Composition of Certain Consolidated Financial Statement Items - Interest and Other Income (Expense), net (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest income	$ 22	$ 23	$ 49	$ 161
Decrease (increase) in fair value of preferred stock warrants	16	142	78	233
Decrease (increase) in fair value of loan facility derivative liability	177	174	158	(41)
Interest and other income, net	(52)	18	(87)	(9)
Total interest and other income (expense), net	$ 163	$ 357	$ 198	$ 344

Interest And Other Income (Expense)

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- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

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-Name Accounting Standards Codification
-Topic 230
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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of income (expense) related to nonoperating activities, classified as other.

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