XML 43 R31.htm IDEA: XBRL DOCUMENT
v3.25.3

Balance Sheet Components (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Balance Sheet Components |
Schedule of other prepaid expenses and current assets | Other prepaid expenses and current assets consisted of the following as of September 30, 2025 and December 31, 2024 (in thousands):
​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | September 30, |  | December 31,
​ | ​ | 2025 | ​ | 2024
Prepaid credit voucher for clinical manufacturing | ​ | $ | 3,222 | ​ | $ | —
Interest receivable | ​ | ​ | 1,987 | ​ | ​ | 698
Prepaid subscriptions | ​ | ​ | 1,657 | ​ | ​ | 1,232
Tax receivable | ​ | ​ | 1,650 | ​ | ​ | 1,114
Prepaid insurance | ​ | ​ | 1,094 | ​ | ​ | 695
Other | ​ |  | 1,001 | ​ |  | 762
Total other prepaid expenses and current assets | ​ | $ | 10,611 | ​ | $ | 4,501
Schedule of property and equipment, net | Property and equipment, net consisted of the following as of September 30, 2025 and December 31, 2024 (in thousands):
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | Estimated Useful Life |  | September 30, |  | December 31,
​ | ​ | (in years) | ​ | 2025 | ​ | 2024
Leasehold improvements |  | Shorter of useful life or lease term | ​ | $ | 17,655 | ​ | $ | 17,618
Laboratory equipment |  | 5 | ​ | ​ | 5,844 | ​ | ​ | 5,227
Furniture and fixtures |  | 5 | ​ |  | 1,709 | ​ |  | 1,709
Computer equipment |  | 5 | ​ |  | 896 | ​ |  | 896
Capitalized software |  | 3 | ​ |  | 75 | ​ |  | 75
Total property and equipment, gross | ​ | ​ | ​ |  | 26,179 | ​ |  | 25,525
Less: Accumulated depreciation and amortization | ​ | ​ | ​ |  | (7,121) | ​ |  | (4,557)
Total property and equipment, net | ​ | ​ | ​ | $ | 19,058 | ​ | $ | 20,968
​
Schedule of other accrued expenses and current liabilities | Other accrued expenses and current liabilities consisted of the following as of September 30, 2025 and December 31, 2024 (in thousands): ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | September 30, |  | December 31,
​ | ​ | 2025 | ​ | 2024
Accrued personnel and related expenses | ​ | $ | 12,167 | ​ | $ | 7,765
Accrued professional services and other | ​ |  | 5,217 | ​ |  | 2,657
Severance liability | ​ | ​ | 1,374 | ​ | ​ | —
Accrued other expenses | ​ |  | 63 | ​ |  | 158
Total other accrued expenses and current liabilities | ​ | $ | 18,821 | ​ | $ | 10,580
​

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

X
- Definition Tabular disclosure of expenses incurred but not yet paid nor invoiced, classified as other and liabilities classified as other. + References No definition available. + Details
Name: | alms_ScheduleOfOtherAccruedExpensesAndCurrentLiabilitiesTableTextBlock
Namespace Prefix: | alms_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of asset related to consideration paid in advance for costs that provide economic benefits in future periods, classified as other and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer. + References No definition available. + Details
Name: | alms_ScheduleOfOtherPrepaidExpensesAndCurrentAssetsTableTextBlock
Namespace Prefix: | alms_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -SubTopic 10 -Topic 360 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-1 + Details
Name: | us-gaap_PropertyPlantAndEquipmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration