Concentration, Credit and Other Risks - Major Customers (Details) - Major Customers - Wecast Services - customer	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Revenue
Revenue, Major Customer [Line Items]
Description of percentage of revenue for major customer	more than 10.0%	more than 10.0%
Number of customers	3	1
Percentage of concentration risk	77.00%	91.00%
Accounts receivables
Revenue, Major Customer [Line Items]
Description of percentage of revenue for major customer	more than 10.0%	more than 10.0%
Number of customers	3	1
Percentage of concentration risk	98.20%	95.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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