| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q |
| ASSETS | | | | | | | | |
| Current assets: | | | | | | | | |
| Cash | 58.7 | 16.8 | 20.1 | 26.9 | 39.2 | 42.6 | 35.4 | 32.3 |
| Accounts receivable, net | 33.0 | 32.1 | 35.1 | 27.8 | 27.8 | 28.6 | 24.2 | 18.3 |
| Inventory, net | 14.3 | 14.2 | 13.5 | 14.6 | 13.5 | 10.8 | 9.2 | 10.0 |
| Prepaid expenses and other | 1.5 | 2.1 | 0.9 | 1.4 | 1.6 | 0.7 | 1.1 | 1.2 |
| Total current assets | 107.6 | 65.2 | 69.6 | 70.6 | 82.2 | 82.7 | 69.9 | 61.8 |
| Property and equipment, net | 2.4 | 2.3 | 2.2 | 2.3 | 2.2 | 2.2 | 2.3 | 2.4 |
| Operating lease asset | 10.9 | 11.9 | 12.8 | 14.7 | 15.6 | 16.3 | 17.2 | 18.1 |
| Finance lease asset | 0.2 | 0.2 | 0.3 | 0.3 | 0.4 | 0.4 | 0.4 | 0.4 |
| Deposits | 0.7 | 0.7 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 |
| Intangible assets, net of accumulated amortization | 8.6 | 8.8 | 9.1 | 9.5 | 9.8 | 10.0 | | |
| Goodwill | 20.4 | 20.4 | 20.4 | 20.4 | 20.4 | 20.4 | | |
| Deferred income taxes | 1.8 | 1.6 | 1.6 | 1.1 | 0.9 | 0.7 | 0.4 | 0.4 |
| Total assets | 152.6 | 111.1 | 116.5 | 119.6 | 132.0 | 133.3 | 90.7 | 83.7 |
| |
| LIABILITIES AND STOCKHOLDERS' EQUITY | | | | | | | | |
| Current liabilities: | | | | | | | | |
| Accounts payable and accrued expenses | 12.0 | 11.6 | 5.6 | 5.2 | 6.5 | 4.7 | 6.2 | 6.0 |
| Cash dividends payable | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 3.6 | | |
| Operating lease liability | 1.9 | 2.0 | 2.5 | 3.4 | 3.3 | 2.9 | 2.4 | 2.4 |
| Finance lease liability | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 |
| Income taxes payable | | 2.0 | 2.0 | 0.2 | 3.1 | 2.3 | 1.6 | 0.4 |
| Current portion of debt | | 5.3 | 5.3 | 5.3 | 5.3 | 5.3 | | |
| Accrued payroll and related taxes | 6.1 | 5.9 | 5.5 | 4.6 | 3.9 | 3.9 | 3.5 | 3.4 |
| Total current liabilities | 14.1 | 21.1 | 21.1 | 18.8 | 22.4 | 22.9 | 10.3 | 8.9 |
| |
| Long-term liabilities: | | | | | | | | |
| Convertible senior notes, less issuance costs | 57.2 | | | | | | | |
| Contingent consideration | 6.9 | 8.6 | 10.0 | 9.6 | 9.5 | 9.7 | | |
| Operating lease liability | 12.0 | 12.8 | 13.5 | 13.9 | 14.8 | 15.9 | 16.7 | 17.1 |
| Finance lease liability | 0.1 | 0.2 | 0.2 | 0.3 | 0.3 | 0.3 | 0.3 | 0.4 |
| Total liabilities | 90.3 | 46.6 | 50.1 | 50.6 | 56.2 | 59.3 | 27.3 | 26.4 |
| |
| Commitments and contingencies | | | | | | | | |
| Stockholders' equity: | | | | | | | | |
| Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued and outstanding as of June 30, 2023 and December 31, 2022 | | | | | | | | |
| Common stock | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Additional paid-in capital | 82.9 | 82.3 | 82.4 | 81.4 | 80.9 | 80.4 | 38.2 | 37.7 |
| Treasury stock of 5,151,913 and 4,253,015 shares at June 30, 2023 and December 31, 2022, respectively, at cost | -42.6 | | | | | | | |
| Retained earnings | 22.0 | 18.6 | 17.0 | 4.7 | 1.4 | | 31.6 | 25.5 |
| Total stockholders' equity | 62.3 | 64.5 | 66.4 | 69.0 | 75.8 | 73.9 | 63.4 | 57.3 |
| Total liabilities and stockholders' equity | 152.6 | 111.1 | 116.5 | 119.6 | 132.0 | 133.3 | 90.7 | 83.7 |