Hercules Loan Facility - Future Minimum Payments Under Loans Payable (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
2022 (remaining nine months)	$ 3,021
2023	22,594
2024	24,449
Long-term debt, gross	50,064
Less amount representing interest	(7,284)
Less unamortized discount	(1,811)	$ (2,000)
Less deferred charges	(2,780)
Loans payable, net of discount	$ 38,189	$ 37,960

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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.

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Amount, after accumulated amortization, of debt discount.

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The total amount of long-term liability charges that are being deferred beyond one year.

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Carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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