| Line Item | Jun 30, 2026 | Mar 31, 2026 | Dec 31, 2025 | Sep 30, 2025 | Jun 30, 2025 | Mar 31, 2025 | Dec 31, 2024 | Sep 30, 2024 | Jun 30, 2024 | Mar 31, 2024 | Dec 31, 2023 | Sep 30, 2023 | Jun 30, 2023 | Mar 31, 2023 | Dec 31, 2022 | Sep 30, 2022 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Net sales | ||||||||||||||||
| YoY growth | +19.6% | +16.6% | +13.6% | +13.4% | ||||||||||||
| Operating expenses: | ||||||||||||||||
| Cost of sales | ||||||||||||||||
| Fulfillment | ||||||||||||||||
| Technology and infrastructure | ||||||||||||||||
| Sales and marketing | ||||||||||||||||
| General and administrative | ||||||||||||||||
| Other operating expense (income), net | ||||||||||||||||
| Total operating expenses | ||||||||||||||||
| % of revenue | 86.3% | 86.9% | 88.3% | 90.3% | ||||||||||||
| Operating income | ||||||||||||||||
| % of revenue | 13.7% | 13.1% | 11.7% | 9.7% | ||||||||||||
| Interest income | ||||||||||||||||
| Interest expense | ||||||||||||||||
| Other income (expense), net | ||||||||||||||||
| Total non-operating income | ||||||||||||||||
| Income before income taxes | ||||||||||||||||
| Provision for income taxes | ||||||||||||||||
| Equity-method investment activity, net of tax | ||||||||||||||||
| Net income | ||||||||||||||||
| % of revenue | 31.2% | 16.7% | 9.9% | 11.8% | ||||||||||||
| Basic earnings per share (in usd per share) | ||||||||||||||||
| Diluted earnings per share (in usd per share) |