Measurement | Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Warrants	$ 2,660	$ 3,227

Fair Value Measurements - Sch39

Fair Value Measurements - Schedule of Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 3,227
Ending balance	2,660	$ 3,227
Warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3,227	2,999
Mark to market adjustment	(567)	228
Ending balance	$ 2,660	$ 3,227

Accounts Receivable - Schedule

Accounts Receivable - Schedule of Accounts Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Receivables [Abstract]
Accounts receivable (billed)	$ 11,417	$ 18,089
Accounts receivable (unbilled)	767	1,229
Less: Allowance for doubtful accounts	(54)	(54)
Accounts receivable, net	$ 12,130	$ 19,264

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 11,233	$ 9,665
Work-in-process	2,349	3,411
Finished goods	6,429	3,215
Deferred program costs	6,437	2,221
Net inventory	$ 26,448	$ 18,512

Inventory - Additional Informat

Inventory - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Inventory Disclosure [Abstract]
Inventory write-down	$ 400	$ 200	$ 671	$ 829

Accounts Payable and Accrued 43

Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 6,262		$ 5,837
Accrued inventories in-transit	1,804		1,908
Accrued other miscellaneous expenses	2,431		3,003
Accrued compensation	4,093		7,526
Income taxes payable	1,297		1,281
Accrued warranty	2,694	$ 2,774	3,601	$ 3,273	$ 3,344	$ 3,934
Total	$ 18,581		$ 23,156

Accounts Payable and Accrued 44

Accounts Payable and Accrued Expenses - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2016
Minimum
Product Warranty Liability [Line Items]
Warranty period	1 year
Maximum
Product Warranty Liability [Line Items]
Warranty period	3 years

Accounts Payable and Accrued 45

Accounts Payable and Accrued Expenses - Schedule of Product Warranty Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Movement in Extended Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 2,774	$ 3,344	$ 3,601	$ 3,934
Change in accruals for warranties during the period	316	429	417	423
Settlements during the period	(396)	(500)	(1,324)	(1,084)
Balance at end of period	$ 2,694	$ 3,273	$ 2,694	$ 3,273

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 794	$ 875	$ 1,117	$ 1,450

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Apr. 29, 2015	Dec. 19, 2014	Nov. 15, 2013	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Proceeds from additional equity offering (more than)	$ 22,300,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				$ 100,000	$ 100,000	$ 100,000	$ 200,000
FIrst Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		13,927
Fair value of warrants issued		$ 400,000
Second Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		25,641
Fair value of warrants issued		$ 200,000
Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		58,823
Warrant exercise price (in dollars per share)	$ 9.41	$ 11
Term Loan
Debt Instrument [Line Items]
Interest expense, debt				100,000	300,000	300,000	600,000
Term Loan | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Covenant, unrestricted cash balance requirement				2,000,000		2,000,000
Term Loan B | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt, face amount			$ 10,000,000
Net proceeds from debt			$ 9,800,000
Interest rate, stated percentage			11.00%
Outstanding principal balance				700,000		700,000
End of term fee						500,000
Minimum amount of proceeds from specified asset dispositions for mandatory prepayment feature				1,000,000		1,000,000
Debt discount			$ 200,000
Term Loan B | Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Unamortized discount (premium) and debt issuance costs		$ 1,000,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				100,000	100,000	100,000
Term Loan C | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt, face amount		1,500,000
Net proceeds from debt		$ 1,400,000
Interest rate, stated percentage		11.00%
End of term fee						$ 100,000
Debt discount			$ 100,000
Debt instrument, maturity date						Jun. 1, 2017
Proceeds from additional equity offering (more than)				10,000,000
Term Loan C | Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Unamortized discount (premium) and debt issuance costs		$ 300,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				$ 100,000	$ 100,000	$ 100,000	$ 100,000
Prime Rate | Term Loan B | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt instrument, basis spread on prime rate			3.75%
Prime Rate | Term Loan C | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt instrument, basis spread on prime rate		3.75%

Warrants and Derivative Liabi48

Warrants and Derivative Liabilities - Additional Information (Detail) $ / shares in Units, $ in Thousands	Dec. 19, 2014$ / sharesshares	Apr. 04, 2012shares	Oct. 31, 2013$ / shares	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Apr. 29, 2015$ / shares	Nov. 13, 2014shares / pure$ / sharesshares
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million for three months ended 2015) | $				$ 1,244	$ 701	$ 567	$ 1,501
Sale of stock, price per share (in dollars per share)								$ 6
Hercules Warrants
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million for three months ended 2015) | $				100	100	100	100
November 2014 Warrant
Derivative [Line Items]
Warrant exercise price (in dollars per share)								9.41
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million for three months ended 2015) | $				900	500	$ 300	1,200
Warrants expiration date						Nov. 13, 2019
Common stock units offered (in shares) | shares									909,090
Warrants to purchase one share of common stock									0.9
Number of warrants issued to purchase common stock (in shares) | shares									818,181
Sale of stock, price per share (in dollars per share)									$ 11
Capital Ventures International | Exchanged Warrants
Derivative [Line Items]
Gain (loss) in change of fair value of derivative instruments and warrants (less than $0.1 million for three months ended 2015) | $				$ 200	$ 100	$ 200	$ 200
Senior Convertible Note warrant | Capital Ventures International | Original Warrants
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares) | shares		309,406
Senior Convertible Note warrant | Capital Ventures International | Exchanged Warrants
Derivative [Line Items]
Warrant exercise, waiting period			6 months
Warrant exercise period			5 years
Warrant exercise price (in dollars per share)			$ 15.94
Senior Convertible Note warrant | Capital Ventures International | Maximum | Exchanged Warrants
Derivative [Line Items]
Beneficial ownership limitation percentage			4.99%
Beneficial ownership, limitation option, percentage			9.99%
Required notification period			61 days
Senior Secured Loan | Hercules Technology Growth Capital | Hercules Warrants
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares) | shares	58,823
Warrant exercise price (in dollars per share)	$ 11							$ 9.41
Warrants expiration date						Jun. 30, 2020

Warrants and Derivative Liabi49

Warrants and Derivative Liabilities - Schedule of Assumptions Used to Calculate the Fair Value of Exchanged Warrants (Detail) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Exchanged Warrants
Derivative [Line Items]
Risk-free interest rate	0.59%	0.48%	0.66%	0.96%	0.64%	0.74%	0.73%
Expected annual dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Expected volatility	70.50%	76.30%	76.76%	76.68%	73.39%	71.61%	70.42%
Term	1 year 4 days	1 year 3 months 4 days	1 year 6 months 4 days	1 year 9 months 4 days	2 years 4 days	2 years 3 months 4 days	2 years 6 months 4 days
Fair value	$ 0.2	$ 0.4	$ 0.4	$ 0.3	$ 0.1	$ 0.2	$ 0.3
Hercules Warrants
Derivative [Line Items]
Risk-free interest rate	0.97%	0.86%	1.08%	1.65%	1.31%	1.63%	1.41%
Expected annual dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Expected volatility	67.98%	68.34%	70.25%	73.57%	75.32%	72.57%	74.60%
Term	3 years 9 months	4 years	4 years 3 months	4 years 6 months	4 years 9 months	5 years	5 years 3 months
Fair value	$ 0.2	$ 0.3	$ 0.2	$ 0.2	$ 0.1	$ 0.2	$ 0.2
November 2014 Warrant
Derivative [Line Items]
Risk-free interest rate	0.93%	0.77%	0.98%	1.51%	1.17%	1.44%	1.28%
Expected annual dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Expected volatility	68.96%	70.01%	69.88%	70.02%	73.02%	74.18%	75.96%
Term	3 years 1 month 13 days	3 years 4 months 13 days	3 years 7 months 13 days	3 years 10 months 13 days	4 years 1 month 13 days	4 years 4 months 13 days	4 years 7 months 13 days
Fair value	$ 2.3	$ 3.2	$ 2.6	$ 2.1	$ 1.3	$ 1.8	$ 2.5

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Millions	Apr. 29, 2015USD ($)$ / sharesshares
Equity [Abstract]
Common stock, shares issued | shares	4,000,000
Sale of stock, price per share (in dollars per share) | $ / shares	$ 6
Proceeds from additional equity offering | $	$ 22.3

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands, ¥ in Millions	Feb. 27, 2012USD ($)	Feb. 27, 2012CNY (¥)	Oct. 08, 2011USD ($)	Oct. 08, 2011CNY (¥)	Sep. 13, 2011USD ($)	Sep. 13, 2011CNY (¥)	Mar. 31, 2011USD ($)	Mar. 31, 2011CNY (¥)	Sep. 30, 2016USD ($)	Mar. 31, 2016USD ($)
Commitments And Contingencies [Line Items]
Restricted cash included in current assets									$ 452	$ 457
Restricted cash included in long-term assets									$ 934	$ 934
Sinovel Wind Group Co. Ltd.
Commitments And Contingencies [Line Items]
Sought compensation amount	$ 16,000	¥ 105	$ 180,000	¥ 1,200	$ 73,000	¥ 485
Value of the undelivered components							$ 690,000	¥ 4,600

Minority Investments - Addition

Minority Investments - Additional Information (Detail) - Tres Amigas $ in Millions	3 Months Ended			7 Months Ended
	Dec. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Jun. 30, 2015USD ($)	Sep. 30, 2016USD ($)power_grid
Schedule Of Equity Method Investments [Line Items]
Number of commonly interconnected power grids | power_grid				3
Minority investment, aggregate cost				$ 5.4
Impairment of minority interest investments			$ 0.7
Minority investment, percentage of investment sold				100.00%
Minority share investment proceeds		$ 0.3		$ 0.6
Scenario, Forecast
Schedule Of Equity Method Investments [Line Items]
Minority share investment proceeds	$ 0.3
Maximum
Schedule Of Equity Method Investments [Line Items]
Minority share investment proceeds				$ 0.6

Business Segments - Additional

Business Segments - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)segmentMW	Sep. 30, 2015USD ($)
Segment Reporting Information [Line Items]
Number of reportable business segments | segment			2
Stock-based compensation expense	$ 653	$ 706	$ 1,653	$ 1,834
Impairment of minority interest investment			$ 0	746
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	$ 700	700	$ 1,700	$ 1,800
Impairment of minority interest investment		$ 700

Business Segments - Operating R

Business Segments - Operating Results for Two Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 18,507	$ 19,004	$ 31,852	$ 42,727
Operating (loss) profit	(7,150)	(6,841)	(16,494)	(15,098)
Unallocated corporate expenses
Segment Reporting Information [Line Items]
Operating (loss) profit	(653)	(737)	(1,653)	(2,613)
Wind | Operating Segments
Segment Reporting Information [Line Items]
Revenues	12,898	13,583	18,573	31,747
Operating (loss) profit	(1,235)	(1,991)	(4,264)	(1,864)
Grid | Operating Segments
Segment Reporting Information [Line Items]
Revenues	5,609	5,421	13,279	10,980
Operating (loss) profit	$ (5,262)	$ (4,113)	$ (10,577)	$ (10,621)

Business Segments - Total Busin

Business Segments - Total Business Segments Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	$ 115,753	$ 135,318
Operating Segments | Wind
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	26,390	34,389
Operating Segments | Grid
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	39,200	36,255
Corporate assets
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	$ 50,163	$ 64,674

Business Segments - Schedule of

Business Segments - Schedule of Revenues by Major Customers (Detail) - Total Revenue - Customer Concentration Risk	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
INOX Wind Limited
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% 3 months ended 2015, nine months ended 2016)	68.00%	66.00%	51.00%	55.00%
Beijing JINGCHENG New Energy Co., Ltd
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% 3 months ended 2015, nine months ended 2016)	0.00%	10.00%	10.00%	15.00%