XML 43 R33.htm IDEA: XBRL DOCUMENT
v3.19.3

Stock Warrants - Warrant liability (Details) - $ / shares |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | ---
Oct. 10, 2014 | Nov. 18, 2016 | Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Closing stock price | $ 61.25 |  | $ 0.56
Expected dividends | 0.00% |  | 0.00%
Expected volatility | 95.00% |  | 110.00%
Risk free interest rate | 1.39% |  | 2.60%
Expected life of warrant | 5 years |  | 9 months 15 days
Series A Warrants [Member] |  |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |  |
Closing stock price |  | $ 31.15 | $ 0.56
Expected dividends |  | 0.00% | 0.00%
Expected volatility |  | 85.00% | 92.50%
Risk free interest rate |  | 1.58% | 2.50%
Expected life of warrant |  | 4 years | 1 year 10 months 24 days

X
- Definition Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price). + References No definition available. + Details
Name: | syn_FairValuesAssumptionsExpectedDividendRate
Namespace Prefix: | syn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | syn_FairValuesAssumptionsExpectedTerms
Namespace Prefix: | syn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price. + References No definition available. + Details
Name: | syn_FairValuesAssumptionsExpectedVolatilityRate
Namespace Prefix: | syn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Risk-free interest rate assumption used in valuing an instrument. + References No definition available. + Details
Name: | syn_FairValuesAssumptionsRiskFreeInterestRate
Namespace Prefix: | syn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
Name: | us-gaap_SharePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=syn_StockWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |