Note 8 - Long-term Debt (Details Textual) - USD ($)
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12 Months Ended |
Aug. 01, 2019 |
May 30, 2019 |
Dec. 31, 2021 |
Dec. 31, 2020 |
| Repayments of Long-term Debt, Total |
|
|
$ 8,833,000
|
$ 4,667,000
|
| Long-term Debt, Total |
|
|
13,803,000
|
|
| Amortization of Debt Discount (Premium) |
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|
761,000
|
$ 1,069,000
|
| Leasehold Improvements, Gross |
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|
$ 1,700,000
|
|
| Site Readiness Agreement [Member] |
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| Debt Instrument, Interest Rate, Effective Percentage |
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14.35%
|
14.35%
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| Debt Instrument, Periodic Payment, Principal |
$ 500,000
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|
|
| Total Obligation Under Leasehold Agreement |
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$ 500,000
|
$ 800,000
|
| Warrant In Connection with Oxford Finance Loan Agreement [Member] |
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| Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) |
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176,679
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| Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |
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$ 2.83
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| Loan Agreement with Oxford Finance LLC [Member] |
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| Debt Instrument, Face Amount |
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$ 25,000,000.0
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| Repayments of Long-term Debt, Total |
|
8,900,000
|
|
|
| Proceeds from Debt, Net of Issuance Costs and Repayment of Debt |
|
$ 15,900,000
|
|
|
| Debt Instrument, Interest Rate, Base Percentage |
|
2.50%
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| Prepayment Charge, Percentage of Outstanding Balance, After May 30, 2020, Before May 30, 2021 |
|
1.00%
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| Debt Instrument, Covenant, Minimum Required Unrestircted Cash |
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$ 5,000,000.0
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| Debt Instrument, Minimum Indebtedness Amount with Acceleration Right |
|
250,000
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| Loan Default Events, Trigger of Negative Impact of Government Approvals and Judgments |
|
$ 500,000
|
|
|
| Debt Instrument, Default Additional Interest Rate |
|
5.00%
|
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| Fair Value of Contingent Put Option, Liability |
|
|
100,000
|
|
| Long-term Debt, Total |
|
|
13,300,000
|
21,000,000.0
|
| Interest Expense, Debt, Total |
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|
2,200,000
|
3,200,000
|
| Amortization of Debt Discount (Premium) |
|
|
$ 700,000
|
$ 900,000
|
| Debt Instrument, Interest Rate, Effective Percentage |
|
|
13.15%
|
13.15%
|
| Loan Agreement with Oxford Finance LLC [Member] | London Interbank Offered Rate (LIBOR) [Member] |
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| Debt Instrument, Basis Spread on Variable Rate |
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6.75%
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