Related Party Transactions (Details) $ / shares in Units, ¥ in Millions, shares in Millions				1 Months Ended				3 Months Ended						6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 05, 2020 USD ($) $ / shares shares	May 01, 2020 USD ($)	Apr. 10, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 CNY (¥)	May 31, 2020 USD ($)	Nov. 30, 2019 USD ($) installment	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($) $ / shares	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	May 31, 2020 CNY (¥)	Nov. 25, 2019 USD ($) $ / shares	Feb. 08, 2019 USD ($) $ / shares	May 10, 2012 USD ($) $ / shares
Related Party Transaction [Line Items]
Amount due to related parties								$ 1,112,000						$ 1,112,000	$ 1,112,000			$ 882,000
Principal amount								417,000						417,000	417,000			565,000
Interest expense											$ 2,000,000					$ 14,200,000
Salary, severance and expenses																100,000
Due to other related parties								100,000						100,000	100,000			100,000
Accrued expenses, salary and other current liabilities															6,971,000	(3,827,000)
Professional fees								9,387,000			3,968,000				21,994,000	8,096,000
Common stock issuance										$ 53,407,000		$ 32,502,000	$ 1,000,000
Payments to acquire equity Interest															100,579,000	0
Unpaid consideration															220,000,000	2,000,000
Paycheck Protection Program | Unsecured Debt
Related Party Transaction [Line Items]
Interest rate			1.00%
Interest expense								851							2,899
Unpaid consideration			$ 300,000
Vice Chairman | Related Party Personal Expenses
Related Party Transaction [Line Items]
Expenses from transactions with related party								100,000
Service agreement with SSSIG
Related Party Transaction [Line Items]
Due to other related parties								600,000						600,000	600,000
Related party transaction, amounts of transaction									$ 400,000								$ 1,400,000
Professional fees								400,000							400,000
Glory
Related Party Transaction [Line Items]
Due to other related parties																		500,000
Payments for related party																		200,000
Amounts due from related party								200,000						200,000	200,000			300,000
Affiliated Entity
Related Party Transaction [Line Items]
Note receivable						$ 1,400,000													¥ 10.0
Note receivable due one month from disbursement						$ 1,500,000													¥ 10.5
Repayment period						1 month
Repayment of note receivable				$ 1,500,000	¥ 10.5
Affiliated Entity | Ocasia Group Holding LTD
Related Party Transaction [Line Items]
Expenses from transactions with related party								200,000
Returned amount								200,000
Affiliated Entity | Research And Development Contract
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction											2,800,000
Expenses from transactions with related party											1,300,000
Borrowing from Dr. Wu. and his affiliates
Related Party Transaction [Line Items]
Amount due to related parties								200,000						200,000	200,000			200,000
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59											$ 0.59
Shares issued upon conversion of debt (in shares) | shares	2.6
Debt conversion, amount	$ 1,500,000
Debt instrument, increase (decrease), net	$ 400,000											$ 400,000
Payables from related party								$ 700,000						700,000	700,000			$ 600,000
SSSIG | Borrowing from Dr. Wu. and his affiliates
Related Party Transaction [Line Items]
Shares issued upon conversion of debt (in shares) | shares	0.4
Accrued expenses, salary and other current liabilities														$ 400,000
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]
Interest rate		1.00%
Unpaid consideration		$ 100,000
Prime Capital Enterprise Pte. Ltd. | Seven Stars Founder Space Industrial Pte. Ltd
Related Party Transaction [Line Items]
Percentage of ownership interest						50.00%													50.00%
Seven Stars Innovative Industries Group Limited | Seven Stars Founder Space Industrial Pte. Ltd
Related Party Transaction [Line Items]
Percentage of ownership interest						50.00%													50.00%
Convertible Note | Vice Chairman
Related Party Transaction [Line Items]
Amount due to related parties																						$ 3,000,000
Principal amount																						$ 3,000,000
Interest rate																						4.00%
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59																					$ 1.75
Conversion price of convertible note after amendment (in dollars per share) | $ / shares																						$ 1.50
Interest expense											0					50,959
Shares issued upon conversion of debt (in shares) | shares	5.1
Interest payable	$ 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 | SSSIG | Bruno Wu ("Mr.Wu")
Related Party Transaction [Line Items]
Principal amount																					$ 2,500,000
Interest rate																					4.00%
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59																				$ 1.83
Interest expense											0					21,546
Shares issued upon conversion of debt (in shares) | shares	2.2
$1.0 Million Convertible Promissory Note | SSSIG
Related Party Transaction [Line Items]
Advance received without any interest																				$ 250,000
Convertible promissory note amount not received																				800,000
$1.0 Million Convertible Promissory Note | SSSIG | Bruno Wu ("Mr.Wu")
Related Party Transaction [Line Items]
Principal amount																				$ 1,000,000
Interest rate																				4.00%
Conversion price of note convertible (in dollars per share) | $ / shares	$ 0.59																			$ 1.25
Interest expense											$ 0					$ 4,301