XML 40 R35.htm IDEA: XBRL DOCUMENT
v3.19.3

Financial Instruments (Narrative) (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Financial Instruments [Line Items] |  |  |  |
Realized loss or gains | $ 0 | $ 0 | $ 0 | $ 0
US Treasury and Government Short-term Debt Securities [Member] |  |  |  |
Financial Instruments [Line Items] |  |  |  |
Available for Sale Securities Maturity Period |  |  | 5 years |

X
- Definition Number of maturity year relating to investment securities. + References No definition available. + Details
Name: | med_AvailableForSaleSecuritiesMaturityPeriod
Namespace Prefix: | med_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | med_FinancialInstrumentsLineItems
Namespace Prefix: | med_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in debt and equity securities. + References No definition available. + Details
Name: | us-gaap_DebtAndEquitySecuritiesRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USTreasuryAndGovernmentShorttermDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |