Recently Adopted and Recently Issued Accounting Guidance	9 Months Ended
Sep. 30, 2011
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	Note 2. Recently Adopted and Recently Issued Accounting Guidance Adopted On January 1, 2011, Altair adopted changes issued by the Financial Accounting Standards Board (FASB) to revenue recognition for multiple-deliverable arrangements. These changes (a) require separation of consideration received in such arrangements by establishing a selling price hierarchy (not the same as fair value) for determining the selling price of a deliverable, which will be based on available information in the following order: vendor-specific objective evidence, third-party evidence, or estimated selling price; (b) eliminate the residual method of allocation and require that the consideration be allocated at the inception of the arrangement to all deliverables using the relative selling price method, which allocates any discount in the arrangement to each deliverable on the basis of each deliverable’s selling price; (c) require that a vendor determine its best estimate of selling price in a manner that is consistent with that used to determine the price to sell the deliverable on a standalone basis; and (d) expand the disclosures related to multiple-deliverable revenue arrangements. The adoption of these changes had no impact on the Consolidated Financial Statements, as Altair does not currently have any such arrangements with its customers. On January 1, 2011, Altair adopted changes issued by the FASB to disclosure requirements for fair value measurements. Specifically, the changes require a reporting entity to disclose, in the reconciliation of fair value measurements using significant unobservable inputs (Level 3), separate information about purchases, sales, issuances, and settlements (that is, on a gross basis rather than as one net number). These changes were applied to the disclosures in Note 3 to the Consolidated Financial Statements. On January 1, 2011, Altair adopted changes issued by the FASB to the testing of goodwill for impairment. These changes require an entity to perform all steps in the test for a reporting unit whose carrying value is zero or negative if it is more likely than not (more than 50%) that a goodwill impairment exists based on qualitative factors. This will result in the elimination of an entity’s ability to assert that such a reporting unit’s goodwill is not impaired and additional testing is not necessary despite the existence of qualitative factors that indicate otherwise. The adoption of these changes had no impact on the Consolidated Financial Statements. On January 1, 2011, Altair adopted changes issued by the FASB to the disclosure of pro forma information for business combinations. These changes clarify that if a public entity presents comparative financial statements, the entity should disclose revenue and earnings of the combined entity as though the business combination that occurred during the current year had occurred as of the beginning of the comparable prior annual reporting period only. Also, the existing supplemental pro forma disclosures were expanded to include a description of the nature and amount of material, nonrecurring pro forma adjustments directly attributable to the business combination included in the reported pro forma revenue and earnings. The adoption of these changes had no impact on the Consolidated Financial Statements. Issued In June 2011, the FASB issued changes to the presentation of comprehensive income. These changes give an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements; the option to present components of other comprehensive income as part of the statement of changes in stockholders’ equity was eliminated. The items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income were not changed. Additionally, no changes were made to the calculation and presentation of earnings per share. These changes become effective for Altair on January 1, 2012. Management is currently evaluating these changes to determine which option will be chosen for the presentation of comprehensive income. Other than the change in presentation, management has determined these changes will not have an impact on the Consolidated Financial Statements. In September 2011, the FASB issued changes to the testing of goodwill for impairment. These changes provide an entity the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not (more than 50%) that the fair value of a reporting unit is less than its carrying amount. Such qualitative factors may include the following: macroeconomic conditions; industry and market considerations; cost factors; overall financial performance; and other relevant entity-specific events. If an entity elects to perform a qualitative assessment and determines that an impairment is more likely than not, the entity is then required to perform the existing two-step quantitative impairment test, otherwise no further analysis is required. An entity also may elect not to perform the qualitative assessment and, instead, go directly to the two-step quantitative impairment test. These changes become effective for Altair for any goodwill impairment test performed on January 1, 2012 or later, although early adoption is permitted. Management has determined these changes will not have an impact on the Consolidated Financial Statements, as Altair has not recognized any goodwill on its Consolidated Financial Statements. Reclassifications - Certain reclassifications have been made to prior period amounts to conform to classifications adopted in the current period.

Recently Adopted and Recently Issued Accounting Guidance

9 Months Ended

Sep. 30, 2011

Description of New Accounting Pronouncements Not yet Adopted [Text Block]

Note 2. Recently Adopted and Recently Issued Accounting Guidance

Adopted

On January 1, 2011, Altair adopted changes issued by the Financial Accounting Standards Board (FASB) to revenue recognition for multiple-deliverable arrangements. These changes (a) require separation of consideration received in such arrangements by establishing a selling price hierarchy (not the same as fair value) for determining the selling price of a deliverable, which will be based on available information in the following order: vendor-specific objective evidence, third-party evidence, or estimated selling price; (b) eliminate the residual method of allocation and require that the consideration be allocated at the inception of the arrangement to all deliverables using the relative selling price method, which allocates any discount in the arrangement to each deliverable on the basis of each deliverable’s selling price; (c) require that a vendor determine its best estimate of selling price in a manner that is consistent with that used to determine the price to sell the deliverable on a standalone basis; and (d) expand the disclosures related to multiple-deliverable revenue arrangements. The adoption of these changes had no impact on the Consolidated Financial Statements, as Altair does not currently have any such arrangements with its customers.

On January 1, 2011, Altair adopted changes issued by the FASB to disclosure requirements for fair value measurements. Specifically, the changes require a reporting entity to disclose, in the reconciliation of fair value measurements using significant unobservable inputs (Level 3), separate information about purchases, sales, issuances, and settlements (that is, on a gross basis rather than as one net number). These changes were applied to the disclosures in Note 3 to the Consolidated Financial Statements.

On January 1, 2011, Altair adopted changes issued by the FASB to the testing of goodwill for impairment. These changes require an entity to perform all steps in the test for a reporting unit whose carrying value is zero or negative if it is more likely than not (more than 50%) that a goodwill impairment exists based on qualitative factors. This will result in the elimination of an entity’s ability to assert that such a reporting unit’s goodwill is not impaired and additional testing is not necessary despite the existence of qualitative factors that indicate otherwise. The adoption of these changes had no impact on the Consolidated Financial Statements.

On January 1, 2011, Altair adopted changes issued by the FASB to the disclosure of pro forma information for business combinations. These changes clarify that if a public entity presents comparative financial statements, the entity should disclose revenue and earnings of the combined entity as though the business combination that occurred during the current year had occurred as of the beginning of the comparable prior annual reporting period only. Also, the existing supplemental pro forma disclosures were expanded to include a description of the nature and amount of material, nonrecurring pro forma adjustments directly attributable to the business combination included in the reported pro forma revenue and earnings. The adoption of these changes had no impact on the Consolidated Financial Statements.

Issued

In June 2011, the FASB issued changes to the presentation of comprehensive income. These changes give an entity the option to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements; the option to present components of other comprehensive income as part of the statement of changes in stockholders’ equity was eliminated. The items that must be reported in other comprehensive income or when an item of other comprehensive income must be reclassified to net income were not changed. Additionally, no changes were made to the calculation and presentation of earnings per share. These changes become effective for Altair on January 1, 2012. Management is currently evaluating these changes to determine which option will be chosen for the presentation of comprehensive income. Other than the change in presentation, management has determined these changes will not have an impact on the Consolidated Financial Statements.

In September 2011, the FASB issued changes to the testing of goodwill for impairment. These changes provide an entity the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not (more than 50%) that the fair value of a reporting unit is less than its carrying amount. Such qualitative factors may include the following: macroeconomic conditions; industry and market considerations; cost factors; overall financial performance; and other relevant entity-specific events. If an entity elects to perform a qualitative assessment and determines that an impairment is more likely than not, the entity is then required to perform the existing two-step quantitative impairment test, otherwise no further analysis is required. An entity also may elect not to perform the qualitative assessment and, instead, go directly to the two-step quantitative impairment test. These changes become effective for Altair for any goodwill impairment test performed on January 1, 2012 or later, although early adoption is permitted. Management has determined these changes will not have an impact on the Consolidated Financial Statements, as Altair has not recognized any goodwill on its Consolidated Financial Statements.

Reclassifications - Certain reclassifications have been made to prior period amounts to conform to classifications adopted in the current period.