XML 41 R33.htm IDEA: XBRL DOCUMENT
v3.22.1

Common Stock - Issued and Outstanding Shares - Additional Information (Detail) - USD ($) |  | 3 Months Ended
--- | --- | ---
May 27, 2021 | Mar. 31, 2022 | Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Stock option exercises, Shares |  | 0 | 0
Restricted stock unit settlements |  | 0 | 0
May 2021 Public Offering [Member] |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Gross proceeds from issuance of common stock | $ 23,000,000.0 |  |
Underwriting discounts and commissions and offering expenses | 1,700,000 |  |
Proceeds from issuance of common stock | $ 21,300,000 |  |
At-the-Market Sales Agreement [Member] |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Common stock, shares issued |  | 12,742 |
Common stock aggregate maximum offering amount |  | $ 25,000,000 |
Gross proceeds |  | 100,000 |
Common stock available for sale under offering |  | $ 24,900,000 |
Common stock [Member] |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Common stock, shares issued |  | 3,584 | 2,965
Common stock [Member] | May 2021 Public Offering [Member] |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Common stock, shares issued | 3,285,714 |  |
Common stock, price per share | $ 7.00 |  |
Common stock [Member] | Underwriters Over-Allotment Option Exercise [Member] |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |
Common stock, shares issued | 428,571 |  |

X
- Definition Common stock aggregate maximum offering amount. + References No definition available. + Details
Name: | achv_CommonStockAggregateMaximumOfferingAmount
Namespace Prefix: | achv_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Common stock, shares available for future grant. + References No definition available. + Details
Name: | achv_CommonStockSharesAvailableForFutureGrant
Namespace Prefix: | achv_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Gross proceeds from issuance of common stock. + References No definition available. + Details
Name: | achv_GrossProceedsFromIssuanceOfCommonStock
Namespace Prefix: | achv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Proceeds from issuance of common stock gross. + References No definition available. + Details
Name: | achv_ProceedsFromIssuanceOfCommonStockGross
Namespace Prefix: | achv_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition The cash inflow from the additional capital contribution to the entity. + 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=123570139&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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: | dtr-types: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=120391452&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=123467817&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=120397183&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=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited. + References Reference 1: 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=123467817&loc=d3e21463-112644 Reference 2: 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=120397183&loc=d3e187085-122770 Reference 3: 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=120391452&loc=d3e13212-122682 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(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of share options (or share units) exercised during the current period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 Reference 2: 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=120397183&loc=d3e187085-122770 Reference 3: 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=120391452&loc=d3e13212-122682 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(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 5: 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=123467817&loc=d3e21463-112644 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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

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

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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