| In millions, except per share items | Dec-31-12 | Dec-31-11 | Dec-31-10 | Dec-31-09 | Dec-31-08 |
| | 10-K | 10-K | 10-K | 10-K | S-1/A |
| Revenue | 278.9 | 241.6 | 186.1 | 131.2 | 106.0 |
| Revenue growth | 15.4% | 29.8% | 41.9% | 23.8% | |
| Cost and expenses | | | | | |
| Fleet operations | 173.6 | 159.2 | 122.6 | 93.4 | |
| Member services and fulfillment | 20.0 | 19.5 | 15.1 | 10.4 | |
| Research and development | 4.5 | 3.9 | 3.2 | 2.3 | |
| Selling, general and administrative | 71.6 | 57.1 | 49.2 | 30.0 | |
| |
| Amortization of acquired intangible assets | | | | | |
| Total operating expenses | 272.8 | 243.6 | 193.5 | 137.1 | |
| Income (loss) from operations | 6.1 | -2.0 | -7.4 | -5.9 | |
| Operating margin | 2.2% | -0.8% | -4.0% | -4.5% | |
| |
| Other income (expense) | | | | | |
| Interest income | 0.4 | 0.1 | 0.0 | 0.1 | |
| Interest expense | -4.4 | -8.6 | -8.2 | -2.5 | |
| Other, net | 1.2 | 3.0 | 1.7 | -3.7 | |
| Income (loss) before income taxes | 3.3 | -7.4 | -13.8 | -4.6 | -14.5 |
| Provision (benefit) for income taxes | -10.9 | -0.3 | 0.3 | 0.1 | |
| Tax rate | | 3.6% | | | 0.0% |
| Net income (loss) | 14.2 | -7.1 | -14.1 | -4.7 | |
| Less: net (income) loss attributable to redeemable noncontrolling interest | 0.5 | 0.0 | 0.0 | 0.0 | |
| Net income (loss) attributable to Zipcar, Inc. | 14.7 | -7.2 | -14.1 | -4.6 | |
| |
| Net income (loss) attributable to common stockholders per share: | | | | | |
| Basic | $0.37 | ($0.24) | ($2.74) | ($2.23) | |
| Diluted | $0.35 | ($0.24) | ($2.74) | ($2.23) | |
| |
| Weighted average number of common shares outstanding used in computing per share amounts: | | | | | |
| Basic | 39.9 | 29.4 | 5.1 | 2.1 | |
| Diluted | 41.5 | 29.4 | 5.1 | 2.1 | |