XML 60 R49.htm IDEA: XBRL DOCUMENT
v3.19.1

Common Stock - Additional Information (Detail) $ / shares in Units, $ in Millions |  |  |  | 6 Months Ended |
--- | --- | --- | --- | --- | ---
Sep. 11, 2018 $ / shares shares | Aug. 14, 2018 USD ($) $ / shares shares | Aug. 08, 2018 shares | Mar. 31, 2019 USD ($) $ / shares shares | Sep. 30, 2018 $ / shares shares
Class of Warrant or Right [Line Items] |  |  |  |  |
Warrants term |  |  |  | 5 years |
Warrants of common stock exercise price | $ / shares |  |  |  | $ 0.004 |
Maximum percentage of stock pertaining to restrictions |  |  |  | 24.90% |
Extended term of outstanding warrants expiration period |  |  |  | 5 years |
Warrants of common stock expiration date |  |  |  | Sep. 30, 2023 |
Warrants to purchase shares of common stock |  |  |  | 250,000 |
Common stock, stock split |  |  |  | Effected a 2.5-for-1 stock split |
Stock split ratio |  |  | 2.5 |  |
Common stock, shares authorized |  |  | 125,000,000 | 125,000,000 | 125,000,000
Preferred stock, shares authorized |  |  | 5,000,000 | 5,000,000 | 5,000,000
Stock issued during period, shares, new issues | 1,344,500 |  |  |  |
Common stock, no par value | $ / shares |  |  |  | $ 0 | $ 0
Common stock, warrants issued |  |  |  | 6,780,297 | 10,614,990
IPO [Member] |  |  |  |  |
Class of Warrant or Right [Line Items] |  |  |  |  |
Stock issued during period, shares, new issues |  | 9,630,000 |  |  |
Common stock, no par value | $ / shares |  |  |  |  |
Shares issued, price per share | $ / shares |  | $ 12.00 |  |  |
Gross proceeds of initial public offering | $ |  | $ 115.6 |  | $ 124.2 |
Net proceeds from initial public offering | $ |  |  |  | 111.7 |
Underwriting discounts and commissions | $ |  |  |  | 8.7 |
Offering costs | $ |  |  |  | $ 3.8 |
Underwriter Options [Member] |  |  |  |  |
Class of Warrant or Right [Line Items] |  |  |  |  |
Common stock, warrants issued |  | 1,444,500 |  |  |
Purchased Directly From Company [Member] |  |  |  |  |
Class of Warrant or Right [Line Items] |  |  |  |  |
Stock issued during period, shares, new issues | 723,985 |  |  |  |
Purchased Directly From Selling Shareholders [Member] |  |  |  |  |
Class of Warrant or Right [Line Items] |  |  |  |  |
Stock issued during period, shares, new issues | 620,515 |  |  |  |
Firm Shares and Option Shares [Member] |  |  |  |  |
Class of Warrant or Right [Line Items] |  |  |  |  |
Shares issued, price per share | $ / shares | $ 12.00 |  |  |  |

X
- Definition Class of warrants or right issued. + References No definition available. + Details
Name: | mesa_ClassOfWarrantsOrRightIssued
Namespace Prefix: | mesa_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Extended term of outstanding warrants expiration period. + References No definition available. + Details
Name: | mesa_ExtendedTermOfOutstandingWarrantsExpirationPeriod
Namespace Prefix: | mesa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of stock pertaining to restrictions. + References No definition available. + Details
Name: | mesa_MaximumPercentageOfStockPertainingToRestrictions
Namespace Prefix: | mesa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Offering costs. + References No definition available. + Details
Name: | mesa_OfferingCosts
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Proceeds from issuance initial public offering net of issuance costs. + References No definition available. + Details
Name: | mesa_ProceedsFromIssuanceInitialPublicOfferingNetOfIssuanceCosts
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Underwriting discounts and commissions. + References No definition available. + Details
Name: | mesa_UnderwritingDiscountsAndCommissions
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Date the warrants or rights are exercisable, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(3)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face amount per share of no-par value common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockNoParValue
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash inflow associated with the amount received from entity's first offering of stock to the public. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceInitialPublicOffering
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Per share or per unit amount of equity securities issued. + References No definition available. + Details
Name: | us-gaap_SharesIssuedPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the stock split arrangement. Also provide the retroactive effect given by a stock split that occurs after the balance date but before the release of financial statements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 4.C) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770 + Details
Name: | us-gaap_StockholdersEquityNoteStockSplit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB TOPIC 4.C) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770 + Details
Name: | us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
Name: | us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=mesa_UnderwriterOptionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=mesa_PurchasedDirectlyFromEntityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=mesa_PurchasedDirectlyFromSellingShareholdersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=mesa_FirmSharesAndOptionSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |