| Long-Term Debt, Net of Financing Fees - Carrying Value of Outstanding Debt (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Jun. 30, 2021 | Dec. 31, 2020 | Jun. 30, 2020 | 
|---|---|---|---|---|
| Debt Instrument [Line Items] | ||||
| Less - unamortized debt discount and deferred financing fees | $ (3,762) | $ (2,973) | ||
| Long-Term Debt, Net of Financing Fees | 46,238 | 32,027 | ||
| First Tranche | ||||
| Debt Instrument [Line Items] | ||||
| Oberland Facility | 35,000 | 35,000 | $ 35,000 | |
| Second Tranche | ||||
| Debt Instrument [Line Items] | ||||
| Oberland Facility | $ 15,000 | $ 15,000 | $ 0 | 
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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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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 of unamortized debt discount (premium) and debt issuance costs. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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