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Summary of Significant Accounting Policies - Additional Information (Details) |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 27, 2020 USD ($) | Mar. 26, 2020 | Jul. 31, 2016 | Jun. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) | Dec. 31, 2020 USD ($) segment shares | Dec. 31, 2019 USD ($) shares | Jan. 01, 2019 USD ($) | Dec. 31, 2018 USD ($)
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Number of Reportable Segments | segment |  |  |  |  |  | 1 |  |  |
Goodwill impairment loss |  |  |  |  |  | $ 0 | $ 0 |  |
Operating Lease, Right-of-Use Asset |  |  |  |  |  | 6,559,000 | 8,048,000 |  |
Operating Lease, Liability |  |  |  |  |  | 6,630,000 | 8,106,000 |  |
Cylinder deposit liability |  |  |  |  |  | 10,800,000 | 9,500,000 |  |
Contract term |  |  | 5 years |  |  |  |  |  |
Contract renewal term |  |  | 5 years |  |  |  |  |  |
Additional tax benefit related to the alternative minimum tax refund |  |  |  | $ 380,000 |  |  |  |  |
Operating Loss Carryforwards |  |  |  |  |  | 46,100,000 |  |  |
Deferred Tax Assets, Valuation Allowance |  |  |  |  |  | 19,033,000 | $ 18,918,000 |  | $ 11,300,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount |  |  |  |  |  | $ 19,000,000 |  |  |
Options and warrants excluded from the calculation of diluted shares | shares |  |  |  |  |  | 5,329,515 | 7,042,377 |  |
No Expiration [Member] |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Loss Carryforwards |  |  |  |  |  | $ 40,700,000 |  |  |
Expiring Through 2023 [Member] |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Loss Carryforwards |  |  |  |  |  | 5,400,000 |  |  |
State and Local Jurisdiction [Member] |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Loss Carryforwards |  |  |  |  |  | $ 31,200,000 |  |  |
ASU Topic 842 [Member] |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Lease, Right-of-Use Asset |  |  |  |  |  |  |  | $ 8,100,000 |
Operating Lease, Liability |  |  |  |  |  |  |  | $ 8,100,000 |
Customer Concentration Risk [Member] | One Customer | Revenue from Contract with Customer [Member] |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Concentration Risk, Percentage |  |  |  |  |  | 14.00% | 14.00% |  |
Customer Concentration Risk [Member] | One Customer | Accounts Receivable |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Accounts Receivable, net |  |  |  |  |  | $ 2,900,000 | $ 1,800,000 |  |
CARES Act |  |  |  |  |  |  |  |  |
Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percent of taxable income offset for taxable years beginning before 2021 | 100.00% |  |  |  |  |  |  |  |
Preliminary tax benefit related to the alternative minimum tax refund |  |  |  |  | $ 47,000 |  |  |  |
Percent of adjusted taxable income | 50.00% | 30.00% |  |  |  |  |  |  |
Increase in allowable interest expense | $ 2,154,000 |  |  |  |  |  |  |  |
Operating Loss Carryforwards |  |  |  |  |  | $ 2,154,000 |  |  |

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