Balance Sheet Details - Property Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 831	$ 1,352
Accumulated depreciation and amortization	(691)	(1,137)
Total property and equipment, net	140	215
Computer Hardware [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, gross	319	310
Furniture and Fixtures [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, gross	309	309
Software [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 203	$ 733

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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