Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Name:	us-gaap_RestrictedCashAndCashEquivalentsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	May 06, 2019 USD ($)	Jul. 04, 2018 USD ($)	Jul. 03, 2018 USD ($) installment	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)
Commitments And Contingencies [Line Items]
Restricted cash included in long-term assets				$ 165	$ 165
Subsequent Event \| Sinovel Wind Group Co. Ltd.
Commitments And Contingencies [Line Items]
Proceeds from settlement			$ 57,500
Number of installments \| installment			2
Settlement, amount awarded		$ 32,500
Payment period			10 months
Forecast \| Sinovel Wind Group Co. Ltd.
Commitments And Contingencies [Line Items]
Settlement, amount awarded	$ 25,000