Related Party Transactions (Details) $ / shares in Units, ¥ in Millions, shares in Millions		1 Months Ended								3 Months Ended					12 Months Ended
	Jun. 05, 2020 USD ($) $ / shares shares	Oct. 31, 2021 USD ($) day	Sep. 30, 2020 USD ($)	Sep. 30, 2020 CNY (¥)	May 31, 2020 USD ($)	Nov. 30, 2019 USD ($) installment	Jul. 31, 2019 USD ($)	Jun. 30, 2019 USD ($) shares	Mar. 31, 2019 USD ($) shares	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($) item	Dec. 31, 2018 USD ($)	Dec. 31, 2021 USD ($) Y	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	May 31, 2020 CNY (¥)	Nov. 25, 2019 USD ($) $ / shares	Oct. 30, 2019	Feb. 08, 2019 USD ($) $ / shares	May 10, 2012 USD ($) $ / shares
Related Party Transaction [Line Items]
Amount due to related parties															$ 1,102,000		$ 882,000
Expense due to conversion of notes															0		2,266,000	$ 0
Principal															57,811,000		565,000
Long term investment															35,588,000		8,487,000
Impairment loss of intangible assets															71,070,000		33,230,000	73,669,000
Common stock issuance																	182,498,000
Professional fees															34,710,000		12,541,000	5,828,000
Proceeds from issuance of convertible notes															295,000,000		27,000,000	9,132,000
Notes receivable, current															697,000		0
Notes receivable															54,907,000		0
Proceeds from loan repayment															473,000		1,529,000	0
Seven Stars Founder Space Industrial Pte. Ltd ("Founder Space")
Related Party Transaction [Line Items]
Ownership percentage, equity method					50.00%															50.00%
Energica
Related Party Transaction [Line Items]
Ownership percentage, equity method		20.00%
Digital asset management services
Related Party Transaction [Line Items]
Assets sold under agreements carrying amount															$ 7,100,000
Fuzhou Note Receivable
Related Party Transaction [Line Items]
Notes receivable provided					$ 400,000															¥ 3.0
Notes receivable					$ 500,000															3.3
Repayment period					3 months
Recorded reserve against notes receivable					$ 500,000
Zhu Note Receivable
Related Party Transaction [Line Items]
Notes receivable provided					1,400,000															10.0
Notes receivable					$ 1,500,000															¥ 10.5
Repayment period					1 month
Proceeds from loan repayment			$ 1,500,000	¥ 10.5
GTB Tokens
Related Party Transaction [Line Items]
Impairment loss of intangible assets												$ 61,100,000						61,100,000
Borrowing from Dr. Wu. and his affiliates
Related Party Transaction [Line Items]
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59
Amount of debt converted	$ 1,500,000
Amount of debt transferred	$ 400,000
Expected discount rate | Digital asset management services
Related Party Transaction [Line Items]
Measurement input															0.760
Expected term (years) | Digital asset management services
Related Party Transaction [Line Items]
Measurement input | Y															3.0
Expected volatility | Digital asset management services
Related Party Transaction [Line Items]
Measurement input															1.55
Expected dividend yield | Digital asset management services
Related Party Transaction [Line Items]
Measurement input															0
Risk-free interest rate | Digital asset management services
Related Party Transaction [Line Items]
Measurement input															2.25
Level 2 | Digital asset management services
Related Party Transaction [Line Items]
Proceeds from sale of assets (in shares)															$ 40,700,000			40,700,000
Borrowing from Dr. Wu. and his affiliates
Related Party Transaction [Line Items]
Amount due to related parties															200,000		200,000
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59
Shares issued upon conversion of debt (in shares) | shares	2.6
Amount of debt transferred											$ 400,000
Accounts payables															700,000		600,000
Delaware Board Of Trade Holdings Inc
Related Party Transaction [Line Items]
Interest rate of convertible note								0.00%
Short-term debt								$ 600,000
Repayments of short term debt							$ 300,000
Seven Stars Founder Space Industrial Pte. Ltd ("Founder Space") | Zhu Note Receivable
Related Party Transaction [Line Items]
Ownership interest provided as collateral (as a percent)					50.00%															50.00%
Mobile Energy Group
Related Party Transaction [Line Items]
Percentage of ownership interest								50.10%
Shenma
Related Party Transaction [Line Items]
Common stock issuance						$ 4,900,000
Number of installments | installment						6
Payments to acquire equity Interest															500,000		500,000
Shenma | Qianxi
Related Party Transaction [Line Items]
Percentage of ownership interest																						1.72%
Grapevine Logic, Inc. ("Grapevine") | Paycheck Protection Program | Unsecured Debt
Related Party Transaction [Line Items]
Proceeds from issuance of convertible notes															100,000
Qianxi
Related Party Transaction [Line Items]
Number of Ev taxis order to third party | item													4,172
Commission payable on completion of order													$ 2,700,000
iUnicorn | Mobile Energy Group
Related Party Transaction [Line Items]
Percentage of ownership interest								49.90%
Vice Chairman | Related party personal expenses
Related Party Transaction [Line Items]
Personal expenses															100,000
Service agreement with SSSIG
Related Party Transaction [Line Items]
Due to other related parties															600,000
Transaction with related party										$ 400,000
Professional fees															400,000		700,000
Service agreement with SSSIG | Selling, general and administrative expenses
Related Party Transaction [Line Items]
Transaction with related party																$ 1,400,000
Glory
Related Party Transaction [Line Items]
Amount due to related parties															500,000
Net balance due to related parties															200,000		300,000
Affiliated Entity
Related Party Transaction [Line Items]
Notes receivable, current															700,000
Interest income recognized															6,476
Affiliated Entity | Revolving Credit Facility
Related Party Transaction [Line Items]
Notes receivable		$ 4,500,000
Loan receivable due date | day		210
Affiliated Entity | Revolving Credit Facility | Prime Rate
Related Party Transaction [Line Items]
Interest rate		4.00%
Affiliated Entity | Ocasia Group Holding LTD
Related Party Transaction [Line Items]
Personal expenses															200,000
Affiliated Entity | Acquisition Of Fintalk Assets
Related Party Transaction [Line Items]
Cash amount														$ 1,000,000					$ 1,000,000
Common stock, fair market value														5,400,000					6,000,000
Shares issued (in shares) | shares								2.9
Impairment loss												$ 5,700,000
Transaction with related party														$ 6,400,000					7,000,000
Personal expenses																			$ 1,000,000
Research and development contract with a related party | Research and development expense
Related Party Transaction [Line Items]
Transaction with related party															2,800,000
Service charges																	1,600,000
GTD
Related Party Transaction [Line Items]
Assets sold under agreements carrying amount									$ 20,400,000
Sales from sale of productive assets (in shares) | shares									1.3
GTD | License content
Related Party Transaction [Line Items]
Licensed content															17,000,000
GTD | Animation copy right
Related Party Transaction [Line Items]
Assets sold under agreements carrying amount															200,000
GTD | Nanjing Shengyi Network Technology Co., Ltd
Related Party Transaction [Line Items]
Long term investment															$ 3,200,000
GTD | Nanjing Shengyi Network Technology Co., Ltd | Ideanomics, Inc
Related Party Transaction [Line Items]
Percentage of ownership interest															13.00%
Convertible Note | Vice Chairman
Related Party Transaction [Line Items]
Amount due to related parties																								$ 3,000,000
Interest rate of convertible note																								4.00%
Conversion price of convertible note after amendment (in dollars per share) | $ / shares																								$ 1.75
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59																							$ 1.50
Shares issued upon conversion of debt (in shares) | shares	5.1
Expense due to conversion of notes																	1,500,000
Interest expense																	300,000
$2.5 Million Convertible Promissory Note | SSSIG
Related Party Transaction [Line Items]
Advance received without any interest																							$ 1,300,000
Convertible promissory note amount not received																							$ 1,200,000
$2.5 Million Convertible Promissory Note | Mr Bruno Wu
Related Party Transaction [Line Items]
Expense due to conversion of notes																	700,000
Interest expense															$ 0		100,000	100,000
$2.5 Million Convertible Promissory Note | Mr Bruno Wu | SSSIG
Related Party Transaction [Line Items]
Interest rate of convertible note																							4.00%
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59																						$ 1.83
Shares issued upon conversion of debt (in shares) | shares	2.2
Interest expense															0		21,546	48,357
Principal																							$ 2,500,000
Convertible Promissory Note | Mr Bruno Wu | SSSIG
Related Party Transaction [Line Items]
Interest rate of convertible note																					4.00%
Conversion price of note convertible (in dollars per share) | $ / shares																					$ 1.25
Principal																					$ 1,000,000
$1.0 Million Convertible Promissory Note | SSSIG
Related Party Transaction [Line Items]
Advance received without any interest																					300,000
Convertible promissory note amount not received																					$ 800,000
$1.0 Million Convertible Promissory Note | Mr Bruno Wu
Related Party Transaction [Line Items]
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59
Shares issued upon conversion of debt (in shares) | shares	0.4
Expense due to conversion of notes																	100,000
$1.0 Million Convertible Promissory Note | Mr Bruno Wu | SSSIG
Related Party Transaction [Line Items]
Interest expense															$ 0		$ 4,301	$ 1,000