Summary of Significant Accounting Policies - Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)
Assets and liabilities carried at fair value measured on a recurring basis
Trading Securities	$ 10,636	$ 10,168
Derivative liability	0	0
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) \| Money Market Funds
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	0	0
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) \| Time Deposits
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	0
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)
Assets and liabilities carried at fair value measured on a recurring basis
Trading Securities	256	564
Derivative liability	49,703	9,756
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) \| Money Market Funds
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	62,657	13,653
SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2) \| Time Deposits
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	2,121
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Assets and liabilities carried at fair value measured on a recurring basis
Trading Securities	0	0
Derivative liability	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) \| Money Market Funds
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) \| Time Deposits
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	0
Estimated Fair Value
Assets and liabilities carried at fair value measured on a recurring basis
Trading Securities	10,892	10,732
Derivative liability	49,703	9,756
Estimated Fair Value \| Money Market Funds
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	62,657	$ 13,653
Estimated Fair Value \| Time Deposits
Assets and liabilities carried at fair value measured on a recurring basis
Cash and cash equivalents	$ 2,121

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

No definition available.

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_TradingSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_BankTimeDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: