| In millions, except per share items | Mar-31-19 | Dec-31-18 | Sep-30-18 | Jun-30-18 | Mar-31-18 | Dec-31-17 | Sep-30-17 | Jun-30-17 |
| | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q |
| Assets | | | | | | | | |
| Current assets: | | | | | | | | |
| Cash and cash equivalents | 19.8 | 40.4 | 35.4 | 27.2 | 20.0 | 29.8 | 28.6 | 30.1 |
| Restricted cash | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 |
| Short-term investments | 48.8 | 52.8 | 54.5 | 53.3 | 49.6 | 44.1 | 41.5 | 32.7 |
| Accounts receivable, net | 30.3 | 33.0 | 34.2 | 29.8 | 26.8 | 29.9 | 30.0 | 26.4 |
| Inventories | 45.9 | 42.7 | 41.6 | 41.7 | 39.3 | 37.2 | 33.1 | 31.0 |
| Prepaid expenses and other current assets | 12.6 | 6.1 | 5.1 | 5.4 | 5.3 | 4.4 | 3.4 | 2.6 |
| Total current assets | 154.7 | 175.2 | 171.0 | 157.8 | 141.3 | 145.6 | 136.9 | 123.0 |
| Property and equipment, net | 9.5 | 9.7 | 8.7 | 7.9 | 7.1 | 7.3 | 7.4 | 6.9 |
| Operating lease right-of-use assets | 10.6 | | | | | | | |
| Long-term investments | 3.2 | | 1.1 | 2.6 | 6.8 | 12.0 | 1.5 | 2.0 |
| Intangible assets, net | 25.4 | 20.7 | 22.0 | 23.3 | 24.6 | 26.1 | 25.7 | 27.0 |
| Goodwill | 31.4 | 21.5 | 21.6 | 21.7 | 21.8 | 21.9 | 21.9 | 21.8 |
| Other assets | 22.6 | 25.5 | 1.3 | 1.5 | 1.5 | 1.6 | 3.1 | 2.7 |
| Total assets | 257.4 | 252.5 | 225.7 | 214.7 | 203.1 | 214.5 | 196.5 | 183.4 |
| |
| Liabilities and stockholders' equity | | | | | | | | |
| Current liabilities: | | | | | | | | |
| Accounts payable | 23.1 | 26.2 | 26.9 | 26.1 | 21.9 | 25.7 | 23.0 | 19.8 |
| Accrued liabilities | 7.2 | 9.1 | 8.4 | 8.3 | 8.2 | 10.8 | 9.4 | 8.3 |
| Current portion of deferred revenue | 5.6 | 5.5 | 5.1 | 5.0 | 4.8 | 4.5 | | |
| Current operating lease liability | 3.9 | | | | | | | |
| Total current liabilities | 39.7 | 40.9 | 40.5 | 39.4 | 34.8 | 41.0 | 34.5 | 30.0 |
| Long-term operating lease liability | 7.9 | | | | | | | |
| Other long-term liabilities | 5.8 | 5.3 | 4.5 | 4.2 | 4.0 | 3.9 | 0.9 | 2.0 |
| Total liabilities | 53.5 | 46.2 | 45.0 | 43.6 | 38.8 | 45.0 | 35.4 | 32.0 |
| |
| Commitments and contingencies (Note 14) | | | | | | | | |
| Stockholders’ equity: | | | | | | | | |
| Common stock | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Additional paid-in capital | 235.0 | 235.5 | 240.4 | 236.4 | 236.2 | 242.3 | 234.6 | 230.1 |
| Accumulated deficit | -30.4 | -28.4 | -58.9 | -64.6 | -71.3 | -72.2 | -73.0 | -78.2 |
| Accumulated other comprehensive loss | -0.8 | -0.8 | -0.8 | -0.7 | -0.6 | -0.5 | -0.5 | -0.5 |
| Total stockholders' equity | 203.8 | 206.3 | 180.7 | 171.1 | 164.3 | 169.5 | 161.1 | 151.4 |
| Total liabilities and stockholders’ equity | 257.4 | 252.5 | 225.7 | 214.7 | 203.1 | 214.5 | 196.5 | 183.4 |