Additional Balance Sheet Information - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Disclosure Text Block Supplement [Abstract]
Prepaid research and development	$ 580	$ 574
Tenant improvement allowance receivable	42	586
Prepaid insurance	90	301
Prepaid other	285	89
Other receivables	21	100
Prepaid expenses and other current assets	$ 1,018	$ 1,650

Amount of asset related to consideration paid in advance for insurance that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

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Name:	us-gaap_PrepaidInsurance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant