| Component: (Network and Table) | |
|---|---|
| Network | 163 - Disclosure - Reconciliation of Provision for Income Taxes at Statutory Rates (Detail) (http://www.achillion.com/taxonomy/role/DisclosureReconciliationOfProvisionForIncomeTaxesAtStatutoryRates) |
| Table | Income Tax Rate Reconciliation [Table] |
| Reporting Entity [Axis] | 0001070336 (http://www.sec.gov/CIK) |
| Legal Entity [Axis] | Entity [Domain] |
| Income Tax Rate Reconciliation [Line Items] | Period [Axis] | ||
|---|---|---|---|
2012-01-01 - 2012-12-31 | 2011-01-01 - 2011-12-31 | 2010-01-01 - 2010-12-31 | |
Federal statutory rate | (.340) | (.340) | (.340) |
State tax, net of federal benefit | (.050) | (.050) | (.050) |
Other | .0005 | .0010 | .0010 |
Share-based compensation | (.0251) | .0130 | .0420 |
Valuation allowance | .4146 | .3760 | .3470 |
Effective Income Tax Rate, Continuing Operations, Total | .00 | .00 | .00 |