Schedule of Revenue, Disaggregated by Revenue Stream (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
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| Disaggregation of Revenue [Line Items] | ||||
| Revenue | $ 36,444 | $ 43,375 | $ 70,183 | $ 73,945 |
| Product [Member] | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 26,300 | 30,200 | 49,800 | 50,000 |
| Fixed-price Contract [Member] | Turnkey Energy Conservation Projects | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | $ 10,200 | $ 13,100 | $ 20,400 | $ 23,900 |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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