XML 83 R51.htm IDEA: XBRL DOCUMENT
v3.25.1

Redeemable Convertible Preferred Stock (Details) $ / shares in Units, $ in Thousands | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
May 31, 2024 USD ($) $ / shares shares | Mar. 31, 2024 USD ($) instrument $ / shares shares | Oct. 31, 2023 USD ($) $ / shares shares | May 31, 2023 USD ($) $ / shares shares | Dec. 31, 2023 USD ($) | Jul. 31, 2023 shares
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Offering cost |  |  |  |  | $ 485 |
Derivative liability |  |  |  | $ 2,100 |  |
Derivative liability reclassified to temporary equity |  |  | $ 2,200 |  |  |
Number of Freestanding Financial Instruments | instrument |  | 2 |  |  |  |
Fair value of freestanding instrument |  | $ 8,900 |  |  |  |
Series B-2 redeemable convertible preferred stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Shares issued | shares |  |  | 4,221,170 | 10,722,340 |  |
Proceeds from issuance of shares |  |  | $ 21,100 | $ 53,600 |  |
Issue price per share | $ / shares |  |  | $ 5 | $ 5 |  |
Number of convertible preferred shares issued | shares |  |  |  |  |  | 1,277,660
Series B-2 redeemable convertible preferred stock | Maximum |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Offering cost |  |  | $ 100 |  |  |
Series B-2A redeemable convertible preferred stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Shares issued | shares |  |  | 1,778,830 | 1,277,660 |  |
Proceeds from issuance of shares |  |  | $ 8,900 | $ 6,400 |  |
Issue price per share | $ / shares |  |  | $ 5.00 | $ 5.00 |  |
Series C redeemable convertible preferred stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Shares issued | shares | 41,264,892 | 41,264,891 |  |  |  |
Proceeds from issuance of shares | $ 129,500 | $ 129,500 |  |  |  |
Offering cost | $ 200 | $ 400 |  |  |  |
Issue price per share | $ / shares | $ 3.13826 | $ 3.13826 |  |  |  |
Derivative liability reclassified to temporary equity | $ 14,300 |  |  |  |  |
Number of Freestanding Financial Instruments | instrument |  | 2 |  |  |  |
Series C-1 redeemable convertible preferred stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Issue price per share | $ / shares |  | $ 4 |  |  |  |
Series B-2, B-2A redeemable convertible preferred stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Offering cost |  |  |  | $ 200 |  |
Voting common stock |  |  |  |  |  |
Redeemable Convertible Preferred Stock |  |  |  |  |  |
Number of shares issued upon conversion | shares |  | 0.1 |  |  |  |

X
- Definition Number of convertible preferred shares issued for each share of convertible preferred stock that is converted. + References No definition available. + Details
Name: | alms_ConvertiblePreferredStockNumberOfSharesIssuedUponConversion
Namespace Prefix: | alms_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of derivative liability reclassified into temporary equity. + References No definition available. + Details
Name: | alms_DerivativeLiabilityAmountReclassifiedToTemporaryEquity
Namespace Prefix: | alms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Market value / fair value of freestanding financial instruments held by the company. + References No definition available. + Details
Name: | alms_FairValueOfFreestandingFinancialInstruments
Namespace Prefix: | alms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of freestanding financial instruments held by the company. + References No definition available. + Details
Name: | alms_NumberOfFreestandingFinancialInstruments
Namespace Prefix: | alms_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Redeemable convertible preferred stock recognized call option + References No definition available. + Details
Name: | alms_RedeemableConvertiblePreferredStockCallOption
Namespace Prefix: | alms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of shares issued as redeemable preferred stock during the period. + References No definition available. + Details
Name: | alms_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | alms_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued for each share of convertible preferred stock that is converted. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(27)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-16 + Details
Name: | us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-15 + Details
Name: | us-gaap_PaymentsOfStockIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow from issuance of callable preferred stock which is identified as being convertible to another type of financial security at the option of the issuer or the holder. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 14 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-14 + Details
Name: | us-gaap_ProceedsFromIssuanceOfRedeemableConvertiblePreferredStock
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: | dtr-types: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_TemporaryEquityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_SeriesB2RedeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_SeriesB2aRedeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_SeriesCRedeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_SeriesC1RedeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_SeriesB2B2aRedeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=alms_VotingCommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |