Summary of Significant Accounting Policies - Schedule of Other Income (Expense), Net (Detail) - USD ($) $ in Thousands |
9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Other Income and Expenses [Abstract] | ||||
| Interest income (expense), net | $ (4,198) | $ (1,341) | $ (3,890) | $ 17 |
| Stock warrants issued | (5,790) | |||
| Write-off of deferred debt discounts and issuance costs | (10,132) | |||
| Write-off of legal fees in connection with the Primary Warrant | (253) | |||
| Gain on fair value change of warrant liability | 7,114 | 117 | 950 | |
| Other | 134 | (6) | (253) | 68 |
| Other income (expense), net | $ (12,872) | $ (1,483) | $ (3,193) | $ 85 |
| X | ||||||||||
- Definition Amount of expense (income) related to adjustment to fair value of warrant liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The net amount of operating interest income (expense). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of gain (loss) related to nonoperating activities, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Costs of warrants issued. No definition available.
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| X | ||||||||||
- Definition Write off of deferred debt discounts and issuance costs. No definition available.
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| X | ||||||||||
- Definition Write-off of legal fees in connection with primary warrant. No definition available.
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