The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Summary of Significant Accounting Policies - Property and Equipment, and Impairment of Long-lived Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and Equipment, Net
Impairment losses on long-lived assets	$ 0	$ 0	$ 0
Computer hardware
Property and Equipment, Net
Estimated useful lives	3 years
Furniture and fixtures
Property and Equipment, Net
Estimated useful lives	7 years
Computer software
Property and Equipment, Net
Estimated useful lives	3 years
Office equipment
Property and Equipment, Net
Estimated useful lives	3 years