Fair Value Measurements - Fair Value of Liabilities Measured on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value of liabilities measured on a recurring basis
Warrant liability	$ 179	$ 3
Total fair value	179	3
Level 3
Fair value of liabilities measured on a recurring basis
Warrant liability	179	3
Total fair value	$ 179	$ 3

Fair value portion of warrants not settleable in cash classified as equity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_WarrantsNotSettleableInCashFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant